Methods of Improving Non-Linearity in Photomultiplier Tubes for Radiation Detection

Radiation is a form of energy. There are many types of radiation, but this paper will only discuss one type of radiation, gamma radiation. High exposure to gamma radiation may harm living organisms; hence, it is important that a method to measure gamma exposure is developed. A common way to measure gamma radiation is by using a photomultiplier tube (PMT) with a scintillator. The scintillator converts gamma rays to visible light for the PMT. However, PMT’s can only measure low to medium amounts of light. When measuring high amounts of light, the PMT becomes non-linear, which causes accuracy problems. It is possible to tune the PMT to read high amounts of light, but then it will not be able to detect low amounts of light due to the capability of the electronics to read low amounts of quiescent current with good resolution. This research paper identifies the cause of non-linearity in PMT’s and discusses the possibility of using one PMT with a scintillator to measure low to high amounts of light by solving the non-linearity issues. This research paper will also resolve the issue of measuring low amounts of quiescent current with good resolution to improve detector accuracy. This will improve the radiation detection industry because it will be much easier to perform radiation detection with one PMT that can detect low to high amounts of light without having to tune the PMT depending on the expected light intensity. This method will also help with reducing electronics power consumption for the PMT in gamma radiation detection. These results illustrate that solving non-linearity in PMT’s and the ability to measure low amounts of quiescent current with good resolution is possible, however it will require a little more work to find the right electronic switches to obtain efficient power consumption.