Investigation of Spodumene TLD Response to Monoenergetic Neutron Fields

The application of ionizing radiations in different fields requires the use of equipment capable of detecting their presence or quantifying them. Detectors of the most different shapes, composition and characteristics are required to cover the full range of application of ionizing radiations. At present, thermoluminescent detectors (TLD) are the most widely employed for individual gamma monitoring. Thermoluminescence (TL) is a process in which heated insulator or semiconductor emits the light in correlation with previous absorption of energy from ionizing radiation [1]. Several materials that present intense TL are used as TLD to measure radiation doses for manifold applications [2], including neutron dosimetry, where nowadays a sufficiently reliable method, covering the whole range of neutron energies, does not exist [3]. For neutron dosimetry applications, elements with large neutron cross section (as 6Li and 10B for thermal neutrons [4]) are added to the basic components of TLD. Generally, because the neutron cross section depends markedly on the neutron energy, there are different detectors for thermal neutrons and fast neutrons. The 10B(n,α)Li reaction is most often used for detection of thermal neutrons, while the reaction 6Li(n,α)3H is also used in the neutron albedo detectors. In this work, a series of preliminary measurements, investigating the neutron response of spodumene TLD crystals (LiAlSi2O6), is described. As far as we know, TL response of any type of spodumene TLD to neutrons radiation has never been reported. These crystals emit intense light with a wavelength around 600 nm, when irradiated with high doses from X and gamma rays, or beta particles from 90Sr-90Y source, with the main TL peak in a temperature range suitable for dosimetric applications [5-8]. The feasibility to use boron as a spodumene dopant has been also investigated.