Thermal ion mass discrimination is one of the key techniques for the space plasma detection.In order to measure the energy spectra and composition of space plasma,the Thermal Ion Mass Spectrometer (TIMS) utilizes a hemisphere electrostatic analyzer accompanied with a time of flight unit based on ultra-thin carbon foil.It has been used broadly in space plasma measurement.Three key techniques,such as 5 mV high resolution sweeping high voltage,10～20nm ultra-thin carbon foil treatment,and 30kV acceleration high voltage,have been resolved in the process of TIMS development.The prototype of TIMS has been calibrated by the calibration system in the University of Bern.The calibration results show that the performances of TIMS are as follows.The energy measurement range is from 0.499eV to 29.94keV,and the energy resolution is 10.5％.The field of view is 360° ×8.4°,and the angular resolution is 22.5°× 8.4°.The main ion species including H+,He+,O+ can be resolved.On the basis of the research work in this study,more advanced plasma instruments with higher mass resolution,larger field of view and more miniature design can be developed.

The FY2 series satellites are the principal observational platforms for covering dynamic weather events and the near-earth space environment in China. High energy particle detectors carried on the satellites have provided continuous and simultaneous monitoring of the geosynchronous energetic particle environment. The FY2G satellite is equipped with a new generation of energetic particle detectors, including two instruments for monitoring geostationary altitude incident flux density of protons, alpha particles, and electrons in more extensive and precise range of energy levels. The high energy electrons instrument senses incident flux of 200 keV to greater than 4 MeV high energy electrons with eleven channels. The high energy protons and heavy ions instrument senses incident flux of high energy protons with seven channels from 4 MeV to 300 MeV. The paper presents several representative observations performed from Jan 2015 until Oct 2015 with the new detector aboard on the FY2G satellite. A precise description and preliminary analysis of particle dynamics during disturbances such as magnetic storm, substorm, and solar eruption suggests that the detector can accurately respond to various disturbances and can provide refined particles data. Further comparison of particle dynamic observations of FY2G satellite with GOES series satellites leads us to believe that significant differences exist in particle flux evolvement. It appears that under some conditions the energetic particle fluxes can enter into a coherent level, yet intensive disturbances can cause great difference between observations of the satellites, which can be helpful for data assimilation of multi-satellite as well as further research in more complicated magnetosphere energy particle dynamics.

This article introduces a chargesensitive preamplifier used in Space Particle Detectors and analyses on some of its important parameters, such as charge sensitivity, time constant and noise characteristic, whichhave important influence on the detectors'performance index.Then we put forward some considerations on actual cir-cuit design.Finally,we design a specific circuit to testing and validation.Above all the articlecan provide some referencetoimprove the detector's performance and the practical application.

Quantum bit error rate is an important operating parameter in quantum key distribution system.Aiming at satellite to earth quantum key distribution system,an quantum bit error rate model was established with several factors,such as background light,quantum polarization degradation,polarization misalignments and photodetector dark current.Calculation formula of quantum bit error rate and sifted key bits was given,as well as the numerical simulation results for laser links between ground and a 300km altitude satellite.This study shows that,when the pulse frequency is set at 30kHz and with good weather conditions,the quantum polarization degradation is the main factor that contributes to error bit,which provides the significant instruction for the design of satellite-earth quantum key distribution system.