KR0100979

KCGH/MR-021/99

MC-50

-MC-50 AVF Cyclotron Operation -

7)

PLEASE BE AWARE THATALL OF THE MISSING PAGES IN THIS DOCUMENT

WERE ORIGINALLY BLANK

MC-50

1999\1

€ :

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MC-50

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. MC-50

12C(p,p')12C*3i)- 108Ag(p,p')108AgSl V-g-

°11 tfl^r ti}-g-^^, BNCT 7l#7fl^r, 12C(alpha,p)15Nti]:-g-, Investigation of high spin

levels and isomeric states in 140Pr, 142Pm, - fe i ' t

calibration, TLA(thin layer activation)# 6]-§-*}- ^>^

Production of As Isotopes Induced by protons, *&*}# SL-*-} *)£.

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SUMMARY

I . Project Title

MC-50 AVF Cyclotron Operation

n . Objective and Importance of the Project

The MC-50 built first in Korea is a variable energy isochronous cyclotron for the

acceleration (up to 50 MeV) of light particles, which can be used in the fields of

nuclear medicine, physics, biology and engineering. Efficient operation of AVF

MC-50 cyclotron has an important influence on not only the execution of

MOST(Ministry of Science and Technology) project which are mainly on the

researches for the metal material and radionuclide development, the evaluation of

exposure to UsSi, the research for effect on proton irradiation to Zr material but also

radioisotope production and neutron irradiation. The objectives of the project are

chiefly to support the above mentioned, to contribute to promotion of the cyclotron

operation and development for maintenance technology and to build up the

fundamental data of beam extraction from cyclotron. Therefore it is required to

increase the cyclotron reliability and to decrease the failure rate by the preventive

maintenance, efficient operation and prompt solution of general problems.

HI. Scope and Contents of the Project

The efficient operation and secure preventive maintenance have been perform the

- 6 -

neutron irradiation, the radioisotope production and cyclotron application research

without any delay and problems have been promptly solved, so that the cyclotron

could be running constantly. The MC-50 cyclotron has been running for 50.5MeV in

the state of 20 ~ 35 A and for 30, 35 MeV in 20 ~ 50^ A with proton. The data

from the recovery analyses of problems have been piled up in order to be used for

more advanced operation of the cyclotron.

IV. Results and Proposal for Applications

The operation results of the MC-50 cyclotron in 1999 are as follows:

1. Except 63 holidays, actual operation days were 262 of 302 days

which could be operated a year and the rest were 15 days for preventive

maintenance, 13 for repairing glitches and 12 for non-operation due to no-task.

2. Total beam extraction time was 2,473 hours. 18 hours were used for the

neutron irradiation, 1,307 for the radioisotope production and 693 for the application

research.

The average operation rate of 1999 was estimated at 95.3 % which was

similar to last year's 90%. The cyclotron operation has been entered a relatively

stable phase. In addition the operation rate has reached to those of the advanced

countries.

We should take measures as follows to increase the cyclotron availability.

First, it is needed to build the facilities for research on nuclear reaction with beam

irradiation. Beam irradiation to several materials has been performed for radioisotope

production and development in the target room. In the target room for radioisotope

production, however, spacial radiation dose with irradiation due to high beam current

is too high to perform any experiments of other research, so another facilities are

needed.

Secondly, cyclotron should be activated for the industrial use. It is considered

that the cost invested in cyclotron will be satisfied because the industrial application

is the field of high value added research.

Thirdly, it is required to increase the personnels and to exchange information with

advanced countries. MC-50 cyclotron is the only circular accelerator at present in

this country but it is prospected that several similar accelerators will be introduced in

the near future.

- 8 -

41 2 #41 141 2

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73

75

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Fig. 3-1. 4°1#S .M^- &x]5. 33

Fig. 3-2. Percentage comparision of cyclotron operation execution 35

Fig. 3-3. Total Cyclotron Operation Time 36

Fig. 3-4. Monthly Rate of Cyclotron Operation 38

Fig. 3-5. Cyclotron Beam Extraction Time 39

Fig. 3-6. Beam Extraction Time for Radioisotope Production 40

Fig. 3-7. Beam Extraction Time by Radionuclides Kinds 41

Fig. 3-8. Beam Extraction for Cyclotron Application Research 42

Fig. 3-9. Monthly Cyclotron Failure Days 52

Fig. 4-1. m± ^ * H ^ € ^ ^ ^ 1 ^ 5 . 61

Fig. 4-2. # ^ ^ ^ l # ^ Q^S. •• 62

Fig. 4-3. ^-fr°d y<M7l 65

Fig. 4-4. RF tunning #*! 67

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Table 3-4. ^ a^ ^#^°j- # j 48

Table 3-5. ^ S ^ s ] 7-le]#^^ 49

Table 3-6. ^ H « A P S ^ ^ ^ 5 0

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(TRIGA Mark m)# ol-§-§>^ 1-131, Tc-99m^-

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^: Ga-67, In-Ill, 1-123, Tl-201, Br-75,

Rb-81, Mo-99, Pb-203, Cl-34m, Bi-206, At-211, Co-55^

3.0

1 PET(Positron Emission

Tomography)7> 7 ^ ^ ^ 42} PETi 4-§-=l^ # ^ ^ 7 1 , «8= > y^# ^ ^ * 1 C-ll,

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PET PIC-10, PIC-35,

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The Cyclotron Company^ 3.^91 TCC

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Preventive Maintenance Radio-isotope Production

Neutron Therapy Basic Reseach

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3-1

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A ^ " ^ l f H rfl^ ^ ' S ' T S BNCT 7l#7flf, 12C(alpha,p)15N«l-g-,

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3000f

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1000

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I

1998Years

1999

i I I Neutron irradiation • Isotope Production D Research

Fig. 3-3. Total Operation Time Classified Cyclotron Us

$14.

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3-4. Monthly Rate of Cyclotron Operation

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Fig. 3-5. Cyclotron Beam Extraction Time for Neutron Irradiation

200

180

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5. zW*\3] 691,

Vol. 4, No 1, 1990.

6. «}^M, MC-

^ ^ x > «js^ ^ ^ ^ ^ , A^tfl »U]-«i-^ ^ ^ 1989.

7. KfK Progress Report, 42 MeV Cyclotron Facility,

84-F-BURGRJN, 3RD/QRTR/RP October 18, 1984.

8. N. Breteau, R. Sabattier, G. Foin, FIVE YEARS EXPERIENCE

OF NEUTRONTHERAPY WITH THE ORLEANS CYCLOTRON,

Proc. 11th Int. Conf. on Cyclotrons and Applications, Ionics,

Tokyo, 1987.

9. MC-50 Cyclotron Manual (1984). Scanditronix

10. Reuedi Risler, Jonathan Jacky (Radiation Onclogy Department

University of Washington Seattle ), Technical Description of the Clinical

Neutron Therapy System, Technical Report 90-12-02 Seattle,

WA 98195, USA

11. R.Risler-£]6?l, Routine Operation of the Seattle Clinical Cyclotron

Facility University of Washington Seattle, WA 98195, USA

- 7 3 -

•tf

- 7 5 -

0|£r J

A Study on the Ion Beam Control of Cyclotronusing Intelligent Control

Yu-Seok Kim • Young-Ho Cho • Jong-Seo Chai • Key-Ho Kwon

Abstract - Recently, as the field of cyclotron application is to be wider, to inject the beam where the user want to isgetting more important. But since it is not the easy way to describe the model equation of cyclotron, it could beoperated by only operator's experiences. In this paper, we suggest the cyclotron controller using the fuzzy logic and thegenetic algorithm. The proposed controller was verified in useful by applying to the cyclotron's beam line. In theexperiment the measured results were obtained by VXIbus and the control algorithm was performed byLabWindows/CVI.

Key Words : Cyclotron, Fuzzy Controller, Genetic Algorithm, VXIBus, LabWindows/CVI

1. M B

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1999%

2. s f * l S! Tf£J

(fuzzification), *HTT*! (rule), ^t-(inference)(defuzzification) - f ^ S

7>

chromosome) 5 ^trf-T^fitness function)2}-

search)

°II4[14].

+r -

1Fuzzy ai(rf?|

ra M Alia

-t^Bi—i/ "\ • !

