cosmogenic*ac,va,on* evaluaon - zzz.physics.umn.edu · produconrateinstainlesssteel*...
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Cosmogenic Ac,va,on Evalua,on
Chao Zhang and Dongming Mei University of South Dakota
Ac,va,on at sea level
• Targets are concerned • Produc<on rate • Exposure <me • Materials at risk • Shielding and protec<on
Targets are concerned • Xenon gas cylinders on the surface – Target for dark maBer searches
• Copper bricks, rods, sheets – Inner detector parts
• Ti vessel – Inner detector vessel
• Stainless Steel – Inner parts
• Teflon – Inner parts
Cosmogenic produc,on is only relevant to the inner parts due to a rela,ve low ac,vity comparing to natural radioac,vity
Geometry
• Xenon gas cylinder – Stainless steel: 12”D * 50”H with 0.3” in thickness – Xenon gas: 970psi gauge, density 0.3657 g/cm3. temperature 20 oC. Total mass in the cylinder: 30kg.
• Bulk volume: Cu, Ti, SSteel and Teflon – 10 cm in diameter and 10 cm in height
4
Input Muons • Modified Gaisser’s formula is used to sample muons right above the gas cylinder. Enery range spans from 1GeV to 50TeV. Total flux normalized to 0.0137054/cm2/s.
5
Input neutrons
Ø Thermal neutron flux adopted from simula<on results from MCNPX(Chris Hagmann, LLNL, 2012) with the energy range[1e-‐8, 4]MeV. Total flux normalized to 0.002/cm2/s.
6
Ø Fast neutron is taking measurement result “NY data” (M.S.Gordon, 2004) with energies [4, 2000]MeV. Total flux normalized to 0.00405231/cm2/s.
Produc,on rate in xenon (kg-‐1d-‐1)
Only produc,on of 127Xe is a concern
P2P networks: Methods and open problems
Hermanni Hyytiala
Agora Center, University of Jyvaskyla P.O. Box 35, FIN-40014 Jyvaskyla Tel.:
+358 14 260 1211
1 Introduction
Table 1
Isotopn(<4MeV) n(>4MeV) µ Total
(activation in Xenon gas, /kg/day) (/kg/day)
31H, 12.3y(β) 0 28.92 0.5921 29.51
8136Kr, 2.3e5y(γ,β, x) 0 0.0461 0 0.0461
10948 Cd, 462.6d(γ,β, x) 0 1.367 0 1.367
11350 Sn, 115.1d(γ,β, x) 0 6.504 0 6.504
11950 Sn, 293.1d(γ, x) 0 1.488 0 1.488
12451 Sb, 60.2d(γ,β, x) 0 1.586 0 1.586
12551 Sb, 2.8y(γ,β, x) 0 1.453 0 1.453
12152 Te, 154d(γ,β, x) 0 20.60 0.09868 20.70
12352 Te, 119.7d(γ,β, x) 0 17.93 0.1974 18.12
12553 I, 59.4d(γ,β, x) 0 76.14 0.3947 76.53
12953 I, 1.57e7y(γ,β, x) 0 76.23 0.2960 76.52
12754 Xe, 36.4d(γ,β, x) 0.6401 228.8 1.48 230.9
13354 Xe, 5.2d(γ,β, x) 11.08 85.58 1.678 98.34
13554 Xe, 9.1h(γ,β, x) 2.175 56.19 1.085 59.45
Email address: [email protected] (Hermanni Hyytiala).1
This work was funded by the Agora Center InBCT project.
