Radiation Detector Readout System for Space Borne Instrumentation

A space-borne instrument is an instrument has to survive very hostile space environment. The cost of launch is determined by the payload's weight. In that regard, it is necessary to have the least amount of mass, power, and size instrument onboard in order to complete tasks with the best possible performance. Any instrument onboard a spacecraft is likely to be exposed to harsh radiation, extreme temperature swings, and high vacuum conditions. The instrument should also be able to withstand launch vehicle vibration. At various levels of the instrument design, such as selecting components/devices with space qualification, desired radiation testing, design, and packaging of the instrument, care must be taken for the above-mentioned aspects. Instruments built with Commercial-Off-The-Shelf (COTS) components will not withstand the harsh space environment and satellite launch loads. For these reasons, "space instruments are custom-designed one-of-a-kind instruments, and the construction of such a one-of-a-kind instrument is dependent on the mission and the instrument configuration required for the scientific application".

Radiation detectors are widely used for measuring radiation emitted by various space objects in the X-ray, Gamma-ray, or high-energy particle regions of the spectrum. Ionizing and non-ionizing radiation are the two main types of radiation. Non-ionizing radiation from ultraviolet is less energetic. The atoms and molecules that interact with UV light particles receive energy from them but do remove their electrons. There are several types of ionizing radiation, including galactic cosmic radiation, trapped radiation, and solar energetic particles. The Galactic cosmic radiation is emitted as massive clouds of high-energy charged particles believed to be emitted by supernovas. The earth's magnetic field is strong enough to catch the charge particles and, in the field, these particles travel in a spiral pattern. Solar particle events involve the Sun releasing energetic solar particles. Sudden, powerful storms may develop as a result of this.

Radiation detector instruments usually have a similar kind of readout method which contains CSPA, Shaping amplifier and pulse height analyzer. A suitable pulse height analyzer is required based on instrument specifications such as energy resolution, count rate, mass, etc.

There are currently no commercially available back-end electronics to read these many channels. The reading approaches that are currently available demand more mass, power, and processing. The development of a new pulse height analysis technique for spaceborne instruments is required in this direction. The technique should provide comparable or better performance while using less instrument mass, power, and size.