— '

1 si iemFig. 1 Proposed fuzzy and genetic algorithm

7] # ^ , yfe Al^

Fig. 2 Block diagram of proposed algorithm

17> t ^ l : 3-fife

XI°]

Ali

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7>

fe 04

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(1)

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: XH71

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(2)

decimal(x) :

- 7 8 -

Trans. KIEE. Voi. 49, No. 1, 1*J,1999

3. *lfe

3. 1 M

MC-50

34

771] s] ai SJ4.

-^ (Quadrupole lens), fl*!^ ^ ^ H (Steering magnet),

itching magne tos

HI Taraat

3 MC-50

Fig. 3 MC-50 Cyclotron

2-!S-(doublet)

44

Q i

\

— - 1-

F: FocusJnsD: Defocuslng

Fig. 4 Principle of Quadruple lens in the beamline

X,

3. 2

-a a at a,-*

5 a Scroll cHS- eioj5( -M-l-

Fig. 5 Linguistic expression of beam error

s|*l ^-grAli^(fuzzy inference system)^

X,

Positive Big(PB), Positive Medium(PM), Positive

SmalKPS), Zero(ZE), Negative SmalKNS), Negative

Medium(NM), Negative Bi

Fig. 6 Shape of ion beam Fig. 7 Shape of ion beam

(Before modification (After modification

of X axis) of X axis)

64

74

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Table 3. Coding of gene for power supply

a

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2}-,

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H. 1Table 1 Fuzzy rule table of X axis

\xY\

NBNMNSZEPSPMPB

NB

PMPMPBPBPBPMPM

NM

PSPSPMPMPMPSPS

NS

ZEZEPSPSPSZEZE

ZE

ZEZEZEZEZEZEZE

PS

ZEZENSNSNSZEZE

PM

NSNSNMNMNMNSNS

PB

NMNMNBNBNBNMNM

0

0

.710.5700

00

0.71.7100

0

10.8610

0

00

.8611.71.71

00.86001

(3)

w&

u>x • Q2

U>6 : Q3

Table 2 Fuzzy rule table of Y axis 0.5

\xY \

NBNMNSZEPSPMPB

NB

PMPSZEZENSNSNM

NM

PMPSZEZEZENSNM

NS

PBPMPSZENSNMNB

ZE

PBPMPSZENSNMNB

PS

PBPMPSZENSNMNB

PM

PMPSZEZEZENSNM

PB

PMPSZEZEZENSNM

7}

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— Xf,

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- 8 0 -

Trans. KIEE. Vol. 49, No. 1, 131,1999 td

X,

I

11™

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—

1

torA"A*

Cy Y

Fig. 9 Analysis of external input value

IK=fc 4-1-4

Fitnessd) = ^ + H (5)

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Ql, Q2, Q3, X,Ql, Q3 Ql,

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Ql, Q37} ^ ^ t t - fr^l-t-X X O X O

x:

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a 6Table 5 Parameters of genetic

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5

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VXIBus 1 ^E f t 4-8-4^ Ai-ojofl-c- LabWindows/CVI-t

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-81-

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*]• ±0 .

SI4. =1% 12, 13, 14fe

A.

X=17.5mm, Y=17.5mm)

Fig. 11 Convergence of ion error (X=17.5mm, Y=17.5mm)

Fig. 12 Beam distribution of 3D (first data)

Fig. 13 Beam distribution of 3D (sixth data)

Fig. 14 Beam distribution of 3D(nineteenth data)

n U 15 o | $ U 2 x F ° | ^ S S £ (X=17.5mm, Y=17.5mm)

Fig. 15 Convergence of ion beam error

16 O|SHJ S x r ° l t a § £ (X=14mm , Y=14mm)

Fig. 16 Convergence of ion beam error

X=0.1[A], Y=0[A], Ql=10[A],

Q2=20[A], Q3=20[A]S. ^ ^ s l a i , ^-£5l:^ X#=17.5mm,

, o]

OS.

X=0.1[A], Y=0[A],

Q1=15[A], Q2=15[A], Q3=15[A], ^ 5 M X#=14.0mm, Y

#=14.0mmS. - i ^ ^ - ^-f^ldl a f 4 <>1 19^^0)1 .2.2}

- 8 2 -

Trans. KIEE. Vo!. 49, No. 1, 13,1999

4. ^ ^MrnmS.

f-i-

"J 3.7] fi = 14mm,

17*11

fe <* 48.52:,

382: °v

4-8-

r* — --"I •i

(••• •IT] * • , i " • * , " * * ' ^ "1

;- v

17 * i | o p | s | S ^ l u|JIl (X=14mm, Y=14mm)

Fig. 17 Comparison of controller output (X=14mm, Y=14mm)

5.

i, MC-50

Si4.isotope)S.3 3.71 s]

A}S}-(radioactive) 7 r

9X9X7:°} ±7:°} ±0

^ MC-50

[1] R. Westervelt, W. Klein, "Framework for a GeneralPurpose, Intelligent Control System for ParticleAccelerators", Proceeding of the Particle AcceleratorConference and International Conference on HighEnergy Accelerators, IEEE, pp.2175-2177, May, 1995.

[2] J. S. CHA1, Y. S. KIM AND K. H. KWON, "BeamTransport System using Fuzzy Controller in theKCCH Cyclotron", Cyclotrons and Their Applications,Proceedings of the 14th International Conference,pp.310-313, 1996.

[3] S. Clearwater and W. Cleland, "A Real-Time ExpertSystem for Trigger Logic- Logic Monitoring",Proceedings of International Conference on

Accelerator and Large Experimental Physics ControlSystem, November, 1989.

[4] D. Nguyen and M. Lee, "Accelerator and Feedback

Control Simulation Using Neural Networks",SLAC-PUB-5503, May, 1991.

[5] D. Schultz, "The Development of an Expert System to

Tune a Beam Line ", Proceedings of InternationalConference on Accelerator and Large ExperimentalPhysics Control System, November, 1989.

[6] S. Kundu and J. Chen, "Design of Heuristic Fuzzy

Controller", Fifth IEEE Int. Conf. on Fuzzy Systems,pp.2130-2134, 1996.

[7] H. Ishibuchi, K. nozaki and H. Tanaka, "Efficient

fuzzy partition of pattern space for classicationproblem," Fuzzy sets and Systems, vol. 59,pp.295-304, 1993.

[8] E. H. Mamadani, "Application of fuzzy logic to

approximate reasoning using linguistic synthesis",IEEE Trans. Computer, Vol.C-26, nol2, pp.1182-1191,1977.

[9] L. Chambers, Practical Handbook of GeneticAlgorithms, Applications Volume I, CRC Press, 1995.

[10] K. Kristinsson and G. Dumont, "System identificationand control using genetic algorithm", IEEE Trans.System, Man, Cybernetics, vol 22, no. 5,pp.1033-1046, 1992.

[11] J. R. Koza, Genetic programming, MIT press, 1993.[12] Robot T. Cleary, "A New CAMAC and VXIBus

High Performance High Performance HighwayInterconnect", IEEE Transation on Nuclear Science,Vol. 44, No. 3, pp.393-397, June, 1997.

[13] E. J. Barsotti, "The new VME64 ExtensionsStandard, Related VSO and IEEE Standards &VME International Physics Associatdon(VIPA)Activities", Nuclear Science Symposium, Anaheim,CA, Nov. 3, 1996.

[14] W. R. Hwang and W. E. Thompson, "Design of

intellegent fuzzy logic controllers using geneticalgorithms", Proc. of Third EEEE int. conf. on Fuzzysystems, pp. 1383-1388, 1994.

[15] *W*\, 7d-fr*} "MC-50 4 ° l l - a S . § £<§", KAE-RI/MR-298/97, pp. 77-79, 3f«l-7l#^, 1997.

[16] 3-fH!, °1$H, *m*\, ^ 7 l s "VXI A l ^ - i -

pp979-984, 1998.

[17] LabWindows/CVI, National Instruments Corporation,

1996.

