The Transmission Of Low Energy Neutron Beam Through Bi Polycrystal Filter

An experiment of the low energy neutron beam transmission through Bi polycrystal filter of 15,3 cm length at room temperature of (293K) was carried out using flight time neutron spectrometer SV5c(TOF) and triple axis neutron spectrometer SV4(DAS), The transmission of neutron beam using time of flight neutron spectrometer SV5c(TOF) at wavelength interval 2 - 4AA was varied 20% to 50%, and at wavelength interval of 4 - 10AA was varied from 50% to 70%, while the transmission of neutron beam using triple axis neutron spectrometer SV4(DAS) at wavelength interval of 4 -10AA was varied 70%. This experiment was in a good agreement with the result of S. Menardi et-al experiment using time of flight neutron spectrometer through Bi quasi single crystal filter of 20 cm thick at liquid Nitrogen temperature (77K), where the transmission neutron beam at wavelength interval of 1,8 - 2.9AA was varied 30%, and at wavelength bigger than 4AA was varied from 60% to 70%. Thought the Bismuth polycrystal filter is good enough to take the place of the Bismuth quasi single crystal material neutron beam filter at wavelength interval ?λ =4,0AA to ?λ = 10,0AA of which difficult to be found