per unit time through the reactions in a silver plate. Assume that
a silver plate weighs 10 g and that the neutron flux density, Φ, is
1010 neutrons/(m2 · s). The thermal absorption cross sections for
the isotopes are σa( 107Ag) = 35 b and σa( 109Ag) = 89 b
- 1 Calculate The Number Of 108ag And 110ag Nuclei Produced Per Unit Time Through The Reactions In A Silver Plate Assume 1 (82.53 KiB) Viewed 52 times
thermal neutrons will pass through the cover?
3.We now want to estimate the efficiency of paraffin for slowing
down the neutrons. The general chemical formula for paraffin is
CjH2j+2. We can use j = 58 and the paraffin density ρparaffin = 900
kg/m3 . Remember that neutrons lose on average half of their energy
in collisions with hydrogen nuclei. The energy loss in collisions
with carbon is so much smaller, that the effect of carbon is
negligible. In this estimation it is assumed that the neutrons are
moving in the same direction all the time, which in reality
certainly is not true.1 Also assume that the neutron scattering
cross section against hydrogen is independent of the neutron
energy, with σs = 20 b. This is true for a rather large energy
interval, see Fig. 12. Estimate the number of collisions needed in
paraffin to decelerate a neutron from 5 MeV to thermal energy
(0.025 eV). Also calculate the neutron mean free path in paraffin
and an upper limit for the paraffin thickness needed to moderate
the neutron.
4.
For the final activation to measure the half-lives, the time
needed to obtain an activation of around 90 % of saturation has to
be determined. This time is dependent on the halflife of the
activated isotopes. The most long-lived of the silver isotopes has
a half-life of less than 3 minutes. Estimate the activation time
needed using this knowledge.
Please answer as many as possible thank you!
Toto 1010 Toin 32m Tip 2.80 im 541 106Cd. 1 10m 18m 4. 1h 35m0.97% 11540.66% 159 0.314.54% 12us 2 1m 3.3 14d Toen 11010 11110 113In 1141 "In 1151 n 6.2n 58m 209 4.2 4.9h 15m 4.29 435 1.2 4.452.23 SOS 40m 1.3m 1.2h 7.711 1.7h sod 1.5h а Tord 108cd Tod 11000 111 112 113 114cd5cd 2.6E17y 6.5h 0.89% 1.3 12.49% 12.8424.13% 7.7E 28.73% 14y 450 15 110 Ag "Ag 112 Ag 114A Ag 1.2h 41d 24m 51.8 2.4n 48.16 255 7.50 3.1h 5.4h 4. 7.21 8.30 145 184 40s sod 1.1m 1.1m 1.5$ 104Pd 105 106d 109 Pd 110Pd "11Pd T12Pd113 Pd 11.14% 22.33% 27.33% 6.5E 26.46% 14h 11.72% 23m21h 1s 4.71 5.Sh 3005 h 103Rh 70RM TORTORA TO'Rh TOBRE TORTOR RhRh 18m. 106AB TAS 101 DE TOSAS 109 48 TISA TOPd 10pd Figure 11: Extract from chart of the nuclides around the stable Ag isotopes. 11 1000 100+ Cross-section I 10 1E-10 1E-9 1E-8 157 156 1E-5 15-4 0,001 001 0,1 1 10 Incident energy (MeV) Figure 12: Neutron scattering cross section for hydrogen.