6.B2|- 8 3 -

Beam Emittance Measurements Using Alumina Screenat KCCH-MC50 Cyclotron

Shin-ichi Watanabe

Center for Nuclear Study, Graduate School of Science, University of Tokyo

3-2-1, Tanashi-shi, Midori-cho, Tokyo 188-0002, Japan

Jang-Ho Ha, Yu-Seok Em, Hye-Young Lee and Jong-Seo Chai

Cyclotron Application Laboratory, Korea Cancer Center Hospital

Gongneung-Dong, Nowon-Ku, Seoul, Korea

Abstract

The transverse beam emittance of the medical cyclotron KCCH-MC50 in Seoul

was determined from measurements of the beam width on a profile monitor as an

upstream quadrupole field is varied. The beam profile monitor system comprises the

99.5 % alumina with chromium oxide, an industrial TV camera, and an image data

stored system. Using the stored data on the personal computer makes detailed

analysis of the beam profile. The measured beam emittance derived from FWHM of

the beam profile is a good agreement to the designed factory data. In this presentation,

we describe the experimental setup, results, and conclusion of beam emittance.

1. Introduction

A transverse-beam emittance can be measured using the lattice optics of a

transport line and a profile monitor located where the betatron sizes of the beam

dominate. In an example of the quadrupole - drift - profile monitor method, a

quadratic dependence of the beam width is given by

Y=A(k-B)2+ C (1)

Here Fis the square of beam width and kis B'L/Bp of an upstream quadrupole magnet.

The coefficients of A, B, and Care obtained from the quadratic curve fit parameters.

- 8 4 -

The beam emittance i?is given by

(2)

where the factor L is distance between a center of quadrupole magnet and the

fluorescence screen.

Various kinds of beam emittance monitor, which is based on the quadratic

dependence of the beam width, have been developed for the electron machine. [1,2, and

3] These monitors feature the measurement of small emittance beam. The width of

electron beam is sensitive to the strength of upstream quadrupole magnet (lvalue

control) because the electron mass is small compared with ions at the identical magnetic

rigidity. This method is seemed to easy to measure the beam emittance of the electron

beam because an electron gun provides unified beam structure like the single spot beam

source. On the other hand, this method is seemed to difficult to measure the beam

emittance of the multi-charged ion source because of complicated beam structure. Is it

applicable to the large emittance beam such as the beam from the ECR ion source or the

cyclotron ? The INS, University of Tokyo, had been tested the alumina screen using

the 26 MeV Alpha beam [4] because the hardness and chemical property against the

irradiated nuclear beam full fill the operating condition. The alumina screen, which is

the one of the fluorescence screens, has still major contribution to diagnose a density,

width, and center of the nuclear beam at the still low beam current below 10 pA. The

Kyoto group developed the beam emittance monitor for the proton beam, where was

measured by using the alumina screen at the kinetic energy of 50 KeV, 1 MeV, and 7

MeV [5].

The CNS-KCCH group has been promoting the development of the beam

emittance monitor using the alumina screen, which had originally been proposed as the

2nd step of the monitor development following achievement of preliminary test at the

sector focussing cyclotron (K=68) of Center for Nuclear Study, University of Tokyo.

The measurement of beam emittance using the alumina screen was performed at the

medical cyclotron KCCH-MC50 in Seoul (K=50). To measure the beam emittance, CNS

group had provided the alumina screen, data acquisition board, and data acquisition

software. In this presentation, we describe the beam profile monitor using the

alumina screen, beam experiment, data analysis of measured profiles, calculation of

beam optics, and the conclusion of beam emittance. Main contribution to the beam

profile is an uncertainty of the ion source. The lack of uniformity and the

incomprehensible behavior of the ion source are excluded in this presentation.

2. Experimental Setup

The KCCH-MC50 in Seoul, which was built by Scanditronix in 1986, is a variable

energy isochronous cyclotron for acceleration of light ions. The layout of a KCCH-

MC50 cyclotron facility is illustrated in Fig. 1. The parameters of KCCH-MC50 are

tabulated in Table 1. The beam transport line comprises a switching magnet, a

quadrupole magnet family, a gantry system, and beam diagnostic devices. A

switching magnet is used to deliver the beam to the room where is a gantry room, a

target room, and a RI room. The beam diagnostic devices are located at the exit of

cyclotron, the exit of first triplet quadrupole magnets, the exit of the switching magnet,

and the exit of third triplet quadrupole magnets, respectively. The slit and steering

system are provided for the adjustment of the beam center. The cyclotron vault is

separated with radiation shield. The plug system with a carbon shield is located in

the beam transport line to protect the neutron radiation from the cyclotron vault. The

present gantry system provides a straight beam course where is utilized for the beam

application such as the test of beam monitor like the fluorescence screen described in

this paper. The exit of the straight beam course is designed as an isocenter of the

beam transport line.

The experimental setup for the emittance measurement is shown in Fig. 2, where

the alumina screen is located at the down stream of the last quadrupole magnet named

QU8. The distance between the exit of cyclotron (P.) and the alumina screen (P ) is

15.752 m long. The distance between the center of QU8 and the alumina screen is of

5.164 m. The last quadrupole magnet, QU8, is the middle of quadrupole-triplet. The

last of quadrupole-triplet is excluded to play the role of drift space in the beam line. So

the quadrupole - drift - profile monitor structure is realized. The quadratic

dependence of the beam width was measured with the alumina screen.

Alumina is promising for high melting point material under nuclear beam

irradiation because it's high hardness and high chemical stability. The alumina

screen used in this experiment comprises Al2O3+CrC>3 plate of AF995R (Desmarquest)

with 1-mm thickness. The doped oxide chromium plays a role of fluorescence source.

The light spectrum from the AF995R is expected around 700 nm. Physical

characteristics of the AF995R are tabulated in Table 2. The effective area of alumina

screen is designed at 888 mm- but the physical sizes of alumina screen are 50x50 mm2.

The schematic view of the screen monitor is shown in Fig. 3. The alumina screen

is installed in a cubical vacuum chamber of the screen monitor. The side wall of the

vacuum chamber is provided for a view port with a crystal glass of 60 mm-ID. The

- 8 6 -

alumina screen was fixed on a movable rod, which is inserted in the vacuum chamber,

with an angle of 45 degree to the beam direction. The beam profile on the alumina

screen can be observed through the view port. The vacuum chamber was evacuated

up to 10'6 Torr with a turbo molecular pumping system.

An industrial TV camera (ITV) is placed at the gantry room as shown in Fig. 2.

An iris control is made to adjust the light flux reached at the image tube. The room

light in the gantry room is turned off to suppress the background noise on the ITV

signal. An image tube of the ITV is of monochrome type because of the radiation

resistance. The signal processing system is illustrated in Fig. 4. The beam profile

signal is based on the NTSC standard and is connected to an IBM type PC. The IBM

type PC captures a beam profile signal with the aid of an image processing circuit

(AIMS GrabIT Pro) which is the one of the data acquisition boards. An amplitude

resolution of the ADC in the image processing circuit is 8-bit. The digitized beam

profile signal is stored in a graphic memory as a beam profile data. The beam profile

data in the graphic memory is saved onto the hard disc for later detailed study. The

size of the beam profile data stored in the hard disc is chosen at 910 KB with a bitmap

format (BMP). The beam profile data in the graphic memory are displayed

simultaneously on the monitor TV. To show the series of captured beam profiles, eight

pictures are displayed on the monitor TV at once with the aid of a sum-nail function of

the image data processing circuit. It is remarked that the sensitivity of the image

tube used in the ITV is assumed at y=l. The image-processing tool enable us the

correction of the value, y, when the analysis of the beam width has been done.

3. Experiments and image data processing

The experiment was performed using a 50.5 MeV proton beam. The beam

current measured with the faraday cup was 1.5 nA. First, width of the beam

irradiated on the alumina screen was adjusted so that the fluorescence was contained

within an effective area of the alumina screen. Subsequently, the excitation current

of QU8 was chosen at 18.1 A to make a circular beam profile, which was found near the

bottom of the quadratic curve fit, on the associate alumina screen. Then the

excitation current of QU8 was changed to measure lvalue dependence of the beam

profile data. The beam profile data appropriate for the calculation of beam emittance

are saved on the hard disc after the change of excitation current. Some samples of

measured beam profiles are shown in Figs. 5-1, 2 and 3, respectively when the

excitation current of QU8 was chosen at 18.1, 15.1 and 21.1 A respectively.

