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Data processing in the Activation technique experiment
. Making stacked or sandwiched in the repeated order of Al-Cu-Mo.
• Irradiation of the samples
• Using HPGe-detector system, data were taken for sample foils and standard sources.
Calculation of Efficiency
At first, we need to calculate the efficiency of the standard sources.
Formula :
%100)(exp
/
%100)(exp
%100)(
0
0
ItA
meCountingTiNetArea
ItA
CPS
IA
DPSEfficiency
t
• Where, • Net area means the area under a photo peak.• A0 ; Initial activity of the standard sources .
Usually, it is written on the source. : Disintegration constant = 0.693 / T1/2
• T1/2 : is the half-life of the source
• I : intensity per decay of the gamma peak energy.
• t : Decay time ( Data taken date- source production date)
• However, the tables of measured efficiencies at different distances are given below
Table for efficiency measurement
Name of sources
Initial activity(Ci) A0
Half-Life(T1/2 )
Gamma ray energyE ( KeV)
Intensity per decay(I) %
Counting time(sec)
Counts of peak area ( Net area)
CPS relative error(%)
Efficiency relative error (%)
57 Co 9.938 271.79days
122.06065 85.33 600 12949140 21.58160.233
0.0474
136.47350 10.85 171374 2.8550.1233
0.0493
137 Cs 10.49 30.07years
661.657 85.1 600 20749168 34.58160.28
0.01100.0001
54Mn 10.13 312.1days
834.841 99.976 600 386474 6.440.1233
0.00920.0002
60C0 9.420 5.271years
1173.228 99.89 600 8045116 13.40830.1933
0.00510.0001
1332.490 99.98 6953108 11.58830.18
0.00440.0001
Measured Efficiencies at different source to detector distances
0 200 400 600 800 1000 1200 1400
0.05
0.10
0.15
0.20
0.25
0.30
Data: Data50_BModel: ExpDec1Equation: y = A1*exp(-x/t1) + y0Weighting: y No weighting Chi^2/DoF = 7.7084E-7R^2 = 0.9999 y0 0.04761 ±0.00077A1 0.2685 ±0.00109t1 341.72236 ±3.91968
Efficiency at 5 cms ExpDec1 fit of Data50_B
Effi
cien
cy (
%)
Gamma ray energy (keV)
0 200 400 600 800 1000 1200 14000.00
0.05
0.10
0.15
0.20
0.25
Data: Data13_BModel: ExpDec1Equation: y = A1*exp(-x/t1) + y0Weighting: y No weighting Chi^2/DoF = 0.00123R^2 = 0.82248 y0 0.03372 ±0.0318A1 0.25202 ±0.05705t1 342.23613 ±160.83041
Efficiency at 10 cms ExpDec1 fit of Data13_B
Effi
cien
cy (
%)
Gamma ray energy (keV)
0 200 400 600 800 1000 1200 14000.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
0.20
Data: Data53_BModel: ExpDec1Equation: y = A1*exp(-x/t1) + y0Weighting: y No weighting Chi^2/DoF = 5.1801E-7R^2 = 0.9999 y0 0.01515 ±0.00061A1 0.21839 ±0.00091t1 331.47646 ±3.7908
Efficiency at 20 cms ExpDec1 fit of Data53_B
Effi
cien
cy (
%)
Gamma ray energy (keV)
0 200 400 600 800 1000 1200 14000.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
Data: Data17_BModel: ExpDec1Equation: y = A1*exp(-x/t1) + y0Weighting: y No weighting Chi^2/DoF = 6.312E-6R^2 = 0.99881 y0 0.00891 ±0.00265A1 0.18048 ±0.00593t1 302.88643 ±31.26558
Efficiency at 30 cms ExpDec1 fit of Data17_B
Effi
cien
cy (
%)
Gamma ray energy (keV)
0 200 400 600 800 1000 1200 14000.00
0.01
0.02
0.03
0.04
0.05
Data: Data20_BModel: ExpDec1Equation: y = A1*exp(-x/t1) + y0Weighting: y No weighting Chi^2/DoF = 3.078E-6R^2 = 0.99592 y0 0.00344 ±0.00195A1 0.06719 ±0.00368t1 319.17585 ±59.57646
Efficiency at 50 cms ExpDec1 fit of Data20_B
Effi
cien
cy (
%)
Gamma ray energy (keV)
0 200 400 600 800 1000 1200 14000.000
0.005
0.010
0.015
0.020
0.025
0.030
0.035
Data: Data22_BModel: ExpDec1Equation: y = A1*exp(-x/t1) + y0Weighting: y No weighting Chi^2/DoF = 2.3442E-6R^2 = 0.98448 y0 0.00308 ±0.00113A1 0.04096 ±0.00209t1 289.36491 ±33.68459
Efficiency at 60 cms ExpDec1 fit of Data22_B
Effi
cien
cy (
%)
Gamma ray energy (keV)
Measurement of Beam/ Proton flux
P=35MeV
Al Cu(0.1mm) Mo(0.1mm)Al(0.1mm)Cu(0.1mm) Mo(0.1mm)Al(0.1mm)Cu(0.1mm)Mo(0.1mm)
29.8 25.0 20.0
Group A
P=35MeV
Al Cu(0.1mm) Mo(0.1mm)Al(0.1mm)Cu(0.1mm) Mo(0.1mm)Al(1.2mm) Mo(0.1mm)
25.2 17.6 13.4
Al(1.2mm)
Group B
Al(0.1mm)Cu(0.1mm)
7.9
Mo(0.1mm)
Al(0.1mm)Cu(0.1mm)
• For measuring beam flux, we used the Cu samples numbered 1, 4 & 7 from group A considering incident beam beam energies at 30 MeV, 25.2 MeV & 20.2 MeV respectively.
