Design And Implementation Of β, X, γ-rays Electronic Personal Dosimeter

β-rays’ effects to human has gain more widely attention in personal ionizing radiation dosimetry, beyond monitoring dose of X-rays and γ-rays.Among the related devices, active personal dosimeters, also known as electronic personal dosimeters, are becoming popular, with their immediate display and feedback, compared with traditional passive personal dosimeters like thermo-luminescent ones.But some current electronic personal dosimeters have poor response ability to betaand clinical X-rays, especially the pseudo-low display value in pulsed X-rays fields common in clinic. This is mainly rely on the response time and energy response performance of device, which are the main focuses of this thesis.For detectors satisfied the portable requirements, compact novel photo-electric device, i.e. silicon photo-multiplier, was selected, coupling to an proper inorganic scintillator, to compose scintillation detector. When compared with the commonly-used gas detectors and silicon semiconductor detectors, scintillation detectors possess advantages of high detection efficiency and higher signal-to-noise ratio simultaneously. Moreover, the introduction of the silicon photo-multiplier broke the limitation of traditional scintillation detector in portable applications, cause by the large size and fragileness of vacuum photo-multiplier tube in it.For the detector’s over-response phenomenon to low-energy photons, covering the detector with compensation materials can’t be implemented, because of the high restriction of material thickness from beta-rays detection. In my solution, the whole energy range was divided into three sections, based on the pulse signal magnitude differences, each with an individual coefficient.The response time depends on data smoothing algorithm. For simultaneous obtain both stable display values and fast response time, rather than simple compromise between the contradictory requirements, an algorithm with auto-switched parameters was designed and implemented in the portable embedded system.Finally, a prototype of the electronic personal dosimeter was implemented, which can detect beta-, X-, gamma-rays simultaneously, with compensated energy response that compliant with the related regulations, as well as fast response time in pulsed radiation fields.