- 8 7 -

The beam profile data saved on the hard disc were analyzed by using the image-

processing tool in order to measure the beam sizes on the alumina screen. A difficulty

of the image data processing is mathematical processing such as a subtraction of noise

signal from the measured beam profile data. The brightness and quality of the

measured beam profile are influenced by the noise signal, unavoidable beam hallo, and

time structure from the ion source.

The image-data processing tool offers the function to show the three dimensional

(3D) data in X, Y, and Z coordinates. Fig. 6 shows the 3D display of the beam profile

data as shown in Fig. 5-1. The axis X and Z shown in Fig. 6 represent the two-

dimensional coordinates associate with a surface of the alumina screen plate. The axis

Y represents the beam intensity. In Fig. 6, the top of contour map is recognized as a

center of beam profile irradiated on the alumina screen. The tail noise in the beam

profile is taken into account the systematic error of the associate beam width.

The pixel number in the beam profile data gives the beam intensity irradiated on

the alumina screen. For example, Fig. 7 shows that the X and Y-axis represent the

pixel number and the beam intensity, respectively. On the other word, the X-axis

represents a radial direction of the transported beam. A spectrum height, which is

the beam intensity, is a projection of the pixel data along the Z-axis. We can

calculate the beam size by using the digital scale function supported by the image-

processing tool. The tail noise and a fluctuation of the spectrum are to be subtracted

from the original data when a calculation of the beam emittance. Various definitions

of the beam width are in use to calculate the beam emittance. We discuss here the

Gaussian distribution associate with the beam width of the standard deviation a. The

full width at half maximum (FWHM) and the full width at 90 % maximum are discussed

in the following section.

4. Discussions4-1 Beam condition

The beam emittance measurement has been done under the following boundary

conditions; the fluorescence due to the irradiation of the nuclear beam is proportional to

the beam current; the light intensity of the fluorescence is not decreased by experiences

of the medium between the alumina screen and the focussing point of the ITV camera;

the dynamic range of the sensitivity to the light flux is infinitive.

A saturation level of the alumina screen is considered to evaluate the dynamic

range of the alumina screen to the irradiation level of the nuclear beam. A linearity of

the fluorescent flux to the irradiated beam current is estimated. An estimated beam

current excess 250 nA/cnr irradiated to the alumina screen deteriorate a linearity of

fluorescent flux. This estimation is derived from the preliminary test using a 26 MeV

Alpha beam from the sector focussing cyclotron of Institute for Nuclear Study,

University of Tokyo [4]. The beam current of 1.5 nA was chosen at the experiment

using the KCCH-MC50 cyclotron. We assumed that the beam density is flat in the

irradiate area and the beam current is constant during the beam profile measurement.

Thus, the estimated beam intensity is 47.8xlO7 e/mm2 s as the beam current is 1.5 nA.

A recommended lifetime, which is an integrated beam intensity to the unit area, of the

alumina screen is lxlO18 e/mm2. The estimated beam density is 2.5xlO7 e/mm2 s at

the beam sizes of 25 x 15 mm2 on the associate alumina screen. A threshold level from

the view point of the excitation of the fluorescence is lxl07e/mm2 s. So the beam sizes

above mentioned are acceptable area at the beam current of 1.5 nA.

If the lack of data due to a timing coincidence is existed in the measurement

system, signal conditioning circuit is to be used in the experimental setup. We have

had considered the synchronization of the beam profile to the image data processing

circuit. The cyclotron beam gives bunching structure due to the given energy from

the Dee of the cyclotron. A decay time of the fluorescence emitted from the alumina

screen is estimated at 3 x 10'3 sec. We could say that the time periods of the cyclotron

bunched beam is faster than this decay time. This means that the lack of beam profile

data is not occurred during the irradiation of the beam on the alumina screen.

4-2 Beam optics and beam width

To estimate the beam width, using the computer has done the beam transport

simulation [6]. In the calculation, the twiss parameter at the exit of KCCH-MC50 is

assumed that (3x=1.534 m, (3z=3.303 m, ax=0.2138, and ccz=0.6883, where is derived

from the designed factory data of KCCH-MC50. The designed factory data is 4.2 mm,

2.8 mrad, and 11.5 rc-mm mrad for X, X\ and Ex, respectively. The designed factory

data is also 6.8 mm, 2.5 mrad, and 14 7t-mm mrad for Z, Z\ and Ez, respectively. For

convenient, dispersions nx=0.73 m and r\z~0 m, r\xr-0 and T|z'=0, where is the reference

of K68-SF cyclotron at CNS, U-Tokyo, is taken into account the estimation of the beam

envelopes. Using these parameters, the beam width at the alumina screen has been

calculated as the upstream QU8 current is varied. The calculated beam envelopes are

shown in Fig. 8. The beta functions and dispersion functions (twiss parameter) of

the beam transport line are shown in Fig. 9. Figs. 8 and 9 show the example of the

beam optics in case of the upstream current QU8 current is 18.1 A.

The k-value dependence of the measured beam width, which is full width at 90 %

- 8 9 -

maximum, is tabulated in Table 3. Consequently, we gave the beam width of 11.3 mm

in X-direction and the beam width of 13.05 mm in Z-direction, respectively. These

values are not agreement to the calculated beam width. We should note that the beam

profile monitor does not cover the exact beam width at 90% maximum because the beam

acceptance of the transport line is small compared with expected acceptance area.

Unfortunately, the beam is prevented with the slit element located at the upstream of

the profile monitor in the beam transport line. Then the true k-value dependence

could not be measured because the tails of the spectrum, which was involved in the full

width at 90 % maximum, was disappeared by prevention of the transported beam.

The quadratic dependence of the beam width, which is defined by the FWHM, is

tabulated in Table 4. The measured beam width as a function of lvalues is shown in

Fig. 10. In the Fig. 10, the curve fit lines of the square of the beam width, Krand Yz,

are shown.

4-3 Beam emittance

The beam emittances Ex and Ez are given by the equations (1) and (2),

respectively. The coefficients, A and C, are derived from the quadratic equation of

beam width, YxanA Yz, in the Fig. 10. The parameter Lj$%. 164 m between PI and QU8

as shown in Fig. 2. The beam emittance calculations give the values of Ex= 7.5 and

Ez = 10.3 rc-mm mrad, respectively. These emittances are fairly good agreement to

the designed factory data of 11.5 and 14 rc-mm mrad, respectively. On the other hand,

we should note that the difference between the designed factory data and the measured

beam emittance Ex of 21.4 rc-mm mrad, for example, which was derived from the full

width at the 90 % maximum.

The reason is discussed as follows; the parameter A in the equation (1) mentioned

in the previous section, depend on the quadratic force influenced by the upstream

quadrupole magnet QU8; the parameter A represents the <7o2i?12

2, where the ao and Rvl

are the beam size in the upstream quadrupole magnet of strength k and the transfer

matrix element between the quadrupole and the alumina screen, respectively. In the

equation (1), the parameter B represents the k0 where is the quadrupole strength at the

minimum of the parabola. The parameter C represents the erR^la*. If the

parameter ao is influenced by any reason at the upstream of QU8, we could not

determine the precise beam width at the alumina screen.

The detailed discussion is found [2]. The measured beam emittance em is given

by,

- 9 0 -

— ' * }. f' (3)

where the crsys and the er are the system resolution and the actual beam emittance,

respectively.

The system resolution, asys, is good in the present experiment because of 8 bit

resolution of ADC in the image processing circuit. Then the first term in the square

root becomes small values compared with actual beam emittance, £r Thus the

measured emittance becomes near e,. The beam width derived from the FWHM is not

including the tails region of density distribution where is prevented by the insertion

devices such as the slit and collimator. So, the calculation of the beam emittance

using the FWHM gave the actual beam emittance.

5. Summary

The quadratic dependence of the beam width was measured at the KCCH-MC50

cyclotron. The summary is as follows: We show the beam profile data measured with

the alumina screen, Al2O3+CrC>3 plate of AF995R (Desmarquest) with 1-mm thickness.

The extracted beam current is 1.5 nA protons at 50.5 MeV. The beam profile was

measured with ITV camera system and was analyzed with the image processing tool.

The beam profile data was evaluated to determine the transverse beam emittance

according with both the projections where the full width at 90 % maximum and the

FWHM. The measured beam emittance based on the beam width of FWHM is a good

agreement to the designed factory data of Ex = 11.5 and Ez = 14 7r-mm mrad,

respectively.

