JAEA-Conf 2011-002 - 日本原子力研究開発機構

More documents

Recommendations

Info

Fig.1. Experimental arrangement for the capture cross section measurement LINAC Condition JAEA-Conf 2011-002 Table 1. Details of the measurement conditions High Energy Low Energy measurement measurement Repetition rate 200 Hz 50 Hz Pulse width 100 nsec 100 nsec Average current 63.0 A 16.5 A Cd filter On off Table 2. Physical parameters of the samples used in the experiment Sample 151 Eu 153 Eu 10 B Chemical Form Oxide (Eu2O3) Oxide (Eu2O3) Metal powder Isotope Composition 151 Eu : 97.60% 153 Eu : 99.71% 10 B: 96.98% 153 Eu : 2.4% 151 Eu: 0.29% 11 B: 3.02% Weight (g) 0.115 0.114 3.60 Thickness (g/cm 2 ) 0.0288 0.0285 0.947 Number of atoms 3.86×10 20 3.87×10 20 5.55×10 22 Size of sample 2.0×2.0 cm 2 2.0×2.0 cm 2 2.2 cm in diam. 3. Data Processing and Analysis 3.1 Neutron Capture Cross Section The neutron capture cross sections for 151,153 Eu were obtained by the following relation: Y ( E ) s n cs ( En ) = fcs ( En ) ⋅ (1) φ 0( En ) ⋅ Ns xs where the subscript “S” means an objective nuclide of 151 Eu or 153 Eu. Ns and xs are the atomic density and sample thickness, cs(En) is the neutron capture cross section, Ys(En) is the energy dependent neutron capture yield, φ0(En) is the incident neutron flux on the sample and ƒcs(En) is the correction function. The correction for the neutron self-shielding and multiple scattering in each sample was made by the MCNP-4C (Monte-Carlo Code for Neutron and Photon Transport, version 4C) [2] with the nuclear data taken from JENDL-4.0 [3]. As for 153 Eu, the correction for the capture yields due to the isotopic impurity in the sample was also done by using the present results of 151 Eu. The methods to
derive the incident neutron flux and the neutron capture yield are briefly described in the following sections. 3.2 Incident Neutron Flux A 10 B sample was used to determine the incident neutron flux on the sample. The 10 B(n,γ) 7 Li reaction emits a single γ ray of 478 keV. It means that the detection efficiency for the reaction is independent of neutron energy. Then, the neutron flux is given by the following relation: C ( ) ( ) B E φ 0 E n n = (2) ε BYB ( En ) where the subscript “B” means 10 B. CB(En) is the counting rate at energy En, YB(En) is the energy dependent capture yield for the 10 B(n,γ) 7 Li reaction, εB is the detection efficiency for the 478-keV γ ray which was calculated with the EGS5 [4]. The neutron capture yield YB(En) was obtained by the Monte Carlo calculation with the MCNP-4C. The nuclear data used for the Monte-Carlo simulation were taken from JENDL-4.0. 3.3 Neutron Capture Yield The γ-ray detection efficiency of the pair of C6D6 liquid scintillators is small enough not to count two or more γ rays per capture event. Therefore, the efficiency for detecting capture events depends on decay modes of compound nucleus. By applying a weighting function, W(I), on the observed PH spectrum, the detector can be treated as a total energy detector having a γ-ray detection efficiency proportional to an incident γ-ray energy [5]. Since the sum of γ-ray energies emitted from a capture event is independent of decay modes, the efficiency for detecting capture events is also proportional to the excitation energy of capture state. The weighting function, W(I), was defined as follows: W( I ) R( I , Eγ ) = Eγ (3) I where R(I, Eγ) is the response function defined as the probability that a γ ray with an energy of Eγ emitted from the sample position into isotropic was detected in the I-th channel of the PH spectrum. The response functions for