Response matrix of an extended Bonner sphere system

Response functions of a Bonner sphere spectrometer calculated with GEANT4

“…[17]. The diameters of the (white) PE spheres with density r ¼ 0:95 g=cm 3 were 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6,7,8,9,10,11,12,15 in., respectively. The inner black sphere with density r ¼ 0:96 g=cm 3 and diameter 1.3 in.…”

“…Depending on the fluence rate of the neutron field, different thermal neutron detectors are used. So-called ''active'' detectors such as 3 He-proportional counters [5][6][7][8], are used at low neutron fluence rates while so-called ''passive'' and less sensitive detectors such as gold foils [9][10][11][12][13][14][15], are preferred to measure high neutron fluence rates. For example, 3 He-counters are presently being used for continuous measurements of secondary neutrons from cosmic radiation at mountain altitude or in Spitsbergen [7,16].…”

Robust Design of Artificial Neural Networks Methodology in Neutron Spectrometry

“…[39] Spectral information must generally be obtained from passive detectors which respond to different ranges of neutron energies such as the multispheres Bonner system or Bonner spheres system (BSS). [40][41][42] BSS system, has been used to unfold the neutron spectra mainly because it has an almost isotropic response, can cover the energy range from thermal to GeV neutrons, and is easy to operate. However, the weight, time consuming procedure, the need to use an unfolding procedure and the low resolution spectrum are some of the BSS drawbacks.…”

Evolutionary Artificial Neural Networks in Neutron Spectrometry

“…Equation 1 is an ill-conditioned problem wich has an infinite amount of solutions Although there is a wide range of different devices used for neutron spectrometry, the majority of the instruments can be grouped together into a small number of broad categories, each one based on a common underlying technique (Matzke, 2003;McDonald et al, 2002;Thomas, 2004). Among the many available neutron spectrometry techniques, the multisphere or Bonner sphere spectrometer (BSS) system is the most used for radiation protection purposes (El Messaoudi et al, 2004;Lacoste et al, 2004;Vylet, 2002), due to advantageous characteristics as wide energy range (from thermal to GeV neutrons), large variety of active or passive thermal sensors allowing adapting the sensitivity to the specific workplace, good photon discrimination and simple signal management. Disadvantages are the poor energy resolution, which does not allow appreciating fine structures as narrow peaks, the weight, and the need to sequentially irradiate the spheres, requiring, in general, long exposure periods (Bedogni et al, 2007).…”