10B4C Multi-Grid as an Alternative to 3He for Large Area Neutron Detectors

Correa Magdalena, Jonathan

2013
Prensas Universitarias de Zaragoza Zaragoza
ISBN: 978-84-15770-39-8

Resumen: Due to their specific properties, thermal neutrons are used extensively to study the structure and dynamics of matter. However, these properties make their detection dificult. A nuclear interaction is therefore used to create secondary charged particles to be detected instead of the incoming neutron. For more than three decades, 3He has been the main neutron converter used. However, primarily due to Homeland Security programs in the United States, the accumulated stockpile of 3He has decreased dramatically in the last few years. Production no longer meets the demand and consequently there is an acute shortage of 3He. The needs of future neutron facilities, such as the European Spallation Source (ESS) together with the instrument suite renovation programmes currently being undertaken at existing sources such as J-Parc, the Spallation Neutron Source (SNS) and the Institute Laue Langevin (ILL) mean that alternative solutions will have to be found rapidly for Large Area Neutron Detectors (LANDs). In this context, the causes and consequences of the 3He crisis are examined. The first instruments to be afeected by the shortage of 3He are those covering large areas, particularly Time-of-Flight (ToF) spectrometers. The principal requirements for a neutron detector installed in this type of instrument are analysed, using the IN5 cold spectrometer at the ILL as a benchmark. The scientific community is currently examining three difeerent techniques as possible alternatives to 3He: BF3 gas counters, scintillators coupled to Wavelength Shifting Fibres (WSF), and boron-lined detectors. Specific problems associated with each of these solutions are described. Three difeerent types of radiation matter interactions need to be examined to understand how neutron detectors work...

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DOI: 10.26754/uz.978-84-15770-39-8