Upload
shiro
View
46
Download
9
Embed Size (px)
DESCRIPTION
σ γ / k 0 measurements at Budapest PGAA facility. Zsolt R évay , László Szentmiklósi Institute of Isotopes Budapest. Practice of PGAA in Budapest. k 0 method Relative standardization Inelastic neutron scattering ( n,n’ γ ) background Using Hypermet - PowerPoint PPT Presentation
Citation preview
σγ / k0 measurements at Budapest PGAA facility
Zsolt Révay, László Szentmiklósi
Institute of Isotopes
Budapest
Practice of PGAA in Budapest
• k0 method
– Relative standardization
• Inelastic neutron scattering (n,n’γ) background– Using Hypermet
• Handling asymmetric peaks and overlaps
– Non-linearity– Efficiency
Why k0 method?
• Most accurate source of needed data
• k0 philosophy guarantees the highest reliability in measurements
• k0 idea can be better approximated in a beam
• Should be improved
Advantages of measurements in (cold) neutron beam
• No epithermal neutrons
• No non-1/v behavior (in cold beam)
• Lambert-Beer type self-shielding (low-divergence beam instead of isotropic neutron field)
• 20 MW
• water cooled
• water moderated
• thermal flux
1014 cm-2 s-1
Research Reactor
Neutron guides
• Ni or supermirror guides
• relatively small losses
• low background
Cold neutron
source at Budapest
400 cm3 20 K liquid H2
Budapest PGAA facilityC o n c re te
L e a d
A l tu b e
Va c u u m f it t in gL i-p o ly m e r
B G O C o m p to n su p p re s so r
• 10 MW• LH cold source• curved guide• Compton-
suppressed HPGe
• chopper
Budapest PGAA and NIPS facilities
PGAA facility
Compton suppression
2000 4000 6000 8000 10000 12000 14000 160001
10
100
1k
10k
100k
1M
Co
un
ts/C
ha
nn
el
Channel number
2000 4000 6000 8000 10000
1
10
100
1k
10k
100k
1M
E (keV)
1992 upgraded reactor starts1995 first PGAA measurement on the thermal beam1997–1998 establishment of PGAA data library1999–2000 applications2001 new cold beam2002 –2004 Handbook and Atlas
Main results in methodology• Data library transportable to other labs
• evaluation software
• complete analysis– analytical precision for the important
elements relative uncertainty: 1–2%
• application of chopped beam
Hypermet-PC
Hypermet-PC
• Asymmetric peak shape
• Non-linearity
• Efficiency fit
• Partial peak shape calibration
Efficiency
• One absolute source
• Lines from relative sources are normalized to it
• 200-300 data points
• 0.2% uncertainty at mid energy range
• 2% uncertainty at high energy range
Semiempirical efficiency function
102
103
104
10-6
10-5
10-4
10-3
Eff
icie
ncy
Energy (keV)
dead layer Al window total efficiency full-energy eff. photo single Compton multiple Compton pair
e-3 e-2 e-1 e0 e1 e2
Resid
uals
-3
0
3
Energy (MeV)
0.1 1 10
Efficien
cy
10-5
10-4
10-3
Ba-133Eu-152Bi-207Na-24N-15Poly8
Measured efficiency
Incorrect linear interpolation of the efficiency
0.02
0.025
0.03
0.035
0.04
0.045
0.05
100 1000 10000
energy (keV)
effi
cien
cy*E
^0.
73
1997-1999
2004
linear
The “elbow” of the efficiency
0.042
0.042435
0.04287
0.043305
0.04374
0.044175
0.04461
100 1000 10000
energy (keV)
effi
cien
cy*E
^0.
