Research On The Measurement Of Fluxes And Spectra Of Charge Particles In Space

Development of aerospace technology is an important aspect for human entering the space, but the radiation belts in space which include the electromagnetic irradiation and charged particles irradiation greatly limited the pace for marching space. For the charge particles irradiation, there are electrons, protons and high energy heavy ions irradiation mainly. The charged particles irradiation will cause a serious effects on the materials, electronic devices and other accessories of aircraft, such as single event upset (SEU), single event latch-up (SEL), single event burn-up (SEB) and total doses effects. Our research aims to research and design an spectrometer-identificator to simultaneously or separately detect the fluxes and spectra of protons, alpha particles, oxygen and iron ions distributed in space. This instrument can automatically send the information from the irradiation belts based on the detecting results, which will provide an foundation for the reinforcement of aircraft irradiation resistance.A multi-functional spectrometer-identificator is developed to measure fluxes and spectra of protons, alpha particles, oxygen and iron ions in space. A multi-laminated structure telescope and a modified fast response electronics system were adopted to design a multi-functional charged particle spectrometer-identificator for near-earth space environment studying. The telescope system for this instrument consists of three Au-Si surface barrier detectors with different thickness and an scintillation CsI (Tl). Owing to adopting the AE-E method in identification of particles and modified fast response electronics system in data acquisition and processing unit, the spectrometer can be used to simultaneously or separately detect the fluxes and spectra of protons with energy of 1-200 MeV, alpha particles with energy of 1-200 MeV/u (nucleon), oxygen ions with energy of 1.7-496 MeV/u and iron ions with energy of 2.5 MeV-1.0 GeV/u. The basic principle of operation for such device is as follows: when a charged particles injected into the detectors, pulses from the detectors areamplified by charge-sensitive preamplifiers and main amplifiers, then applied to amplitude discriminator shapers. The inputs of the discriminators are adjusted to record pulses with energies greater than the threshold. The signal from the discriminators is fed to ADC circuit. The signal was conversed by ADC from analogy to digital signal and memorized in 80C31 unit.The performance testing and energy calibration of this instrument were performed on HI-13 tandem accelerator in China Institute of Atomic Energy. The detectors were irradiated with a mono-energetic beam of charged particles, which are protons, alpha particles, oxygen and iron ions. The channel number was determined from the total absorption peak. The irradiation experimental results show that the resolution of thin detector â–³E1 is higher than that of other thick detectors for ex-particles and protons detection. Energy calibration for a-particles was completed with multiplication factor 1/3. Energy calibrations of a-particles in detector â–³E1 and â–³E1, are 0.107 MeV and 0.123 MeV per channel, respectively. Energy calibration for protons was completed with multiplication factor 1. The energy calibration of proton in detector â–³E2, is 0.0167MeV per channel. The energy calibration is more accuracy and almost constant with the injected energy of proton. However, the energy calibration in â–³E1 detector has a slight decrease with increasing the energy of protons. The reasons are attributed to the non-uniformity in thickness and disturbing from surrounding r,b ray and secondary particles. The scintillation CsI was also calibrated with protons of 15, 20, 23 MeV. The average energy calibration is 1.047 MeV per channel. Energy calibration for heavy ions was completed with multiplication factor 1/12.75. The energy calibration is around 1.1 MeV per channel for oxygen ion and iron ions when energy deposition is less than 50 MeV in each detector. The amplifying amplitude for the electronics sy...