tailieunhanh - Đề thi khóa 33 trường ĐHSP năm 4 khoa vật lý - Vật lý neutrong (2)

Tham khảo tài liệu 'đề thi khóa 33 trường đhsp năm 4 khoa vật lý - vật lý neutrong (2)', khoa học tự nhiên, vật lý phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Interaction of Neutrons with Matter Problem 1. Two beams of 1-eV neutrons intersect at an angle of 90 . The density of neutrons in both beams is 2x10 n cm3. a Calculate the intensity of each beam. b What is the neutron flux where the beams intersect Problem 2. A monoenergetic beam of neutrons. 4x1 o10 n s cm2 impinges on a target 1 cm2 in area and cm thick. There are atoms per cm3 in the target and the total cross-section at the energy of the beam is b. a What is the macroscopic cross-section b How many neutron interactions per second occur in the target c What is the collision density collision rate Problem 3. The p- emitter28Al half-life min can be produced by the radioactive capture of neutrons by 28A1. The cross-section for this reaction is b. Suppose that a small aluminum target is placed in a beam of neutrons 3xl08 n s cm2 which strikes the entire target. Calculate a The neutron density in he beam b The rate at which 28A1 is produced. Problem 4. A beam of 2-McV neutrons is incident on a slab of heavy water DjO . The total cross-section of deuterium and oxygen at this energy are and b respectively. a What is the macroscopic total cross-section of heavy water at 2 MeV b How thick must the slab be to reduce the intensity of the uncollided beam by a factor of 10 c If an incident neutron has a collision in the slab what is the relative probability that it collides with deuterium