73
Prompt k0 project
Measurements of elements1 H
O1 D
O
2 He
3 Li
CO3,C-F
4 Be* O
5 B
C, H-O
6 C**
H
7 N
C-D-O,NO3
8 O
H, Be
9 F
C
10 Ne
11 Na* CO3 ,C-H-O
12 Mg*
13 Al** O
14 Si* O
N
15 P* O
16 S**
17 Cl
C,C-H
18 Ar*
19 K
HCO3
20 Ca* O
CO3
21 ScO
22 Ti** O
23 VO
24 Cr* O-H
25 Mn* O
26 Fe**
27 Co*
28 Ni**
29 Cu* O
30 Zn* O
31 Ga**
32 Ge* O
33 AsO
34 Se* O-H
35 Br*
C-H
36 Kr*
37 RbO
CO3
38 Sr
CO3
39 YO
40 ZrO
41 NbO
42 Mo**
43 (Tc) 44 Ru**
45 Rh*
C-H
46 Pd*
47 Ag**
48 Cd**
49 In*
50 Sn**
51 SbO
52 Te**
53 I*
C-H
54 Xe
F
55 CsO
56 Ba
OH,CO3
57 LaO
72 Hf* O
73 Ta* O
74 WO
75 Re*
76 Os* O
C-H
77 Ir* O
78 Pt*
79 Au*
80 Hg** O
81 Tl*
82 Pb**
83 Bi**
84 (Po) 85 (At) 86 (Rn)
87 (Fr) 88 (Ra) 89 (Ac)
58 CeO
C-H-O
59 PrO
60 NdO
61 (Pm) 62 SmO
63 EuO
64 GdO
65 TbO
66 Dy*
67 HoO
68 ErO
69 TmO
70 YbO
71 LuO
90 Th
NO3
91 (Pa) 92 UO
C-H-O
Standardization1 Halap
1 D
H
2 He
3 Li
C,N
4 Be
N, O
5 BH
6 CH
N
7 NH Cl
8 OH
9 F
K,C,Ca
10 Ne
11 NaH Cl
S B
12 MgH Cl
S,Fe*B
13 AlH Cl
S,Fe*B
14 SiN O
Fe*
15 PH
Na
16 SH
Na, Al
17 Cl3H
B
18 Ar
absz: Cl
19 KH Cl
B
20 CaCl
Fe*
21 ScH
S,Ti B
22 TiCl
23 VH
B
24 CrH Cl
25 MnH Cl
B
26 Fe2Cl
27 CoH Cl
B
28 NiH Cl
B
29 CuH Cl
30 ZnCl
B
31 GaH
N B
32 Ge
Co B
33 AsH
Na B
34 SeH
B
35 BrH Cl
B
36 Kr
37 RbCl
B
38 SrCl
B
39 YCl
B
40 ZrCl
N
41 NbCl
42 MoCl
43 (Tc) 44 RuH Cl
45 RhH Cl
46 PdCl
47 AgH Cl
48 CdH Cl
49 In
Sb B
50 SnH Cl
51 Sb
S
52 TeH Cl
53 IH Cl
54 Xe
F
55 CsCl
56 BaH Cl
57 LaCl
72 HfH Cl
73 TaH
Ti,H
74 WH
Na
75 ReCl
76 OsH
77 IrCl
78 PtCl
79 AuH Cl
80 HgCl
81 Tl
S
82 PbCl
N
83 BiCl
84 (Po) 85 (At) 86 (Rn)
87 (Fr) 88 (Ra) 89 (Ac)
58 Ce
H
C
59 Pr
H
S
60 Nd
H
S
61(Pm) 62 Sm
H
S
63 Eu
H
S B
64 Gd
H
S
65 Tb
H
S
66 Dy
H
S
67 Ho
H
S
68 Er
H
Cl
69 Tm
H
S
70 Yb
H
71 Lu
H
S
90 ThHN B
91 Pa 92 UHC B
PGAA libraryZ El A MW # E dE d% RI Area cps/g1 H 1 1.01 1 2223.259 0.019 0.3326 0.2 100.00 100.00 64.1831 H 2 1.01 2 6250.204 0.098 0.000492 5.0 0.15 5.00 0.02863 Li 6 6.94 5 477.586 0.050 0.001399 5.9 3.52 10.14 0.12183 Li 7 6.94 2 980.559 0.046 0.004365 5.1 10.97 18.74 0.22513 Li 7 6.94 3 1051.817 0.048 0.004364 5.1 10.97 17.83 0.21413 Li 7 6.94 1 2032.310 0.070 0.0398 5.0 100.00 100.00 1.20073 Li 6 6.94 6 6769.633 0.263 0.001354 6.5 3.40 0.84 0.01013 Li 6 6.94 4 7246.800 0.275 0.002106 8.4 5.29 1.17 