6. Acknowledgments

The authors wish to thank the cyclotron crew of the KCCH-MC50 cyclotron

application laboratory for their helpful operation. The first author thanks Prof. Y.Shida

for his valuable comments and discussions. This work was supported in part by

grant-in-aid for Joint Research Project under The Japan-Korea Basic Scientific

Promotion Program (KOSEF-JSPS).

-91-

References

[1] M. C. Loss et al., "Automated Emittance Measurements In The SLC",SLAC-PUB-

4278, March 1987 (A)

[2] M. C. Loss etal, "High Resolution Beam Profile Monitors In The SLC", Transaction

of Nuclear Science, Vol.NS-32, No.5, Oct. 1985.

[3] Y. Hashimoto et al.,"Beam Profile Monitor Using Alumina Screen And CCD

Camera" INS-T-511, Aug. 1992.[4] S. Watanabe et al. "Beam-Profile Measurement with an Al2C>3+Cr Plate", Annual

Report 1994, INS Tokyo-University, pp25-26.

[5] T. Shirai et al., "Emittance Monitor With View Screen And Slits", Proc. of Linac'94,

Japan, 1994.

[6] Phil Bryant, CERN, private communication, http://nicewww.cern.ch/~bryant

- 9 2 -

Table 1. The Characteristics and Specifications of MC 50 Cyclotron

General

Accelerating particles

P

d

G

H e - 3

Pole diameter

Minimum gap

Maximum gap

Sectors number

Spiral angle in degrees

Circular trim coils

Maximum average field

Minimum average field

Maximum hill field

Magnet field stability

Energy

20 ~ 50 MeV

1 0 - 2 5 MeV

25 ~ 52 MeV

20 ~ 70 MeV

Magnet system

143 cm

11 cm

19.7 cm

3

. max. 55

10 pairs

17.5 kG

10.5 kG

20.5 kg

1 X 10 5

Beam intensity

60 pA

30 pA

30 pA

20 pA

RF system

Dees

Width in degrees

Minimum aperture

Frequency range

Frequency stability

Dee tuning by movable short,

mode

Dee voltage (maximum)

Dee voltage stability

2

90°

2.0 cm

26.8 to 15.5 MHz

lO'6

U4

40 kV

< 10 "3

- 9 3 -

Table 4. K-value dependence of the measured beam width ( FWHM)

K m4.9315.1175.1785.238

5.35.425.54

5.6025.6635.725.84

5.9656.0256.3286.449

K*L m'0.739650.767550.77670.7857

0.7950.8130.831

0.84030.84945

0.8580.876

0.894750.90375

0.94920.967

Yx-FWHMpia714950

50.547

40.53434

32.533344468

112118

Yz-FWHMpii124.5

7666

64.549363434

36.538445658

78.593

Yx-FWHM mn14.29.810

10.19.48.16.86.86.56.66.88.8

13.622.423.6

Yz-FWHM mm24.915.213.212.99.87.26.86.87.37.68.8

11.211.615.718.6

(Yx/2)2 mm2

50.4124.01

2525.5

22.0916.4

11.5611.56

10.56310.8919.3631.3646.24

125.44139.24

(Yz/2)' mm2

15557.7643.5641.6

24.0112.9611.5611.56

13.322514.4411.5619.3633.64

61.622586.49

Cyclotron Facility of KCCH

Fig. 1. Layout of KCCH-MC50 cyclotron facility. Alumina screen is located at the

end of beam course in the gantry room.

- 9 4 -

Table 2. Specifications of the fluorescence screen

Main Constitution

Melting point

Absolute density

Coefficient ofthermal expansion

Specific heat 20 < T < 1000 CD

Dielectric strength

Electric resistively

Relative sensitivity

Lifetime

(Activator Cr)

1850 CD

3.98

8.6xlO'6

1.09 J/cm.s.CD

30-35 kV/mm

lxlO7 e/mm^.s

lxlO18 e/mm2

Table 3. K-value dependence of the measured beam width (90% maximum)

Km"2

4.9315.1175.1785.2385.35.425.485.545.6025.6635.725.845.9656.0256.328

K*L m~'0.739650.767550.77670.78570.7950.8130.8220.8310.84030.849450.8560.8760.894750.903750.9492

Yx-90% pix10384807771.56356.55054.55455698698172

Yz-90* pix16312710610180.56165.25606C.5606369788092

Yx-90% mm20.616.81615.414.312.611.31010.910.81113.817.219.634.4

Yz-90% mm32.625.421.220.216.112.213.051212.11212.613.815.61618.4

(Yx/2)2 mms

106.0970.566459.2951.122539.6931.922529.702529.1630.2547.5173.9696.04294.84

(Yz/2)2 ram1

265.69161.29112.36102.0164.802537.2142.5753636.60253639.6947.6160.846484.64

- 9 5 -

The 4th Korea- laoan Joint Symposium on Cyclotrons and Nuclear Science

Neutral Pion Photoproduction on the proton near threshold

E-Tong CheonDepartment of Physics, Yonsei University, Seoul 120-749

Moon Taeg JeongDepartment of Physics, Dongshin University, Naju 520-180

Abstract

Recently, considerable interest was drawn on the neutral pion photopro-ductioin on the proton near threshold in the context of violation of the low-energy theorem(LET).

The value of the electric dipole amplitude predicted by LET is Eo+ =-2.27 x 10~3ro~+, while the measured value is Eo+ = (-1.31 ± 0.08) x10-3m^.

This difference might be explained by taking the vector meson contri-butions into account. However, the key point of this problem is whether aunitary cusp behaviour due to the virtual process, yp —• 7r+n —> nop, aroundthe 7r+-threshold exists or not.

In this paper, we calculated the EQ+ and Mj± amplitudes of 7p —>• pn°reaction taking vector meson contributions into account in the pole model of t-channel. Our results are Eo+ = —0.51 x 10~3m~+, Mx+ = (7.56 x 10~3m~+)kgand Mj- = (-2.15 x 10~3m-?)kg.

analysis of the angular distributions, we are led to a conclusionthat the experimental results cannot be explained without the virtual process.Namely, we insist on existence of the cusp.

- 9 6 -

The 4th Korea- Taoan Toint Symposium on Cyclotrons and Nuclear Science.

Compact cyclotrons for medical application

Hajime SaitoQuantum Equipment Business Center, Sumitomo Heavy Industries, Ltd. 9-11

Kitashinagawa 5- chome, Shinagawa-ku, Tokyo, 141-8686, Japan

Abstract

Sumitomo Heavy Industries(SHI) has been active in the field of particleacceleration since 1970, and delivered an extensive series of accelerator sys-tems of electrons and ions of energies ranging from a few hundred keV toseveral hundred MeV. Recently, Compact AVF cyclotrons have been devel-oped and are added in the product line for the application in the medical field.Negative-ion cyclotrons named HM-18 and HM-12 are for production of ra-dio isotopes, Carbon-11, Nitrogen-13, Oxygen-15 and Fluorine-18 to be usedin Positron Emission Tomography (PET). HM-18 produces 18MeV protonsand lOMeV deuterons , and HM-12 does 12MeV protons and 6MeV deuterons.Fixed energy proton cyclotron C-235 is for cancer treatment, supplies 235MeVprotons in the beam current over 500nA, and has been developed under thejoint cooperation with Ion Beam Application (IBA), Belgium. The designconcept and running performance of these machines will be presented .

- 9 7 -

The 4th Korea- laoan foint Symposium on Cyclotrons and Nuclear Science

Design of RF System for a new PET Cyclotron

Jang Ho HAKorea Cancer Center Hospital, Korea Atomic Energy Rearch Institute, Seoul,

Koreae-mail: jang@kcchsun.kcch.re.kr

Abstract

We design the RF resonator system for a new PET cyclotron dedicatedPET tracer isotope production. The dimension of RF cavity and dee is de-termined by the effective j wave method with the zero-impedance at a 72MHz frequency. The cavity design is specified that the R.F. is 72 MHz, thepower is 10 kW, dee voltage is 40 kV, dee angle is 43.6°, dee length is 50cm. We designed the resonator with consideration of the dee-liner distanceand co-axial cavity length. The dee designed by perfoming three type of sys-tem calculation that they shows different capacitance between dee and liner.The coupling mode is inducetive coupling. The test bench of RF system wasinstalled and will test.

