Research On Key Technology Of Diamond α And γ Particle Radiation Detector

Diamond with extraordinary properties,such as low dielectric constants,high carrier mobility,and extremely high thermal conductivity,is an ideal choice for the next generation radiation detectors.With the continuous development of chemical vapor deposition technology（CVD）,radiation detectors based on diamond materials have obvious advantages compared with other types of semiconductor detectors,and have excellent performance in high-energy particle detection,energy spectrum testing and other application scenarios.（Ⅰ）Developed a preparation process based on single-crystal CVD diamond radiation detector.Firstly,the diamond material was characterized by Raman spectroscopy and AFM,and the selection of"detector-grade"diamond crystals was completed.The diamond MEMS process was developed,and the magnetic sputtering protection fixture and detector packaging were designed,with the volume of the encapsulated detector being 9.28 cm³.（Ⅱ）A detector irradiation test system was built to detectαandγradiation.At an electric field of 0.6 V/μm,a low current dark value of 80 p A was measured,and its linear current-voltage characteristics show good ohmic contact characteristics.The detector’s pulse speed,photocurrent,and energy resolution were tested using 5.486 Me V ²⁴¹Am and 12000 Ci ⁶⁰Co sources.The time response of the detector toαparticles is fast,with a rise time of 240 ps,a fall time of 630 ps,and a pulse width of 1.6 ns.Besides,the energy resolution forαparticles was5%.For sensingγradiation,the photocurrent rose rapidly to 700μA when the radiation flux reached 240 Gy/h.The time response toγradiation showed a pulse width of 176 ns.（Ⅲ）The design of the charge-sensitive preamplifier and main amplifier schematic has been completed based on the characteristics of the diamond radiation detector.The charge-sensitive preamplifier is composed of operational amplifiers,and the main amplifier consists of two stages of S-K filtering circuits and a second amplifying circuit with polarity conversion.Finally,the feasibility of the design is verified through Multisim simulation tests and synchronization tests with the detector.The output signal of the diamond radiation detector is10 m V by the charge-sensitive preamplifier,and further amplified to 28 m V Gaussian pulse by the main amplifier.