0.0144 Be 9 9.01 4 853.631 0.011 0.00165 8.9 26.69 100.00 0.07234 Be 9 9.01 3 2590.014 0.025 0.00188 8.9 30.41 49.08 0.03554 Be 9 9.01 2 3367.484 0.035 0.002924 8.9 47.30 58.96 0.04274 Be 9 9.01 5 3443.421 0.036 0.000993 8.9 16.06 19.54 0.01414 Be 9 9.01 6 5956.602 0.092 0.000146 9.1 2.36 1.41 0.0014 Be 9 9.01 1 6809.579 0.099 0.006181 9.0 100.00 48.52 0.03515 B 10 10.81 1 477.600 5.000 712.5 0.3 100.00 100.00 398066 C 12 12.01 2 1261.708 0.057 0.00123 2.7 45.58 100.00 0.03066 C 12 12.01 3 3684.016 0.069 0.001175 3.5 43.53 38.02 0.01166 C 12 12.01 1 4945.302 0.066 0.002699 2.9 100.00 60.55 0.01867 N 14 14.01 22 583.567 0.031 0.000429 3.3 1.81 6.93 0.01597 N 14 14.01 12 1678.244 0.029 0.006254 1.5 26.34 47.15 0.10857 N 14 14.01 18 1681.174 0.043 0.001296 2.7 5.46 9.76 0.02257 N 14 14.01 21 1853.944 0.052 0.000474 4.5 2.00 3.31 0.00767 N 14 14.01 5 1884.853 0.031 0.0145 1.3 61.07 100.00 0.23017 N 14 14.01 24 1988.532 0.077 0.000294 5.8 1.24 1.94 0.00457 N 14 14.01 15 1999.693 0.032 0.003208 1.7 13.51 21.12 0.04867 N 14 14.01 13 2520.446 0.039 0.004246 1.8 17.88 22.98 0.0529
Verification1 Hkompoldatok
1 D
H
2 He
3 Li 4 Be 5 BH,üveg
GEO
6 Ckarbo-nátok
7 Nkomp
8 Ooxidok
9 FCa
10 Ne
11 Nakomp
üveg
12 Mgüveg
13 Alcem,kat,GEO
14 Siüveg,kat,GEO
15 PH
Na
16 SkompcemGEO
17 Clkomp
18 Ar
19 KSRM
20 CaSRM,cem
21 Sc 22 TiCl
GEO
23 Vkat
24 CrSRM,
kat
25 MnSRM
GEO
26 FeSRM,GEO
27 Cooldat
28 Nikat,fémüveg
29 CuAg-Cu
30 Zn 31 Ga 32 Ge 33 As 34 Se 35 Br 36 Kr
37 RbB38 Sr 39 Y 40 Zr
fémüveg41 Nbkat
42 Mokat
43 (Tc) 44 Ru 45 Rh 46 Pdfémüveg
47 AgAg-Cu
48 CdSRM
GEO
49 In 50 SnSn-Cd
51 Sb 52 Te 53 I 54 Xe
55 Cs 56 Ba 57 La 72 Hf 73 Ta 74 W 75 Re 76 Os 77 Ir 78 Ptkat
79 Aukomp
80 Hg 81 Tl 82 PbPb-Cd
83 Bi 84 (Po) 85 (At) 86 (Rn)
87 (Fr) 88 (Ra) 89 (Ac)
58 Ce 59 Pr 60 Nd 61(Pm) 62 Sm 63 Eu 64 Gd
üveg,GEO
65 Tb 66 Dy 67 Ho 68 Er 69 Tm 70 Yb 71 Lu
90 Th 91 Pa 92 U
Prompt k0 factors
• relative to Cl 1951 keV line• relative to H 2223 keV line
• σγ = θ γ σ
x
c
cc
xx
x
c
c
xc n
n
A
A
M
Mk
/
/
,
,,0
Decay gammas in PGAA spectra
• can be used for analysis, too
• k0-s can be measured
• depending on half-life, saturation correction needed
Prompt saturation factor
• activation and decay at the same time
11
teB
t
Activation
0 1 2 3 4 5 *t
rel.