- 9 8 -

The 4th Korea- Japan Joint Symposium on Cyclotrons and Nuclear Science

Upgrading of Cyclotron Control System

S. WATANABE, Y. OHSIRO, N.YAMAZAKI, H.MUTO, S.KUBONO, Y. SHIDA,T.KATAYAMA, and M.SEKIGUCHI

Center for Nuclear Study, Graduate School of science, The University of Tokyo,Midoricho 3-2-l,Tanashi, Tokyo 188-0002, Japan

watasin@cns.s.u-tokyo.ac.jp

Abstract

The most the existing cyclotron facilities are constructed for the nuclearexperiments, medical applications, and industrial applications. Especially,advanced cyclotron facility covers either the many application fields or thededicated field such as the medical application. Prom my view point, meaningof advanced cyclotron facility provides the features relevant to high qualitybeam, variety of ion species, and high current beam sources. The coupledworks relating with accelerator science and beam technology are main part ofthe upgrading of cyclotron facilities. For examples, Cyclotron with K-numberof 68 at CNS (Center for Nuclear Study, The University of Tokyo) is devotedfor improving the ion source, external injection system, rf system, control sys-tem, and beam diagnostic system. These works excepts the ion source havebeen done from the following point of view; improvement of beam optics of ex-ternal injection system aiming at highest transmission efficiency; improvementof operating performance of present cyclotron assisted by advanced computertechnology; and development of beam diagnostic system based on the ad-vanced accelerator technology. The computer control system is a frameworkof the advanced cyclotron facility and their relative importance is increasedin accordance with a variety of cyclotron facilities. The most advanced com-puter technology such as WWW enable us seamless cyclotron control with theaid of multimedia technology. The data logging, image data processing, andbeam diagnostic system have been developed to study the newest cyclotroncontrol system. The developed system enable us browsing the operation sta-tus of CNS cyclotron by using the personal computer linked with local areanetwork. The developed system is applicable to radiation safety control be-cause of distributed radiation detector and safety check system. The presentpaper discusses the applied WWW technology relating with CNS cyclotronfacility. The paper also discusses the study of beam diagnostic and controlrelevant to the improvement of external injection system.

-99-

The 4th Korea- loom Joint Symposium on Cyclotrons and Nuclear Science

The design of the PIG ion source for the negative hydrogen.

Hyeyoung Lee1, S.A.Shin1, S.Oh2, M.Yoon2, J.S.Chai3, J.H.Ha3

1) Department of Physics, Ewha W.Univ.,Seoul2) Department of Physics, POSTECH

S) Cyclotron Application Lab.,KCCH-KAERI

Abstract

A Penning Ionization Gauge (PIG) ion source is constructed to producean intense H~ beam. The purpose of our investigation with this source is todevelop an H~ PIG source with a significantly smaller dimension in geome-try so that the final version of this source will be comfortably placed in thecentral region of the PET cyclotron which is under construction. This reduc-tion in dimension is expected to improve the overall performance of the PETcyclotron. As the cathode material we use LaB6- The ion source is placedat the center of non-magnetic stainless steel vacuum chamber with an innerradius of 140 mm and then the chamber itself is inserted in the space betweenthe top and bottom magnet pole. For a visual investigation of the sourceperformance, the chamber has two see-through windows. Attainable vacuumpressure, when the gas is turned off, is 5xlO~6torr. The magnetic field issimulated using the POISSON-2D and then TOSCA-3D. The excitation coilis of a borrow copper conductor type, the dimension of which is determinedafter the consideration of generation and the pressure drop of the cooling wa-ter. H~beam has been observed with an arc power of 2kV,lA. The extractionvoltage is positive 17kV. Theoretical calculations for the trajectories of ionsfrom the anode slit to one extractor electrode are carried out to find the op-timum position and width of the extractor slit. They indicate that the slithas to be at least 2.0mm wide with its center shifted towards the Faradaycup by 1.0mm. A Faraday cup is constructed and installed inside the cham-ber. The cup can be biased to positive 50V to prevent secondary electronsfrom escaping. After solving the initial problems of high voltage breakdownsand sparking in the cathode-anode region of the source, we finally succeed incollecting the negative ions in the Faraday cup.

-100-

The 4th Korea- Japan foint Symposium on Cyclotrons and Nuclear Science

Stellar 13C(a,n)16O reaction studied by the 13C(6Li,d)17O reaction

S. KatoT°) K. Abe,a'6) S. Kubono,*> X. Liu,6) T. Minemura,^ P. Strasser,c)M. Kurokawa,c> C. C. Yun,6> K. Kumagai,^ T. Matsumura,*) N. Imai,6)

Y. K. Kwon ^ J. H. H&V C. S. Lee*) Y. K. Kim,*> and C. Lee&>

a) Department of Physics, Yamagata University, Yamagata, 990-8560 JapanE-mail: kato@sci.kj.yamagata-u.ac.jp

b) CNS, University of Tokyo, Tanashi, Tokyo, 188-0002 Japanc) RIKEN, Wako, Saitama, 351-0198 Japand) Department of Physics, Rikkyou University, Tokyo, 171-8501 Japane) Department of Physics, Tohoku University, Sendai, 980-8578 Japanf) Department of Physics, University of Tokyo, Tokyo, 113-0033 Japang) Chun-Ang University, Koreah) Seoul National University, Korea

Abstract

The slow-neutron capture process (s-process) plays an important role forthe synthesis of elements heavier than iron. On the a-burning shell of redgiants, the neutrons are produced by the 13C(a,n)16O reaction

Because the temperature of the reaction site is 0.1 — 0.2 GK, the astro-physical S factor at low energies is very important for the derivation of thereaction rate. If the sub-threshold state (6.359 MeV state in 17O which is0.003 MeV below the cH-13C threshold) has a large a-component, a drasticincrease of the S factor at the low energy region can be expected. This isthe reason why many efforts have been devoted to the measurements of thecross sections at energies as low as possible. Although the measurements upto now seem to suggest the existence of an effect of the sub-threshold state,the uncertainty in the cross section of the 13C(a,n)16O reaction at low energyis too large for the existence to be conclusive.

Since an improved measurement of the compound nuclear process of the13C(a,n)16O reaction at much lower energies is impractical, we tried an al-ternative way to deduce the astrophysical S factor through the a-transferreaction on 13C which leave the excited states of 17O in the residual nucleus.We measured angular distributions of the 13C(6Li,d)17O reaction at 60 MeVwith the high-resolution spectrometer. We were able for the first time toseparate the peak of 6.356 MeV state in 17O from the 6.917 MeV state in16O originated from the 12C contaminant in the target of 13C. By the DWBAanalysis, we extracted the a spectroscopic factor of the sub-threshold 6.356MeV state. The result (Sa = 0.042) shows that the sub-threshold state hasa small effect on the astrophysical S factor and on the reaction rate at thetemperature of the neutron production.

-101-

The 4th Korea- Taoan Toint Symposium on Cyclotrons and Nuclear Science

a-decay Branching Ratio Measurement of 19Ne States and ResonantParticle Decay Spectroscopy.

Chnaghack LeePhysics Department, Seoul National University, Seoul, Korea

Abstract

Nuclear reactions on possible breakout processes off the Hot-CNO (HCNO)cycle are of great interest in nuclear astrophysics. An interesting question hereis if CNO material is really transmuted into heavier elements in explosivephenomena such as novae. The reaction sequence of 15O(a,7)19Ne(p,7)20Nais considered to be one of them to be the limiting reaction for ignition of therp-process at the time. However, the reaction rate of this reaction has beendetermined experimentally at the temperature region of interest.

Traditional method to measure the a-decay coincidence by using the lighterbeam and heavier target, however, gives several difficulties to enhance thequality of the data. Since the center-of-mass system of 19Ne a-decay is al-most at rest, a large solid angle is required to be covered with many silicondetectors to enhance the statistics. Even if the solid angle is enoughly largeto get the statistics, the coincident a-particles, especially from the 4.033 MeV19Ne state, carry too low energy about 300 keV to be resolved clearly fromthe electronic noise and to pass through the gold layer in the front of thedetector. Even target thickness is limited to be enlarged for the enhancementof the statistics since the outgoing triton energy resolution is quite dependenton the target thickness.

