| 摘要 |
FIELD: electrical engineering. ^ SUBSTANCE: invention can be used for analysing objects through radiation methods using neutron, X-ray or gamma radiation. The radiographic device contains a thermal neutron source in which in front of a fast neutron source, a moderating block is installed, made from polyethylene in form of a hollow cube. Inside the moderating block there is a converter. Between the end surface of the converter and the inner surface of the moderating block a polyethylene layer is deposited, forming a cavity. A converter-reflector, gamma shielding layer and a protective layer for absorbing thermal and fast neutrons are put on the surface of the moderating block in series. The cross section of the collimator input channel coincides with the cross section of the cavity. The collimator is put in front of the input channel of the cavity. Another shield from a series of gamma shielding layer and protective layer for absorbing thermal and fast neutrons is put on the length of the collimator. This extra shield is joined to a measuring chamber, made in form of a frustum pyramid, the smaller base of which is directly in front of the output channel of the cavity. The walls of the measuring chamber are made from gamma shielding blocks and protective blocks for absorbing thermal and fast neutrons. Inside the measuring chamber there is a table for the test sample, a detecting system and a collimator, whose base is directly in front of the test sample. ^ EFFECT: increased efficiency of converting fast neutrons into thermal neutrons, shorter exposure time, reduced effect of background signal, improved quality of received images. ^ 3 dwg |
