Prompt γ-rays from Neutron Inelastic

Prompt γ-rays from Neutron Inelastic Scattering at FaNGaS: Benchmark Spectrum Analysis T.H. Randriamalala, M. Rossbach Institute of Energy and Climate Research, Nuclear Waste Management and Reactor Safety, Forschungszentrum Jülich GmbH, Germany August 23-28, 2015 MTAA 14 Delft, The Netherlands

Outline Introduction & Motivation Experimental Setup Sample Properties Benchmark Studies Conclusion & Outlook T.H. Randriamalala August 28, 2015 MTAA 14 2

Introduction & Motivation Prompt γ-rays Neutron Activation Analysis (m n, E ther. ) (m n, E > E T ) (m n, E ) Requirement for the use of fast neutrons interrogation: Knowledge of the absolute intensities or/and the partial cross section of (prompt) γ-rays Knowledge of the total (n, n γ) cross section T.H. Randriamalala August 28, 2015 MTAA 14 3

Introduction & Motivation FaNGaS The Fast Neutron Gamma Spectrometry aims to investigate (n, n γ) reaction using the ssion neutrons at FRM II, Garching. Scope of presentation: Confrontation of the measured intensity and count rate of γ-rays with the existing data or with the calculation results from theoretical model. T.H. Randriamalala August 28, 2015 MTAA 14 4

The Facility 6 7 5 4 3 2 1 8 D 2 7 = 548 cm D 7 6 = 67 cm 1 Reactor core 4 Inner collimator 7 Irradiation position 2 Convertor plates (93% 235 U) 5 Outer collimator 8 Decay measurement 3 SR10 beam line 6 Shielded 50% HPGe position detector T.H. Randriamalala August 28, 2015 MTAA 14 5

FaNGaS Instrument 2 4 1 3 1 Outer 2 Sample holder 3 γ 4 Detector shielding 5 collimator collimator (PE 5 n B4 C Pb ) Iron frame support W H L 126 cm 126 cm 266 cm Weight 4 tonnes Movable instrument T.H. Randriamalala August 28, 2015 MTAA 14 6

Beam Characteristic Neutron Beam Spectrum (Very pure) foil activation technique: Sample irrad. time 10 h Decay meas. time 1-2 h 12 threshold and 5 (n, γ) reactions Spectrum unfolding using STAYSL PNNL 1 code: Parametrized prior ux 2 : φ(e) = α t E exp( E/kT ) + α i E (1+c) exp( d/ E) + α f exp( E/a) sinh( be) 1 F.G. Perey, ORNL-TM-6062(1997). 2 H. Breitkreuz et al. NIM A 593 (2008) 466. T.H. Randriamalala August 28, 2015 MTAA 14 7

Beam Characteristic Neutron Beam Spectrum 10 8 E φ [MeV cm 2 s 1 ] 10 7 10 6 10 5 10 4 E 2.1 MeV φde 10 8 cm 2 s 1 α f /α t > 2 10 4 10 3 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 10 0 10 1 E [kev] Fast neutron beam energy spectrum at FaNGaS T.H. Randriamalala August 28, 2015 MTAA 14 8

FaNGaS Spectrometer n-type HPGe:GMX50-83, ORTEC Data acquisition: DSPEC-50, ORTEC + GammaVision-32 Spectrum evaluation: HYPERMET-PC Efficiency -4 10-5 10 133 Ba 35 60 Cl(n,γ) Co Cs Eu 137 152 2 10 36 Cl 3 10 Energy [kev] 4 10 Detector eciency for prompt γ-rays (67 cm away from the detector) T.H. Randriamalala August 28, 2015 MTAA 14 9