discrete γ-ray energies from 0.5 to 7.0 MeV were obtained by the calculation with the EGS5 and the experiments with standard γ-ray sources as shown in Fig. 2. The weighting function was determined by means of a least square fitting so as to minimize the following χ 2 : 2 JAEA-Conf 2011-002 2 2 χ = W ( I ) R( I , Ei ) − Ei E (4) i i I The weighting function for the pair of C6D6 liquid scintillators is shown in Fig. 3. The neutron capture yield was obtained as follows: S( I ) W ( I ) I Y = BE + En (5) where S(I) is the capture γ-ray PH spectrum, BE is the neutron binding energy of target nucleus, En is the incident neutron energy. The capture γ-ray PH spectrum, S(I), was obtained by subtracting the background(BG) from the foreground PH spectrum corresponding to each TOF region. The BG spectrum was estimated from the measurements with an empty case. 4. Results and Discussion (1) 151 Eu The preliminary neutron capture cross sections of 151 Eu were obtained in the neutron energy region from 0.03 eV to 100 keV as shown in Fig. 4. A number of experiments were reported for 151 Eu and they are also shown in the figure for comparison. The present results give good agreement with those experimental data, and hence we can conclude that the validity of the weighting function derived
Page 3:
JAEA-Conf 2011-002 Proceedings of t
Page 7:
JAEA-Conf 2011-002 31. Preliminary
Page 12 and 13:
6.2 Measurement of neutron-induced
Page 14 and 15:
This is a blank page.
Page 16 and 17:
JAEA-Conf 2011-002 Table 1 Comparis
Page 18 and 19:
JAEA-Conf 2011-002 (T1/2=8,900,000
Page 20 and 21:
JAEA-Conf 2011-002 Though words too
Page 22 and 23:
JENDL-3.3 showed better applicabili
Page 24 and 25:
ENDF. Thus this cross section store
Page 26 and 27:
Acknowledgement JAEA-Conf 2011-002
Page 28 and 29:
In the MALIBU program, isotope conc
Page 30 and 31:
some minor actinides. For major act
Page 32 and 33:
JAEA-Conf 2011-002 code MVP-BURN an
Page 34 and 35:
JAEA-Conf 2011-002 [3] Measurements
Page 36 and 37:
3.1 Experimental Set up JAEA-Conf 2
Page 38 and 39:
References JAEA-Conf 2011-002 [1] N
Page 40 and 41:
JAEA-Conf 2011-002 was large. The a
Page 42 and 43:
JAEA-Conf 2011-002 4. Results and D
Page 44 and 45:
Acknowledgments Present study inclu
Page 46 and 47:
Fig. 1 A conceptural picture of the
Page 48 and 49:
4. Theoretical studies Theoretical
Page 50 and 51:
JAEA-Conf 2011-002 Fig.9 Comparison
Page 52 and 53:
Ion source JAEA-Conf 2011-002 LE
Page 54 and 55:
JAEA-Conf 2011-002 3. Readiness
Page 56 and 57:
JAEA-Conf 2011-002
Page 58 and 59:
JAEA-Conf 2011-002 Figure 1. An exa
Page 60 and 61:
JAEA-Conf 2011-002 Figure 6. Compar
Page 62 and 63: JAEA-Conf 2011-002 calculation of d
Page 64 and 65: JAEA-Conf 2011-002 equilibrium emis
Page 66 and 67: JAEA-Conf 2011-002 Cowley et al. [1
Page 68 and 69: 4. Conclusions We have compared nuc
Page 70 and 71: of MeV region with highest cosmic-r
Page 72 and 73: JAEA-Conf 2011-002 events can be id
Page 74 and 75: JAEA-Conf 2011-002 models and its p
Page 76 and 77: JAEA-Conf 2011-002
Page 78 and 79: JAEA-Conf 2011-002
Page 80 and 81: JAEA-Conf 2011-002 xx
Page 82 and 83: JAEA-Conf 2011-002 1. The recent ac
Page 84 and 85: JAEA-Conf 2011-002 4. Conceptual de
Page 86 and 87: This is a blank page.
Page 88 and 89: The Institute's staff of about 280
Page 90 and 91: 3. Nuclear Theory Laboratory JAEA-C
Page 92 and 93: JAEA-Conf 2011-002 References [1] P
Page 94 and 95: JAEA-Conf 2011-002 reaction 6 Li +
Page 96 and 97: Using the approximated distribution
Page 98 and 99: This is a blank page.
Page 100 and 101: momentum of the constituents of P.