nu
mb
er
of
cou
nts
promptdecayshifted prompt
Advantages of the in-beam measurement compared to
cyclic activation• uncertainties from
– half-life– timing
do not accumulate
k0-s for short lived nuclidesFinal
nuclide
Energy
(keV)Half-life Theoretical k0
8k0
De Corte et al1
k0
Roth et al2
k0
present work
20F 1633.6 11.03 0.06 s (1.060.05) 10–3 (1.010.007) 10–3 (1.060.04) 10–3
24mNa 472.28 20.2 0.1 ms (4.820.05) 10–2 (3.630.02) 10–2 (4.340.03) 10–2
28Al 1778.99 2.2414 0.0001 m (1.79 0.02) 10–2 (1.750.01) 10–2 (1.800.02) 10–2
38mCl 671.33 0.715 0.003 s (6.7 1.4) 10–3 (7.950.14) 10–4 (7.60.8) 10–4
46Sc 142.53 18.7 0.05 s 0.282 0.033 0.227.002 0.226 0.002
51Ti 320.08 5.76 0.01 m (3.77 0.07) 10–4 (3.740.04) 10–4 (3.660.11) 10–4
52V 1434.08 3.75 0.01 m 0.2 0.005 0.196 0.002 0.197 0.004
56Mn 846.81 2.5785 0.0006 h 0.5 0.008 0.496 0.030 0.502 0.006
60mCo 1332.5 10.47 0.006 m 3.3 10–3 (3.200.09) 10–3
66Cu 1039.35 5.088 0.011 m (1.60.4) 10–3 (1.860.009) 10–3 (1.970.04) 10–3
77mGe 215.48 52.9 0.6 s 2.69 10–5 (2.68 0.13) 10–5
77mSe 161.92 17.45 0.1 s 0.0290.001 (2.570.001) 10–2 (2.240.04) 10–2
Chopped-beam PGAA
TOF
Beam chopper
• Variable opening: 0.2 – 50%
• variable frequency: 3 – 100 Hz
• Beam periodically shielded by Gd, 6Li
Time of flight
n
gamma radiation
detectorchopper
Rotating and standing slits
Cold and thermal neutron spectra
Wavelength spectra of thermal and cold beams
1.E-05
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
0 5 10 15 20
wavelength (AA)
TN1
CN1
Candidates for in-beam measurement
< 1 s: Na,
< 1 min: F, Sc, Ge, Pd, Ag, In, Er, Hf, W,
< 10 min Mg, Al, V, Cr, Se, Br, Rh, Dy, Ir,
< 1 h: Ga, Rb, Sn, I, Pr, Nd, Ta, Re,
<1 day: Mn, Cu, Sr, Cs, Ba, Eu, Lu,
longer: As, Ru, La, Ce, Tb, Ho, Yb, Au,
Isotopes with high Er
Q0 Er Isot sigma1.12 2280 37S 0.151.14 1040 64Cu 2.171.908 2560 65Zn 0.762.38 3540 75mGe 0.171.57 3540 75Ge 0.345.93 4300 90mY 0.0015.05 6260 95Zr 0.04991.8 2950 131I 6.21.2 1540 143Ce 0.95
First prototype of chopper
Budapest PGAA facility (L. Sz.)