Background 106 2 H-D.E. N 14 74 Ge 72 Ar, Ge In 2 116 Ge C 13 41 70 Al Pb 27 Pb 65 Cu 70 Ge 207 207 207 Cu 63 Counts Pb 72 Ge 56,56Mn Ge 104 74 206 72 Ge Pb 74 Ge Counts Pb Annih. B 104 11 10 76 207 Ge 71m 75 m Ge Ge { H-S.E. X 5 103 103 100 200 300 400 500 Energy [kev] 600 700 800 900 1000 1100 1200 1300 1400 Energy [kev] 1500 1600 1700 -S.E. 55 -D.P. -S.E. -D.P.-S.E. 55 Counts D.E. 13 C -D.E. 14 N 12 C C C-S.E. 13 12 103 208 14 Counts N Pb 104 -D.P.-D.E. 103 105 -S.E. -S.E. 2 H 0 102 10 102 1 2000 2500 3000 4000 4500 5000 5500 6000 6500 7000 7500 Energy [kev] Total count rate beam on: 4000 cps Strong lines: H(110 cps), B(36 cps), (5 cps) Fast neutron rate at the detector 10 s 1 (from Ge(n, n0 γ) Ge) 74 T.H. Randriamalala 3500 Energy [kev] 8000 8500 9000 74 August 28, 2015 MTAA 14 10

Sample Properties Foil Θ [mm] m [g] purity [%] Be 0.2 99.40 Al 0.25 0.435 99.99 Ti 0.10 0.366 99.99 0.25 1.384 99.99 Co 0.25 1.580 99.95 Ni 0 3.026 99.99 Cu 1.00 5.429 99.99 Zr 0.25 1.077 99.94 Nb 0.25 1.412 99.99 Rh 0.10 0.802 99.80 Pd 0.025 0.194 99.95 Cd 0.10 2.663 99.99 In 0.2 99.40 W 0.10 0.715 99.99 Pt 0.025 0.339 99.95 Pb 0.25 4.237 99.98 U 0.25 0.4036 99.98 T.H. Randriamalala August 28, 2015 MTAA 14 11

Sample Properties Foil Θ [mm] m [g] purity [%] Be 0.2 99.40 Al 0.25 0.435 99.99 Ti 0.10 0.366 99.99 0.25 1.384 99.99 Co 0.25 1.580 99.95 Ni 0 3.026 99.99 Cu 1.00 5.429 99.99 Zr 0.25 1.077 99.94 Nb 0.25 1.412 99.99 Rh 0.10 0.802 99.80 Pd 0.025 0.194 99.95 Cd 0.10 2.663 99.99 In 0.2 99.40 W 0.10 0.715 99.99 Pt 0.025 0.339 99.95 Pb 0.25 4.237 99.98 U 0.25 0.4036 99.98 T.H. Randriamalala August 28, 2015 MTAA 14 11

Benchmark Spectrum Found γ-rays are matched with γ-rays transition based on ENSDF a 83 γ-rays found: 54 (7), 56 (72), (4) Counts 6 10 5 10 4 10 122 230 366 537 650 847 7 852 956 1038 1090 1153 1238 1303 1408 1551 1671 1771 1811 1852 2035 2095 2214 2274 2426 2523 2599 2658 2759 2983 3121 3201 3167 3254 3371 3449 3549 3601 3664 3764 3813 56 54 4033 a http://www.nndc.bnl.gov/ensdf/. 3 10 0 500 1000 1500 2000 2500 3000 3500 4000 Energy [kev] Prompt γ-rays from iron sample irradiation T.H. Randriamalala August 28, 2015 MTAA 14 12

Benchmark Analysis Found γ-rays Isotope Demidov 3 FaNGaS Missed by FaNGaS 54 4 7 0 56 37 72 3 59 Co 53 79 3 58 Ni 33 93 4 63 Cu 46 120 6 3 A.M Demidov et al., ATLAS of Gamma-Ray Spectra from Inelastic Scattering of Reactor Fast Neutrons Moscow (1978). T.H. Randriamalala August 28, 2015 MTAA 14 13

Benchmark Analysis I/I Dem. 1.0 56 0.0 1.0 1.0 59 Co 0.0 1.0 1.0 58 Ni 0.0 1.0 1.0 63 Cu 0.0 1.0 0 500 1000 1500 2000 2500 3000 3500 4000 E [kev] Relative γ-ray intensities compared to those of Demidov T.H. Randriamalala August 28, 2015 MTAA 14 13

