Institut fr Kern und Teilchenphysik Neutron activation of

Institut für Kern- und Teilchenphysik Neutron activation of materials relevant for GERDA-meeting - Padova Alexander Domula March 12 th 2009

❶ Neutron Introduction/Activation Experiments ❷ Neutron-Activations with 14 Me. V Neutrons ❸ Activation of copper and stainless steel components 2

Neutron Activation Experiments Neutron sources: • radioactive sources - radioactive a-sources (210 Po, 241 Am, …) - 7 Li(a, n)10 B, 9 Be(a, n)12 C, 13 C(a, n)16 O, … - 241 Am-9 Be source E midd = 4, 46 Me. V n • nuclear fission - Maxwell- or Wattspectra; E(j. Emax) ≈ 1 Me. V 3

Neutron Activation Experiments • accelerators - charged particle reactions 7 Li(p, n)10 B (Q=-1, 646 Me. V) 2 H(d, n)3 He (Q=3, 266 Me. V) 3 H(d, n)4 He (Q=17, 586 Me. V; En≈14, 064 Me. V) - Bremsstrahlung (g, n)-reactions • cosmic ray reactions 4

Neutron Activation Experiments inelastic scattering 74 Ge(n, n‘)74 Ge* Neutron capture 74 Ge(n, g)75 m. Ge 5

Neutron Activation Experiments fast Neutron activation 59 Co(n, p)59 Fe 65 Cu(n, 2 n)64 Cu 63 Cu(n, a)60 Co 76 Ge(n, p)76 Ga 6

Neutron Activation Experiments competing reaction channels • one product of different isotopes • one product of different reaction channels 7

Neutron Activation Experiments • spectroscopy of Neutron fields • dosimetry • measurement of Neutron-reaction cross-sections • exploring nuclear level schemes • material analysis 8

Activation Experiments at 14 Me. V TUD Neutron Generator motivation: • GERDA meeting at Nov 2008 „Cosmogenic Radionuclides in stainless steel and copper“ 1. stainless steel 2. copper G. Heusser, M. Laubenstein 9

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Activation Experiments at 14 Me. V TUD Neutron Generator • chemical composition of 1. 4571 stainless steel (X 6 Cr. Ni. Mo. Ti 17 -12 -2) Element Max. fraction % C Si Mn P S Cr Mo Ni Ti 0, 08 1, 00 2, 00 0, 045 0, 015 18, 5 2, 5 13, 5 0, 7 + rest consists of Fe • activation experiments at neutron facility at FZD Rossendorf - stainless steel components (1. 4571): Fe, Mo, Ni, Ti activated elementwise 11

Activation of stainless steel components (Fe) • end irradiation Feb 12 th 2009, 16: 00 • short living nuclides - Feb 12 th 2009, 17: 33: 15, t. L = 580 s E [ke. V] Nuclid 846, 8 56 -Mn 1811, 38 56 -Mn 2114, 04 56 -Mn 2524, 18 56 -Mn 3371, 28 56 -Mn 12

Activation of stainless steel components (Fe) • long living nuclides - Feb 27 th 2009, 11: 42: 13 t. L = 256‘ 979 s E [ke. V] Nuclid 121, 38 57 -Co 319, 79 51 -Cr 510, 99 Annihilation 810, 76 58 -Co 834, 9 54 -Mn 13

Activation of stainless steel components 54 • two ways to get Mn 56 Fe(n, 2 np)54 Mn 54 Fe(n, p)54 Mn not mentioned 14 Me. V Neutrons! 14

cross section vs. Neutron Flux • activation 2, 6 times higer for 56 Fe(n, 2 np)54 Mn reaction 54 Fe(n, p)54 Mn also important 15

Activation of stainless steel components (Mo) • long living nuclides t. L = 165‘ 840 s E [ke. V] Nuclid 140, 02 99 -Mo / 99 m-Tc 180, 5 99 -Mo 235, 49 95 m-Nb 765, 76 95 -Nb 777, 93 96 -Nb 934, 54 92 -Nb 1199, 89 96 Nb 1204, 88 91 m-Nb 1477, 38 93 m-Mo 16

Activation of stainless steel components (Ni) • short living nuclides t. L = 1‘ 750 s E [ke. V] Nuclid 121, 21 57 -Co 136, 88 57 -Co 127, 75 57 -Ni 510, 8 Annihilation 810, 58 58 -Co 847, 15 56 -Co ? 1377, 84 57 -Ni 1758, 27 57 -Ni 1920, 5 57 -Ni 17

Activation of stainless steel components (Ti) • long living nuclides t. L = 170‘ 465 s E [ke. V] Nuclid 158, 72 47 -Sc 174, 77 48 -Sc 510, 94 46 -Sc 888, 99 48 -Sc 983, 33 48 -Sc 1037, 35 46 -Sc 1120, 49 47 -Sc 1212, 82 48 -Sc 1312, 12 48 -Sc 18

Activation of Copper • end irradiation Feb 12 th 2009, 16: 00 • short living nuclides - Feb 12 th 2009, 17: 07: 24, t. L = 1‘ 239 s E [ke. V] Nuclid 366, 14 65 -Ni 510, 86 Annihilation 1115, 7 65 -Ni 1346, 18 64 -Cu 1482, 18 65 -Ni 19

Activation of Copper • long living nuclides - Mar 2 nd 2009, 12: 03: 33 t. L = 169‘ 995 s E [ke. V] Nuclid 121, 02 57 -Co 135, 03 57 -Co 510, 76 Annihilation 608, 50 214 -Bi 809, 73 58 -Co 1171, 96 60 -Co 1331, 05 60 -Co 1460, 30 40 -K 1763, 63 214 -Bi 2504, 83 S 60 -Co 2613, 64 208 -Tl 20

cobalt in copper ? 21

Cross sections • 59 Co(n, 2 n)58 Co visible 59 Co(n, x) only when 59 Co(n, a)56 Mn is 22

Activation of Cobalt • short living nuclides - t. L = 265 s E [ke. V] Nuclid 510, 92 Annihilation 810, 72 58 -Co 846, 76 56 -Mn 1099, 28 59 -Fe 1291, 85 59 -Fe 1811, 31 56 -Mn 2113, 97 56 -Mn 2524, 09 56 -Mn 3373, 84 56 -Mn 23

Summary 1. Neutron activation is a powerful tool to investigate radioisotope production 2. First samples of Fe, Ni, Mo, Ti, Cu and Co have been activated with 14 Me. V Neutrons 3. 54 Fe(n, p)54 Mn reaction can‘t be neglected for 54 Mn production on iron 4. Observed 57 Co by copper activation due to nickel within Cu 24

Next steps • activation of 1. 4571 stainless steel sample provided by G. Heusser • work towards cross section measurement • activation of chrome ? • Activation of Argon ? • Activation of any other Material of interest for GERDA ? 25