Simultaneous PGAA and NAA measurement with a chopper
• Beam open
prompt gamma rays
decay gamma rays
Usual PGAA spectrum
• Beam closed
only decay gamma rays
cyclic NAA spectrum
21
14
Mn
18
48
18
11
Mn
17
79
Al
15
13
13
64
13
26
11
31
10
268
47
Mn
82
3
69
0
51
1 A
nn
ih.
59
0
90
Tc-
99
53
8
12
01
172 Tc-100 p
1E-5
1E-4
1E-3
1E-2
1E-1
1E+0
1E+1
1E+2
0 500 1000 1500 2000 2500
E [keV]
Co
un
t ra
te [c
ps
]
Tc-100 decay
Tc-99 capture
Prompt and decay spectrum of Tc-99
Name Reactor Beam Vacuum Chopper Phase Backgound
(cps)
Room background off – – – – 0.63
Beam-off background on off – – – 1.5
Beam-on background
(in vacuum)
on on yes – – 4.0
Beam background in air on on no – – 5.6
Chopper background in
prompt phase
on on no on prompt 5.3
Chopper background in
decay phase
on on no on decay 4.6
Background
prompt spectrum decay spectrum gainEl E (keV)
rate S/N rate S/N
F 1633 1.63(2) 1300 1.63(6) 7000 5
Al 1779 2.62(1) 2000 2.61(1) 200,000 100
Sc 143 28(1) 200 29(1) 40,000 20
147 46.8(7) 400
V 125 20.0(2) 270
1434 9.3(1) 1200 8.8(4) 41,000 34
Cu 159 29.6(2) 200
1039 0.58(2) 90 0.55(2) 900 10
Ag 198 82(1) 62
658 7.16(15) 20 7.3(3) 1900 95
In 163 157(3) 53 146(6) 3700 70
Er 185 32(1) 400
208 14.6(8) 180 15.4(6) 11,000 60
Mea-sure-ments
0.0001
0.001
0.01
0.1
1
10
100
0 1000 2000 3000 4000 5000 6000E (keV)
Inte
nsity
(cps
)
prompt
decay
background
Spectra
0.001
0.01
0.1
1
10
600 620 640 660 680 700
E (keV)
Inte
nsi
ty (
cps)
promptdecay
108Ag 110Ag
Prompt and decay spectrum of Ag
ResultsElement Half-life Energy (keV) decay
line
(barn)
prompt line
(barn)
F 11.16 s 1633 0.0093(3) –
Al 2.24 m 1779 0.233(4) <0.005
Sc 18.75 s 143 4.88(10) <0.13
V 3.75 m 1434 5.20(10) <0.3
Cu 5.12 m 1039 0.0600(12) <0.0023
Ag 24.6 s 658 1.93(4) <0.08
In 2.18 s 163 15.8(8) <1.1
Er 2.27 s 208 2.15(9) <0.18
Second prototype chopper
In-beam saturation factor (B) (LSz)
11
mt
m
eB
t
Type I nuclides, on-line counting
3 3 3233 1 2
3 2
( ) 1 1t t ttm gdR t N E F e e e e
Count rate of #3 from Bateman-Rubinson equations:
3 23
2 22 3
23 3 2 2 3
1 111 1
m mm
t tmt
gm m
e eeB F
t t
Type IV nuclides Type IV/B
nuclides
Type IV/A nuclides
Results 1/3 (LSz)
Sample Nuclide Energy, keV
k0,Au (Rel. unc %)
Literature Z-score
PTFE cylinder 20F 1633 0.00102 (2.2%) 9.98E-4 (1.2%) 1.01E-3 (0.7%)
0.87 0.44
Na2S2O3.5H2O 24Na 1369 0.047646 (1.8%) 4.68E-02 (0.6%) 0.94 2754 0.047591 (2.2%) 4.62E-02 (0.8%) 1.26 Al(OH)3
28Al 1779 0.017946 (1.1%) 1.75E-02 (0.8%) 1.80 MnCl2.4H2O 38mCl 671 0.000791 (5.1%) 7.95E-04 (1.7%) -0.09 38Cl 1642 0.00202 (6.1%) 1.97E-03 (1.4%) 0.43 2167 0.00280 (4.8%) 2.66E-03 (1.3%) 1.01 56Mn 847 0.499 (1.0%) 4.96E-01 (0.6%) 0.54 1811 0.1351 (1.1%) 1.35E-01 (0.4%) 0.09 2113 0.0728 (1.8%) 7.17E-02 (0.2%) 0.83 Sc2(SO4)3
46Sc 143 0.225 (2.1%) 0.2270 (0.7%) -0.42
Literature data taken from:F. De Corte, A. Simonits, Atomic Data and Nuclear Data Tables 85 (2003) 47.S. Roth, F. Grass, F. De Corte, L. Moens, K. Buchtela, J. Radioanal. Nucl. Chem. 169 (1993) 159.S. Van Lierde, F. De Corte, D. Bossus, R. Van Sluijs, S. Pommé, Nucl. Instr. Meth. A 422 (1999) 874.
