Problem1.
The mass attenuation coefficient for concrete (density r= 2.35 g/cm3) for 600 keV photons is 0.08 cm2/g.
a) What is the probability that a 600 keV photon, normally incident on a thick, flat concrete shield will reach a depth of 15 cm without having an interaction?
b) What is the probability that an incident photon will reach a depth of 30 cm without interacting?
Problem2.
Assuming that you are designing a Boron (10B) slab shield on the outer region of a neutron source 'pig' to hold a neutron source. Assume that the neutron flux is 100% thermal at the outer surface of the pig. The capture thermal cross section of the Boron is Sigma=759 barn.
a) What thickness of boron shield is required that no more than 1% of the thermal flux penetrates the outer surface of the shield?
b) Calculate the absorption rate?
Problem3.
A GM counter has a window diameter of 5 cm. A point source is placed 6 cm from the surface of the window.
a) What is the geometrical efficiency of this set-up?
b) A particle of 1MeV ionizes the gaz inside the tube, what is the primary number of (e-, ions) create in the gas if one pair of (e-, ion) requires 20eV.
c) 2 particles with different energies hit the GM, how many pulses you can see at the output of the detector? Can you differentiate between the 2 particles in terms of energy?