TENSOR POLARIZED DEUTERON BEAM AT THE NUCLOTRON

Yu.K.Pilipenko, V.P.Ershov, V.V.Fimushkin, A.Yu.Isupov, L.V.Kutuzova, V.P.Ladigin, N.M.Piskunov, V.P.Vadeev, T.Vasiliev, L.S.Zolin

Joint Institute for Nuclear Research, Dubna,

Abstract

• Vector polarized deuterons have been used in the nuclotron early.

• Tensor polarized run took place at the nuclotron now.

• The D+ cryogenic source POLARIS was used.

• Polarization of atomic beam was produced in the source by RF transitions between 2-6 and 3-5 states of hyperfine structure of deuterium atoms.

• The polarization of the beam was measured by some polarimeters:

- at the exit of the 10 MeV linac,

- inside the accelerator ring,

- after the beam extraction.

• The high tensor beam polarization value have been registered.

• It is measured as: + Pzz ~ 0.69 and - Pzz ~0.65.

• The source design and first results of polarization measurements are presented.

SOME SPIN TECHNOLOGY MILE STONES(atomic beam sources, accelerated beams)

1950–ies

Atomic physics. Rarefied gas dynamic. Free jets. Molecular and atomic beam formation.

1960-ies

Main physics ideas of ABS. Stern Gerlach separation. RF transition between atomic levels. First H+, D+ sources. I=1-3A. Low energy accelerated beams. Small scale university spin experiments. Dilution refrigerators, polarized solid targets.

1970-ies

SPIN technology is moved to high energies. Polarized ion source for the ANL accelerator ZGS, I= 4-6 A (DC), ~30A pulsed. Acceleration of the polarized protons and deuterons.

1972-1974

BINP, Siberia Snake ideas.

1974

1st SPIN Workshop at ANL. Polarized jet target proposal.

Later series: PST Workshops.

1981

DUBNA, ion source POLARIS, I = 200 A, polarized deuterons at the 10 GeV synchro- phasotron. Prof. Lapidus SPIN Workshop.

1984

SACLAY, 2.4 GeV polarized beam in the hard focusing machine SATURN 2; MIMAS, high beam intensity – 2*1011 p/pulse.

1985- 1989

BNL, Cs charge exchange H- ion source, polarized proton beam at AGS, 1st attack of high energy depolarization resonanzes.

PS INSTITUTE, ABS with ESR DC ionizer.

TROITSK, INR – ABS with short pulse plasma charge exchange ionizer.

INR, TRIUMPH, KEK H- -optical pumping sources, acceleration of polarized beams; spin experiments.

1990-ies

Parade of polarized beams at lepton machines: SLC, HERA, LEP, JLAB;

triumph of the e- «self-polarization» ideas.

GENERAL STRUCTURE OF THE NUCLOTRON

• ion source on 360 kV terminal, * 10 MeV/nucl. linear accelerator,• low energy polarimeters, * nuclotron ring up to 6 GeV/nucl.,• internal target polarimeter, * beam extraction,• high energy polarimeter, * experimental spectrometrs.

NUCLOTRON TUNNEL SEXTUPOL MAGNET

The cryogenic polarized source POLARIS have been developed for the Dubna 10 GeV synchrophasotron, to produce high energy polarized deuteron beam. It is used at the nuclotron now .

The source POLARIS consists of :

- a pulsed atomic beam stage with SC sextupole magnets for electron spin separation atoms,

- nuclear polarization RF cells,

- Penning plasma ionizer,

- spin precessor for vertical spin orientation.

POLARIZED DEUTERON D+ SOURCE POLARIS• The atomic stage has: dissociator, nozzle atomic beam source,

superconducting sextupole magnets for atom separation,• RF transition cells produce vector and tensor nuclear polarization,• The Penning ionizer has: high field SC solenoid, electron and ion optics for

ionization of the polarized atomic beam.• Spin precessor is used for vertical spin orientation of the beam. • Current of polarized beam is: 0.3-0.4 mA, the energy is: about 3 keV.• The vector and tensor polarizations are: Pz=+/-0.54; Pzz=+/-0.76.

SOURCE POLARIZATION UNITS Hyperfine states of D atoms•The source atomic beam stage

has two RF transition cells, to produce vector or tensor polarization of the atomic beam.

•Electron polarized atomic beam is flighed through the cell cavity, where hyperfine level transition takes place.

•Transitions between 1- 4 or 3-6 levels of produce two sign vector polarization of deuterium atoms.

•Transitions between 3-5 or 2-6 levels produce tensor polarization of atomic beam +/- Pzz.

•Chois of RF cell for each pulse is programable.