Results 2/3 (LSz)
Sample Nuclide Energy, keV
k0,Au (Rel. unc %)
Literature Z-score
KBr+H2O 80Br 616 0.00675 (1.5%) 6.92E-03 (0.3%) -1.71
666 0.00122 (2.3%) 1.22E-03 (0.5%) -0.04
82Br 554 0.02315 (1.9%) 2.38E-02 (1.1%) -1.28 619 0.01387 (2.0%) 1.45E-02 (0.8%) -2.11 698 0.00917 (2.2%) 9.38E-03 (0.9%) -0.98 777 0.02756 (1.4%) 2.76E-02 (0.8%) -0.10 828 0.00753 (3.1%) 7.99E-03 (0.9%) -1.87 1044 0.00872 (2.7%) 9.14E-03 (0.7%) -1.71 1317 0.00828 (3.0%) 8.91E-03 (0.4%) -2.54 1475 0.00536 (3.5%) 5.42E-03 (0.5%) -0.33 KI+H2O 127I 443 0.0117 (0.9%) 1.12E-02 (1.7%) 2.12 527 0.0011 (2.0%) 1.07E-03 (1.4%) 1.40 HfOCl2.8H2O 179m1Hf 214 0.176 (1.6%) 0.1770 (0.2%) -0.36
Results 3/3 (LSz)
Sample Nuclide Energy, keV
k0,Au (Rel. unc %)
Literature Z-score
H2WO4 187W 134
0.0117 (1.6%) 1.13E-02 (0.7%) 2.04 478 0.0299 (1.4%) 2.97E-02 (1.0%) 0.34 552 0.00693 (1.4%) 6.91E-03 (0.5%) 0.21 618 0.00856 (1.4%) 8.65E-03 (0.7%) -0.64 625 0.00151 (2.2%) 1.48E-03 (–) – 686 0.0379 (1.6%) 3.71E-02 (0.5%) 1.21 773 0.00563 (1.4%) 5.61E-03 (0.7%) 0.19 RbNO3+H2O 86mRb 556 0.000999 (2.1%) 9.96E-04 (1.6%) 0.13 88Rb 898 0.00011 (4.8%) 1.01E-04 (1.5%) 2.32 1836 0.00017 (5.2%) 1.57E-04 (1.1%) 0.97 AgNO3+H2O 108Ag 434 0.00168 (4.8%) 1.59E-03 (2.0%) 1.07 619 0.00105 (6.7%) 9.33E-04 (0.8%) 1.72 633 0.00585 (1.6%) 6.01E-03 (0.8%) -1.50 110Ag 658 0.03627 (1.2%)=
1.881 b (1.2%) 1.93 b (2.1%)
1.06
Cross-section measurements for fissile material
• Uranium– 235U– 238U– Fission products
• Thorium – still going on
Conclusion
• In-beam activation can be used for σγ /k0 measurements– No epithermal activation– Short lived nuclides can be measured well– Simple self-shielding– No resonances in cold beam