Rate Comparison Measured count rate: R meas = R N = C Nεκt meas C : the counts in the peak ε: the eciency t meas : the measurement time κ: a correction factor (sample self-shielding) Calculated count rate: R calc = R N = σ p (E)φ(E)dE σ p : the γ-ray production cross section calculated from TALYS 3 φ: the determined ux 3 http://www.talys.eu/. T.H. Randriamalala August 28, 2015 MTAA 14 14

Rate Comparison 10-16 56 meas. 56 calc. 54 meas. 10-17 54 calc. R [ atom 1.s 1 ] 10-18 10-19 10-20 1.0 R/R c 0.0 1.0 500 1000 1500 2000 2500 3000 3500 4000 E [kev] T.H. Randriamalala August 28, 2015 MTAA 14 15

Rate Comparison 10-16 59 Co meas. 59 Co calc. 10-17 R [ atom 1.s 1 ] 10-18 10-19 10-20 1.0 R/R c 0.0 1.0 0 500 1000 1500 2000 2500 3000 E [kev] T.H. Randriamalala August 28, 2015 MTAA 14 15

Rate Comparison 10-16 58 Ni meas. 58 Ni calc. 10-17 R [ atom 1.s 1 ] 10-18 10-19 10-20 1.0 R/R c 0.0 1.0 0 500 1000 1500 2000 2500 3000 3500 4000 E [kev] T.H. Randriamalala August 28, 2015 MTAA 14 15

Rate Comparison 10-16 63 Cu meas. 63 Cu calc. 10-17 R [ atom 1.s 1 ] 10-18 10-19 10-20 1.0 R/R c 0.0 1.0 0 500 1000 1500 2000 2500 3000 E [kev] T.H. Randriamalala August 28, 2015 MTAA 14 15

Conclusion Neutron inelastic (prompt) γ-rays were measured using 10 8 n cm 2 s 1 with Ē = 2.1 MeV at FaNGaS. FaNGaS can resolve a larger part of the γ-rays (cp. Demidov 1978) Measured intensity and count rate of γ-rays agreed with existing data. Outlook γ & n background reduction Total and partial cross sections determination Build an (n, n γ) catalog of elements T.H. Randriamalala August 28, 2015 MTAA 14 16

FaNGaS Collaboration: FZ-Jülich GmbH: M. Rossbach, T. Randriamalala, E.Mauerhofer MLZ, Garching: Zs. Révay, P. Kudejova, S. Söllradl, F. Wagner, C. Genreith FaNGaS is supported by BMBF. Project Nr: 02S9052A T.H. Randriamalala August 28, 2015 MTAA 14 17

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Foils Mass [g] Reaction E thr [MeV ] R [/atom s] Al 0.437 27Al(n, p) 27 Mg 1.896 (5.40 ± 0.14) 10 19 27Al(n, α) 24 Na 3.249 (1.22 ± 0.04) 10 19 Ti 0.376 46Ti(n, p) 46 Sc 1.619 (1.87 ± 0.35) 10 18 47Ti(n, p) 47 Sc 0.075 (2.19 ± 0.05) 10 18 48Ti(n, p) 48 Sc 3.276 (5.45 ± 0.21) 10 20 1.384 56(n, p) 56 Mn 2.965 (1.99 ± 0.07) 10 19 Co 1.580 59Co(n, α) 56 Mn 1.500 (4.00 ± 0.15) 10 20 Ni 3.026 58Ni(n, p) 58 Co 0.490 (9.67 ± 0.21) 10 18 61Ni(n, p) 61 Co 49 (2.45 ± 0.14) 10 19 Cu 5.429 65Cu(n, p) 65 Ni 1.376 (6.14 ± 0.37) 10 20 Rh 0.802 103Rh(n, n ) 103m Rh 0.040 (4.05 ± 0.36) 10 17 In 2.412 115In(n, n ) 115m In 0.339 (2.42 ± 0.04) 10 17 1.384 58(n, γ) 59 (3.22 ± 0.29) 10 17 Co 1.580 59Co(n, γ) 60m Co (9.78 ± 0.22) 10 18 In 2.412 115In(n, γ) 116m In (5.03 ± 0.08) 10 17 W 0.715 186W(n, γ) 187 W (3.86 ± 0.10) 10 17 Au 63 197Au(n, γ) 198 Au (9.59 ± 0.09) 10 17