Preprint submitted to Elsevier 14 July 2014
GEANT4: 127Xe: 4.6604E-‐04 Bq/kg LUX: (490+/-‐90)x10-‐6 Bq/kg
Produc,on rate in copper Table 1
Isotopn(<4MeV) n(>4MeV) µ Total
(activation in Cu, /kg/day) (/kg/day)
2211Na, 2.6y(γ) 0 0.01172 0.002692 0.01442
2613Al, 7.2e5y(γ) 0 0.01641 0.002692 0.0191
3214Si, 150y(β) 0 0.0633 0.002692 0.066
4019K, 1.3e9y(γ) 0 0.4806 0.02154 0.5022
4720Ca, 4.5d(γ) 0 0.1243 0 0.1243
4621Sc, 83.8d(γ) 0 1.048 0.02423 1.072
4721Sc, 3.3d(γ) 0 0.9824 0.01077 0.9931
4422T i, 63y(γ) 0 1.719 0.04846 1.767
5023V , 1.4e17y(γ) 0 3.318 0.02692 3.344
5124Cr, 27.7d(γ) 0 15.2 0.1212 15.32
5425Mn, 312.3d(γ) 0 11.68 0.07539 11.75
5526Fe, 2.7y(γ%) 0 53.66 0.2504 53.91
5926Fe, 44.5d(γ) 0 8.558 0.035 8.593
6026Fe, 1.5e6y(γ) 0 4.905 0.02962 4.934
5627Co, 77.3d(γ) 0 9.709 0.07539 9.784
5727Co, 271.8d(γ) 0 64.33 0.2612 64.6
5827Co, 70.9d(γ) 0 55.52 0.1669 55.68
6027Co, 5.3y(γ) 0.0163 63.12 0.2423 63.38
6530Zn, 244.3d(γ) 0 1.798 0.01885 1.817
Table 2
IsotopNeutron(<4MeV) Neutron(>4MeV) Muon Total
(activation in Teflon, /kg/day) (/kg/day)
74Be, 53.1d(γ) 0 15.8 0.04386 15.85
104 Be, 1.5e6y(β) 0 65.34 0.05483 65.4
146 C, 5.7e3y(β) 0.09009 0.009549 0 0.09964
2
Isotopes colored in red are at a cau,on
Produc,on rate in Ti Table 2
IsotopNeutron(<4MeV) Neutron(>4MeV) Muon Total
(activation in Ti, /kg/day) (/kg/day)
2211Na, 2.6y(γ) 0 0.1958 0 0.1958
2613Al, 7.2e5y(γ) 0 0.4056 0.01606 0.4217
3214Si, 150y(β) 0 1.511 0 1.511
4019K, 1.3e9y(γ) 0 20.98 0.1178 21.1
4720Ca, 4.5d(γ) 0 10.13 0.005354 10.14
4621Sc, 83.8d(γ) 0.3148 270.4 0.4336 271.2
4721Sc, 3.3d(γ) 1.831 385.4 0.5407 387.7
4422T i, 63y(γ) 0 95.94 0.4551 96.4
5023V , 1.4e17y(γ) 0 0.317 0.005354 0.3224
5124Cr, 27.7d(γ) 0 0.02331 0 0.02331
2
Isotopes colored in red are at a cau,on
Produc,on rate in stainless Steel Isotopes colored in red are at a cau,on Table 1
Isotopn(<4MeV) n(>4MeV) µ Total
(activation in SSteel, /kg/day) (/kg/day)
74Be, 53.1d(γ) 0 0.02093 0.006008 0.02694
104 Be, 1.5e6y(β) 0 0.102 0 0.102
146 C, 5.7e3y(β) 0.6028 1.162 0.006008 1.77
2211Na, 2.6y(γ) 0 0.225 0.003004 0.228
2613Al, 7.2e5y(γ) 0 0.8031 0.006008 0.8091
3214Si, 150y(β) 0 0.3244 0.01802 0.3424
4019K, 1.3e9y(γ) 0 2.6 0.03605 2.636
4720Ca, 4.5d(γ) 0 0.9706 0.003004 0.9736