• The beam energy degradation was calculated using computer program
SRIM-2003.
Formula for Flux calculation
)exp1(
exp
irr
d
tIN
tCPS
• where,• CPS: Net area under a photo peak / counting time : Disintegration constant = 0.693 / T1/2
• T1/2 : is the half-life of the source• I : Gamma ray intensity
: Efficiency of the detector : Known cross section value• Tirr : irradiation time.• td : Decay time [( Start of counting time-end of irradiation time) +( 0.5*Counting time)]• N: Total number of target nuclide
= W F NA / Atomic weight of natural Copper• W= Weight of the samples• F = Isotopic abundance• NA= Avogadro’s number
Decay data of the produced radionuclides
Produced Nuclei Half-life Decay mode (%) Gamma ray EnergyE (keV)
IntensityI (%)
Contributing reactions Threshold Energy(MeV)
96g Tc 4.28 d EC (100) 778.224812.58849.921126.961200.2
99.7682.098.015.20.37
96Mo(p, n)97Mo(p,2n)98Mo(p,3n)96mTc decay
-3.79-10.69-19.42
95m Tc 61.0 d 204.117582.082835.149
63.2529.9626.63
95Mo(p, n)96Mo(p, 2n)97Mo(p, 3n)98Mo(p, 4n)
-2.47-11.74-18.44-27.09
95 Tc 20.0 h EC (100) 765.7941073.713
93.823.74
95Mo(p, n)96Mo(p, 2n)97Mo(p, 3n)98Mo(p, 4n)
-2.47-11.74-18.44-27.09
94 Tc 293 m EC (100) 702.626849.92871.082
99.695.7100
94Mo(p, n)95Mo(p, 2n)96Mo(p, 3n)97Mo(p, 4n)
-5.03-12.53-21.56-28.38
62 Zn 9.186 h EC++ (100) 548.35596.7
15.225.7
63Cu(p, 2n)65Cu(p, 4n)
-13.3-31.08
65 Zn 244.26 d EC++ (100) 1115.5 50.6 65Cu(p, n) -2.17
Value of proton flux
No of sample Flux for gamma energy (KeV) Source to detector distance
(cm)548.38 596.7
1 5.48108 5.37108 50
4 4.50108 4.34108 10
7 2.11108 2.05108 10
Calculation of Cross-section
• Cross-sections were calculated using the well known activation formula.
• Where, the symbols have their usual meanings.
)exp1(
exp
irr
d
tIN
tCPS
The obtained Cross-sectional values are as follows:
Produced Nuclide Value of cross-sections at different incident energy
30.3 MeV 26.3 MeV 24.8 MeV 17.9 MeV 13.5 MeV 8.43MeV
96g Tc 184 mb 167 mb 158 mb
96 Nb 3.73 mb 3.1 mb 2.6 mb
95m Tc 55.4 mb 50.5 mb 67.5 mb 50 mb 40.9 mb
95 gTc 107 mb 126 mb 189 mb
94g Tc 77.1 mb 85.3 mb 73.3 mb
Conclusions
• We tried to our best to report a reliable data set of the investigated radio nuclides.
• We do believe that we have done our job successfully.
Acknowledgment
• The author would like to give special thanks to the staffs of the Cyclotron Laboratories (KIRAM, Seoul) for their cordial help in performing the irradiations of the samples.
• This research received financial support from the MOST (Project Number M2-0409-00-0001
References:
1. Ziegler, J.F., Biersack, J.P., Littmark, U., SRIM 2003 code, Version 96.xx. The stopping and range of
ions in solids. Pergamon, New York.
2. E. Browne, R.B. Firestone, Table of Radioactive Isotopes, in: V.S. Shirley (ed.), Wiley, New York, 1986.
3. Reaction Q-values and thresholds, Los Alamos National Laboratory, T-2 Nuclear Information Service. Available from< http://t2.lanl.gov/data/qtool.html>
4. Monitor cross-section data Available at < http://www-nds.iaea.org/medical/cup62zn.html>
5. Takacs, S., Tarkanyi, F., Sonck, M., Hermanne, A., 2002. Investigation of the nat Mo(p,xn)96mgTc nuclear reaction to
monitor proton beams: new measurements and consequences on the earlier reported data. Nucl. Instrum. Method Phy. Res. B 198, 183-196.
6. Uddin, M.S., Hagiwara, M., Tarkanyi, F., Ditroi, F., Baba, M., 2004. Experimental studies on the proton-induced activation reactions of molybdenum in the energy range 22-67 MeV. Applied Radiation and Isotopes 60 (2004) 911-920.
7. Bonardi, M., Birattari, C., Groppi, F., Sabbioni, E., 2002. Thin-target excitation functions, cross-sections and optimized thick-target yields for natMo(p, xn)94g,95m,95g,96(m+g) Tc nuclear reactions induced by protons from threshold up to 44 MeV. No Carrier Added radiochemical separation and quality control. Applied Radiation and Isotopes 57 (2002) 617-635.