Resonant Particle Decay Spectroscopy (RPDS) [1] is a possible solutionto entangle the problems mentioned in the previous section. A previous ex-periment to investigate high resolution property of RPDS [2] proved that itis a nice technique to resolve the particle decay states barely above thresh-old. It suggested that the energy loss and straggling in the target affect littleto the resolution of the final decay energy reconstructed from the measuredvalues. With reasonably selected geometry of detector alignment and beamenergy RPDS also provides a great deal of effective solid angle in the center-of-mass system. Usually heavier particles are accelerated in measurement ofparticle-decayable states in various nuclei, a-decayable states in 15N, UCand 13C states have been populated with high resolution and the alpha-decaycross-sections of these states have been measured successfully using the RPDStechnique. [3, 4, 5] RPDS is possibly applied to populate the 4.03 MeV and4.55 MeV states in 19Ne, and it will give a solution to entangle the questionregarding the break-off HCNO cycle.

-102-

The 4th Korea- Japan Joint Symposium on Cyclotrons and Nuclear Science

Measurement of Excited States in Al for Astrophysicai Interest

X. Liua, S. Kubonoa, T. Teranishia, C. C. Yuna, K. Abea-b, K. Kumagaia'c,P. Strasser4, S. Katob, N. Imaie, and Y. Yamamotoa

a) Center for Nuclear Study (CNS), University of Tokyo, Tanashi, Tokyo, 188-0002Japanbj^Department of Physics, Yamagata University, Yamagata, 990-8560 Japanc)Department of Physics, Tohoku University, Sendai, Miyagi, 980-8578 Japand)RIKEN (The Institute of Physical and Chemical Research), Hirosawa, Wako,Saitama, 351-0198 Japane)Department of Physics, University of Tokyo, Tokyo, 113-0033 Japan

Abstract

The nuclear astrophysical reaction 22Mg(p,7)23AI is important to under-standing the production of 22Na in neon Nova. To evaluate the reaction rateof this reaction, we measured the excited states in 23A1 by the multinucleontransfer reaction 24Mg(14N,15C)23Al at Elab = 113 MeV with a focal plane de-tector system that was developed to measure reactions that have low yields.This detector system provides high resolution energy signal by large area sili-con detectors, and information on particle orbits by two position counters. Inthis talk, we present the experimental techniques, as well as the preliminaryexperimental results.

103-

The 4th Korea- Japan Joint Symposium on Cyclotrons and Nuclear Science.

Status Report of the KCCH-Cyclotron Operation and Development

Jong-Seo CHAIKorea Cancer Center Hospital, Korea Atomic Energy Rearch Institute, Seoul,

Koreae-mail: jschai@kcchsun.kcch.re.kr

Abstract

The MC-50 built first in Korea is a variable energy isochronous cyclotronfor the acceleration (up to 50 MeV) of light particles, which can be used inthe fields of nuclear medicine, physics, biology and engineering. Efficient op-eration of AVF MC-50 cyclotron has an important influence on not only theexecution of MOST(Ministry of Science and Technology) project which aremainly on the researches for the metal material and radionuclide development,the evaluation of exposure to U3Si, the research for effect on proton irradia-tion to Zr material but also radioisotope production and neutron irradiation.The objectives of the project are chiefly to support the above mentioned, tocontribute to promotion of the cyclotron operation and development for main-tenance technology and to build up the fundamental data of beam extractionfrom cyclotron. Therefore it is required to increase the cyclotron reliabil-ity and to decrease the failure rate by the preventive maintenance, efficientoperation and prompt solution of general problems.

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The 4th Korea- Japan loint Symposium on Cyclotrons and Nuclear Science

A Pre-Injector RFQ and a "Charge-State Multiplier" System of theRIKEN Heavy Ion Linac

0 . Kamigaito, M. Kase, A. Goto, Y. Miyazawa, T. Chiba, M. Hemmi, S. Kohara,E. Ikezawa, and Y. Yano

The Institute of Physical and Chemical Research (RIKEN) Wako-shi, Saitama,351-0198 Japan

e-mail:kamigait@ringps.riken. go.jp

Abstract

Construction of the RI (radio-isotope) beam factory has been started inRIKEN, which aims to increase beam energies up to 400 MeV/u for lightheavy-ions and 150 MeV/u for very heavy ions using a cascade of two ringcyclotrons as a booster of the present K540-MeV ring cyclotron (RRC). One ofthe main purposes of the project is to produce RI beams and/or new isotopesin the whole range of nuclear masses up to uranium. In order to achieve thegoal, it is indispensable to increase the intensity of heavy ion beams from thefrequency-variable Wider BSP B linac (RILAC), one of the inje ctors of theRRC.

As the first step to meet the demand above, a pre-injector system con-sisting of an RFQ and an 18-GHz ECR ion source was constructed for theRILAC in 1996. The RFQ, based on a new type of "folded-coaxial" resonator,accelerates ions with a range of mass-to-charge ratio (m/q) from 6 to 26 in thecw mode, by varying the resonant frequency from 17.4 to 39.0 MHz. The out-put energy is 450 keV/q, which is equivalent to the maximum voltage of thetwenty-years-old Cockcroft-Walton injector. The beam intensity of low energyions has remarkably increased since the installation of the pre-injector. Forexample, the intensity of argon and xenon beams extracted from the RRChave reached 2000 and 500 pnA, respectively, in the energy range from 8 to24 MeV/u.

On the other hand, charge-stripping after the RILAC is still necessary forhigh energy beams of heavy ions. However, the output energy of the RILAC istoo low to generate highly charged ions which could be acceptable in the fol-lowing ring cyclotrons. Therefore, a "charge-state multiplier " system (CSM)has been proposed, which is a combination of an accelerator, charge-stripper,and decelerator. The accelerator section increases the stripping energy furtherand the decelerator section brings the beam energy down to the initial valueafter charge-stripping. Total voltage-gain required for the accelerator and de-celerator sections are 25.6 and 12.5 MV, respectively. For the accelerator anddecelerator sections, drift tube linacs of variable-frequency type will be used.The low energy section of the CSM, consisting of two accelerator tanks andone decelerator tank, is under construction.

- 1 0 5 -

The 4th Korea- latxtn Joint Symposium on Cyclotrons and Nuclear Science

KOMAC H~ Beam Extractor for Cancer Therapy

Hyo Eun AhnKorea Atomic Energy Research Institute, P.O. Box 105, Yusong, Taejon, Korea

305-600email: heahn@nanum.kaeri.re.kr

Abstract

New scheme for a beam extraction is developed to extract a=20 negativehydrogen ion beam at 260 MeV from the KOMAC=20 (Korea Multi-purposeAccelerator Complex) linear accelerator, which produce both 18 mA protons(H+) and 2 mA negative hydrogen ions (H~)=20 with energies up to 1 GeV.The negative hydrogen ions are extracted by a stripper magnet and the=20un-extracted ions are returned to the linac. The main feature of this extractoris its ability to regulate the intensity of the extracted beam with the strippermagnet. The extracted 260 MeV beam will be used=20 for cancer therapy.

106-

The 4th Korea- Taoan Toint Symposium on Cyclotrons and Nuclear Science

High Current Heavy Ion Cyclotron System

Takeshi KatayamaCenter for Nuclear Study, School of Science, University of Tokyo

Beam Physics and Engineering Laboratory, RIKEN

Abstract

To develop a new phase of low energy heavy ion physics, it is intensivelydiscussed at CNS to construct a high current heavy ion cyclotron acceleratorsystem. The target specification of new accelerator system, is 6MeV/u forXenon ion with average current 1 puA, and lOMeV/u for Oxygen ion withcurrent of 100 puA. To accelerate such high current ion beam in the cyclotronsystem, it is found that the main accelerator should be separate sector cy-clotron with K number 110, and the injector for that cyclotron should be aRF quadrupole linac. The main reasons of this selection are; to compensatethe space charge problem in the injection energy at cyclotron, the injectionenergy should be high enough, and secondly to assure the high extractionefficiency from the cyclotron the turn separation should be large enough. Theaverage magnetic field is set at relatively low and the RF acceleration voltageis high. To install the two RF cavities and extraction devices, the separatesector cyclotron is a most promosing candidate.