Page 102 and 103: dσ/dΩ (mb/sr) c.m. scattering ang
Page 104 and 105: JAEA-Conf 2011-002 [2] N. Austern,
Page 106 and 107: moderating fast neutrons emitted fr
Page 108 and 109: JAEA-Conf 2011-002 3. Results and d
Page 110 and 111: JAEA-Conf 2011-002 the detection de
Page 114 and 115: in this work was confirmed. (2) 153
Page 116 and 117: Neutron Capture Cross Section of 15
Page 118 and 119: ENDF resonance parameters are based
Page 120 and 121: sample changer. The measured flux s
Page 122: REFERENCES JAEA-Conf 2011-002 [1] W
Page 125 and 126: JAEA-Conf 2011-002 Fig. 4: The rela
Page 127: Fig. 10: The PHITS2 calculation geo
Page 130 and 131: for such a low energy region should
Page 132 and 133: MCNPX calculation was performed bas
Page 134 and 135: JAEA-Conf 2011-002 We measured dou
Page 136 and 137: 1mm-thick carbon target 22mm in dia
Page 138 and 139: JAEA-Conf 2011-002 Figure 2 shows e
Page 140 and 141: The double-differential (n,xp) and
Page 142 and 143: JAEA-Conf 2011-002 forward angles.
Page 144 and 145: Fig.3. Two-dimensional plot of PI v
Page 146 and 147: JAEA-Conf 2011-002 Fig. 7. Deuteron
Page 148 and 149: JAEA-Conf 2011-002 The new detector
Page 150 and 151: 4. Off line data analysis Double di
Page 152 and 153: eports of data of carbon-ion incide
Page 154 and 155: Count [-] 4 10 3 10 2 10 10 1 Charg
Page 156 and 157: Acknowledgement We are grateful to
Page 158 and 159: Beam Line BM1 Copper Target BM2 5×
Page 160 and 161: φ = φbm · ρtof · ρmulti (2) E
Page 162 and 163:
References [1] K. Ishibashi, H. Tak
Page 164 and 165:
JAEA-Conf 2011-002 hint at the orig
Page 166 and 167:
Neutron Dose Rate [Sv/hr/src neutro
Page 168 and 169:
JAEA-Conf 2011-002 radiation protec
Page 170 and 171:
Ztarget, Atarget are the numbers fo
Page 172 and 173:
We described our formalism for calc
Page 174 and 175:
2. Model
Page 176 and 177:
JAEA-Conf 2011-002
Page 178 and 179:
JAEA-Conf 2011-002
Page 180 and 181:
JAEA-Conf 2011-002 reactions. Figur
Page 182 and 183:
JAEA-Conf 2011-002 Fig. 3. The angu
Page 184 and 185:
Page 186 and 187:
JAEA-Conf 2011-002
Page 188 and 189:
JAEA-Conf 2011-002
Page 190 and 191:
JAEA-Conf 2011-002
Page 192 and 193:
analysis of integral experiments [6
Page 194 and 195:
A modified SRAC library was prepare
Page 196 and 197:
JAEA-Conf 2011-002 approximately 0.
Page 198 and 199:
JAEA-Conf 2011-002 constructing the
Page 200 and 201:
Fig.9 Spectrum of gamma-ray followi
Page 202 and 203:
Page 204 and 205:
JAEA-Conf 2011-002 in the same way
Page 206 and 207:
JAEA-Conf 2011-002 [7]. For example
Page 208 and 209:
Page 210 and 211:
JAEA-Conf 2011-002 For
Page 212 and 213:
JAEA-Conf 2011-002
Page 214 and 215:
JAEA-Conf 2011-002
Page 216 and 217:
JAEA-Conf 2011-002 (5.0-9.0MeV), a
Page 218 and 219:
components, the 0.56Wt% for hydroge
Page 220 and 221:
Page 222 and 223:
Sensitivities of curium isotope con
Page 224 and 225:
decreases of (n,g) reaction rates,
Page 226 and 227:
5. Conclusion JAEA-Conf 2011-002 Wi
Page 228 and 229:
2. Foundation of sensitivity analys
Page 230 and 231:
JAEA-Conf 2011-002 where f g and f
Page 232 and 233:
Fig.1 Sensitivity coefficient of th
Page 234 and 235:
An outline of core configurations o
Page 236 and 237:
0.010% 0.000% -0.010% -0.020% -0.03
Page 238 and 239:
To clarify what nuclides and reacti
Page 240 and 241:
Calculation was performed by the MV
Page 242 and 243:
among these libraries, and the diff
Page 244 and 245:
Page 246 and 247:
JAEA-Conf 2011-002
Page 248 and 249:
JAEA-Conf 2011-002
Page 250 and 251:
JAEA-Conf 2011-002
show all

JAEA-Conf 2011-002 - 日本原子力研究開発機構

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?