Hyperfine structure of hydrogen atoms

12

3

4

B/Bc

WW

0

F=1

F=0

0.5

1

-0.5

-1

m =1/2

-1/2

-1/2

+1/2

m = +1/2

m = -1/2

ij

j

RF transition Pz1 3 -12 4 +1

Pz =N - NN + N

= +- 1

B

N

N

RF transitions of D atoms

WW

0B/Bc

1

2

3

4

5

6

1

2

-1

-2

F= 32

F = 12

1 2 3

m = +1

0

-1

-1

0

+1

m = + 12

m = - 120

i

j

j

Gs

Gs

Magneticfield

Atomic beamdirection

8.5

44 3 6

1 4

B B

Pz~~ -0.57 Pz~~ +0.54

=8 MHz

=346.6 MHz

1 1

Magneticfield

Atomic beamdirection

B

3 5

2 6=381 MHz

=324.6 MHz

40

72

Atomic beam

Pzz -0.79~~ Pzz +0.76~~- +

B1 B1

Pz =N - NN + N + N

+-

230

N + N + NPzz = 1 - 3

0

N0

= ;

= +1 ... - 2

N < 1/3 , Pzz > 00

N = 1/3 , Pzz = 00

N > 1/3 , Pzz < 00

POLARIZED DEUTERON SOURCE POLARIS AT THE 10 MeV LINAC

POLARIMETRYThere are some polarimeters to measure polarizations of the high energy beam:

- polarimeter behaind a 10 MeV linac is monitoring beam polarization of the source,

- internal target polarimeter is measure polarization during acceleration,

- polarimeter with polyethylene target can measure left-right asymmetry of the extern. beam,

- polarimeter using deuteron inclusive breakup reaction is measure the tensor polarization.

HIGH ENERGY VECTOR POLARIMETER

Two-arm scintillation counter polarimeter with thin polyethylene target, based on the measurement of the asymmetry in the quasielastic pp-scattering.

HIGH ENERGY TENSOR POLARIMETER

A tensor polarimeter is based on the yield difference of stripping polarized and unpolarized proton at 00 in the deuteron breakup reaction.

LOW ENERGY VECTOR AND TENSOR POLARIMETER

3He, 4He target polarimeter to measure the vector and tensor

polarizations behind the10 MeV linac.

4He(d,d)4He, 3He(d,p)4He reactions are used.

INTERNAL TARGET STATION

deuteron d-p elastic scattaringpolarimeter

Polarization of the beam has been measured at 270 MeV :RF transitions: 2 - 6 3 - 5• Pzz : 0.671+/-0.046 -0.482+/-0.045• Pz : 0.246+/-0.033 0.251+/-0.026

VECTOR POLARIZED RUN AT THE NUCLOTRON RF TRANSITION: -Pz (1-4) +Pz (3-6)

•Beam polarization behind the linac:

- 0.56+/-0.07 ~85% 0.62+/-0.07 ~94%

• Internal target measurements:

at 3.5 GeV/c -0.58+/-0.04 0.59+/-0.04

at 5.0 GeV/c -0.56+/-0.03 0.60+/-0.03

• Polarization of the extracted beam:

at 3.5 GeV/c -0.54+/-0.02 0.56+/-0.02

at 5.0 GeV/c -0.62+/-0.02 0.60+/-0.02

•The vector polarization of the deuteron beam is retained during an acceleration and conformed by all polarimeters.

•As expected, the intensity of the polarized deuteron beam in one turn injection mode is observed as 1.3*108 d/pulse.

•The charge exchange multyturn injection is required.

TENSOR POLARIZED RUN AT THE NUCLOTRON

• The run has done, using D+ source POLARIS.

• The beam polarizations have measured:

- behind the 10 MeV linac by low energy polarimeter with 3He target,

- internal target polarimeter,

- external beam spectrometer.

• Beam polarization measurements are: + Pzz (2-6) - Pzz (3-5)

- behind the linac 0.690+/-0.131 - 0.669+/-0.161

- inside the ring at 270 MeV 0.671+/-0.046 -0.482+/-0.045

- after beam extraction at 3.4 GeV/c 0.27 +/- 0.14 -0.52 +/ -0.14

MULTYTURN INJECTIONBeam intensity depend on a source current and injection time.The nuclotron has a short one-turn injection (only 8s), factor 50 less then synchrophasotron.To increase the intensity of polarized deuteron beam the multyturn injection of the beam (20-30 turns) is required.

D- CHARGE EXCHANGE INJECTION

D- INJECTION BEAM ACCELERATION

Before the D- beam injection in to the ring, a trajectory bump is produced by elements of an accelerator lattice. The injected D- beam is banded by the lattice, passed through a foil target and stripped in to the positive D+ beam. Injected D- ions and circulating D+ beam can pass both through the foil target at the same time.