In this report we will describe the details of design of cyclotron+RFQinjector system as well as the space charge problems in the beam transportline, cyclotron and RFQ linac.

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The 4th Korea- Japan Joint Symposium on Cyclotrons and Nuclear Science

Accel-decel strong focusing for tandem accelerator

K. Sagara, H. Okuda, T. Nakashima, N. Ikeda, and S. MorinobuDepartment of Physics, Kyushu University, Fukuoka 812-8581, Japan

e-mail: sagara@nucl.phys.kyushu-u. ac.jp

Abstract

Astro-nuclear reactions take place at low energy and their cross sectionsare very small due to Coulomb barrier. To make direct measurements ofsuch reactions we need very high-intensity low-energy beams together withhigh-efficiency detectors and particular targets.

Kyushu University tandem accelerator has the maximum erminal voltageof 10 MV, and the beam transmission is heavily deteriorated below a fewMV. A new method of accel-decel strong focusing was thought out to increasethe transmission of low-energy beams. In the normal operation the electricpotential of the beam goes up uniformly from the earth level to the terminalpotential V. In the new accel-decel operation, the beam potential goes up toV in a short length (=1/5 of the total length), then goes down to V/4 in thesame short length, again goes up to V and down to V/4, finally goes up to V.The beam is focused, defocused, focused, defocused, and focused. As a whole,the beam is strongly focused, and the beam transmission is highly increased.

We have tested the accel-decel method using Kyushu University tandemaccelerator. The accel-decel method was applied to both the low-energy andhigh-energy sides of the accelerator. For the terminal voltage of 1 MV thetransmission of the carbon beam was 45which was 10 times higher than thetransmission in the normal mode. The electric current to maintain the ter-minal voltage was about 20 times more in the accel-decel mode than in thenormal mode. The large current is advantageous to stabilize the terminalvoltage. The accel-decel mode and the normal mode can be easily exchanged.

For the actual acceleration of high-intensity low-energy beam, a large-aperture gas stripper is under construction.

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The 4th Korea- Tavan Joint Symposium on Cyclotrons and Nuclear Science

A feasibility study for low energy 7Be beam extraction

Yeongduk KimSNU-AMS collaboration

Department of Physics, Sejong University, Seoul, Korea

Abstract7Be(p,'y)&B reaction has been one of the key uncertainties in the solar

neutrino problem. There are several experimental data down to 100 KeV in-cluding most recent experiment done at Bordeaux in Prance[l]. Through therecent meeting and publication [2], the experts in the solar neutrino problemrecommended the <Si7(0) factor to be 19*2e^> 15 % smaller than the previousrecommended value after reexamining the recent experimental and theoreticalworks. An Italian group(NABONA collaboration) recently tried to performa reverse kinematic reaction using 7Be beam in an attempt to avoid prob-lems in the all previous experiments with 7Be target [3]. We have preformeda feasibility study to use the KCCH cyclotron and SNU-AMS facility to ex-tract low energy 7Be beam with appropriate beam intensities. Li2O powdertarget was irradiated about 3 hours with 20 MeV proton beam at KCCH,and the irradiated powders were used as a sputtering target at SNU-AMS.We didn't try to separate 7BeO from 7LiO yet, and simply measured the478 KeV 7 intensities after selecting the mass 23 particles just before acceler-ator tank. The extraction efficiency from the sputtering source will presented.

References1. F. Hammache et al., Phys. Rev. Lett. 80, 928 (1998)2. E.G. Adelberger et al., Rev. Mod. Phys. (1998)3. L. Campajola et al., Z. Phys. A 356, 107 (1996)

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The 4th Korea- Japan Joint Symposium on Cyclotrons and Nuclear Science

A Microscopic Understanding of the Nuclear Structure— from BCS to Hartree Fock Bogoliubob Theory

Myung Ki Cheoun and Il-Tong CheonDepartment of Physics, Yonsei University, Seoul 120-749, Korea

E. mail : cheoun@phya.yonsei.ac.kr and itcheoun@phya.yonsei.ac.kr

Abstract

The Hartree-Fock (HF) method provides a tool for understanding the av-erage potential, for instance, shell model in terms of an effective N-N interac-tion. This method takes the long-range part in the interaction into account.Since this long-range part corresponds to particle-hole (p-h) interactions, thereremained short-range particle-particle(p-p) interactions as the residual inter-action in the mean field. Bardeen-Cooper-Schriffer (BCS) method, which in-corporates the p-p correlation, has been successful to describe the open shellnuclei. Hartree-Fock-Bogoliubob (HFB) method is the model unifying theseHF and BCS methods. Therefore it is a very attractive method in theoreticalside. Moreover its frame can include the pairing interaction in different isospinand angular momentum states in the non-diagonal form. In case of the isospin,therefore, it can describe not only proton-proton, neutron-neutron, but alsothe neutron-proton paring correlations [Ref.l], which cannot be included inthe conventional BCS method. For the cases of the angular momentum, itcan deal with the exotic nuclei, where the paring in different states are im-portant ingredients. In specific, in the neutron-rich nuclei, which is importantin astronuclear physics because of the r-processes , HFB approach is said[Ref.2] to explain the formation of neutron halo. We review these two resultsand discuss the possibility of extending these approaches to the microscopicunderstanding the exotic nuclei.

Ref.l Myung Ki Cheoun, et.al, Nucl. Phys., A587, 301 (1995).Ref.2 W.Poeschl, et.al, Phy. Rev. Let., 79, No20, 3841 (1997).

-no-

The 4th Korea- Taoan Toint Symposium on Cyclotrons and Nuclear Science;

Effects of the Vector Mesons on the Neutral Pion Photoproduction by3 He Nucleus

Moon Taeg JeongDepartment of Physics, Dongshin University, Naju 520-714, Korea

Il-Tong CheonDepartment of Physics, Yonsei University, Seoul 120-749, Korea

Abstract

Taking into account the t-channel vector meson exchange, we have calcu-lated the differential cross section for the neutral pion photoproduction on theproton and nucleus zHe. For the proton, we have used the Blomqvist-Lagetamplitude [1], and for nucleus 3.ffe, we have used a 3-body wave function[2] ob-tained by solving the Faddeev equation with the Bonn potential and the pion-nucleus optical potential, computer program LPOTT [3] which gave a gooddescription for the differential cross section of the process 3i?e(7r±,7r:fc)3iye.It is shown that the differential cross section for the 3He(j, 7r°)3/fe reactiondepends largely on the effective vector meson-nucleon coupling constant g*modified in the nuclear medium without changing those for the 3He(y, -Kreaction .

References[1] I. Blomqvist and J. M. Laget, Nucl. Phys. A280, 405(1977).

[2] Kr. T. Kim et al., Phys. Rev. C38, 2366(1988).

[3] R. H. Landau, Comput. Phys. 28, 109(1982).

I l l -

BIBLIOGRAPHIC INFORMATION SHEET

Performing Org.

Report No.

Sponsoring Org

Report No.

Standard Report

No.

IMS Subject

Code

KCCH/MR-021/99

Title/Subtitle

MC-50 AVF cyclotron operation

Project Manager and Dept. Kim Yu-Seok (Cyclotron Lab.)

Researcher and Dept

Chai Jong-Seo(") Bak Seong-Ki(") Park Chan Won(")Jo Young Ho (") Hong Seong-Seok (") Lee Min-Yong (")Jang Ho Ha(")

Pub. Place Pub. Org. KCCH, KAERIPub.

Date2000.1

Page 66p Fig. Table Yes( O ), No( Size

Note

Classified Open(O), Outside( ), Class Report Type Operating Report

Sponsoring Org. Contract No.

Abstract (About 300 Words)

The first cyclotron in Korea, MC-50 cyclotron is used for neutron irradiation, radionuclidedevelopment,production and material and biomedical research. 50.5MeV and 35MeV protonbeam have been extracted with 20-60M- A total of beam extraction time are 1095.7 hours.206.5 hours are used for the developments and 663.8hours are for radionuclide productionand development and 225.4 hours for application researches. The shutdown days are23days.Fundamental data for failure decrement and efficient beam extraction were composedand maintenance technologies were developed.

Subject Keywords (About 10 Words)

cyclotron operation, maintenance,proton, accelerator, radioisotope

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