4621Sc, 83.8d(γ) 0 8.429 0.03905 8.468
4721Sc, 3.3d(γ) 0 8.774 0.01502 8.789
4422T i, 63y(γ) 0 12.14 0.1472 12.29
5023V , 1.4e17y(γ) 0.2507 70.58 0.2403 71.08
5124Cr, 27.7d(γ) 3.94 282.5 5.338 291.8
5425Mn, 312.3d(γ) 3.527 222.2 0.6879 226.5
5526Fe, 2.7y(γ%) 3.776 621.8 18.3 643.9
5926Fe, 44.5d(γ) 0.1403 0.3061 0 0.4464
6026Fe, 1.5e6y(γ) 0 0.07848 0 0.07848
5627Co, 77.3d(γ) 0 14.68 0.09914 14.78
5727Co, 271.8d(γ) 0 79.12 0.1472 79.27
5827Co, 70.9d(γ) 8.148 80.07 0.3935 88.61
6027Co, 5.3y(γ) 0.001299 6.166 0.009012 6.176
2
Produc,on rate in Teflon Isotopes colored in red are may be at a cau,on
Table 1
Isotopn(<4MeV) n(>4MeV) µ Total
(activation in Cu, /kg/day) (/kg/day)
2211Na, 2.6y(γ) 0 0.01172 0.002692 0.01442
2613Al, 7.2e5y(γ) 0 0.01641 0.002692 0.0191
3214Si, 150y(β) 0 0.0633 0.002692 0.066
4019K, 1.3e9y(γ) 0 0.4806 0.02154 0.5022
4720Ca, 4.5d(γ) 0 0.1243 0 0.1243
4621Sc, 83.8d(γ) 0 1.048 0.02423 1.072
4721Sc, 3.3d(γ) 0 0.9824 0.01077 0.9931
4422T i, 63y(γ) 0 1.719 0.04846 1.767
5023V , 1.4e17y(γ) 0 3.318 0.02692 3.344
5124Cr, 27.7d(γ) 0 15.2 0.1212 15.32
5425Mn, 312.3d(γ) 0 11.68 0.07539 11.75
5526Fe, 2.7y(γ%) 0 53.66 0.2504 53.91
5926Fe, 44.5d(γ) 0 8.558 0.035 8.593
6026Fe, 1.5e6y(γ) 0 4.905 0.02962 4.934
5627Co, 77.3d(γ) 0 9.709 0.07539 9.784
5727Co, 271.8d(γ) 0 64.33 0.2612 64.6
5827Co, 70.9d(γ) 0 55.52 0.1669 55.68
6027Co, 5.3y(γ) 0.0163 63.12 0.2423 63.38
6530Zn, 244.3d(γ) 0 1.798 0.01885 1.817
Table 2
Isotopn(<4MeV) n(>4MeV) µ Total
(activation in Teflon, /kg/day) (/kg/day)
74Be, 53.1d(γ) 0 15.8 0.04386 15.85
104 Be, 1.5e6y(β) 0 65.34 0.05483 65.4
146 C, 5.7e3y(β) 0.09009 0.009549 0 0.09964
2
Comparison with ACTIVIA for some isotopes
Isotopes Geant4 (Bq/kg) (USD)
ACTIVIA (Bq/kg) (VK)
Experiments (Bq/kg) (LUX)
127Xe (in Xe) 4.7x10-‐4 7.2x10-‐5 (4.9±0.9)x10-‐4 133Xe (in Xe) 7.0x10-‐9 1.1x10-‐9 (5.0±0.5)x10-‐9
60Co (in Cu) 4.6x10-‐5 4.7x10-‐5
46Sc (In Ti) 1.2x10-‐3 4.6x10-‐4
57Co in (in SS) 3.4x10-‐4 4.2x10-‐4
Summary
• All isotopes produced by cosmogenic processes are compared with ACTIVIA
• Exposure <me – The <me on the surface needs to be minimized.
• Materials at risk – Valida<on of codes needs to be performed
• Shielding and protec<on – Needs a reliable MC code to design