Energy Resolution Of Semiconductor Detectors Research Articles

Theoretical Approach to Energy Resolution of Semiconductor Detectors

All processes occurring in semiconductor detectors during detection of primary monoenergetic particles lead to broadening of spectral lines. In this work, a general expression for the energy resolution of semiconductor detectors is obtained using the theory of branching cascade processes. It is shown that the general formula involves all contributions to the spectral line broadening described in the literature and additional contributions associated with fluctuations of electron and hole lifetimes caused by inhomogeneity of traps in the semiconductor material and fluctuations of the electronic channel gain.

Evaluation of scintillators and semiconductor detectors to image three-photon positron annihilation for positron emission tomography

Positron emission tomography (PET) is rapidly becoming the main nuclear imaging modality of the present century. The future of PET instrumentation relies on semiconductor detectors because of their excellent characteristics. Three-photon positron annihilation has been recently investigated as a novel imaging modality, which demands the crucial high energy resolution of semiconductor detector. In this work the evaluation of the NaI(Tl) scintillator and HPGe and CdZTe semiconductor detectors, to construct a simple three-photon positron annihilation scanner has been explored. The effect of detector and scanner size on spatial resolution (FWHM) is discussed. The characteristics: energy resolution versus count rate and point-spread function of the three-photon positron annihilation image profile from triple coincidence measurements were investigated.

Low-noise electronics for semiconductor detectors

Abstract A possible way to attain the best energy resolution of semiconductor detectors is discussed in this report. It is carried out through the matching of detector parameters and parameters of field-effect transistors (FET) of input stages in charge-sensitive preamplifiers (CSP). Four types of low-noise FETs for detectors of various capacitance are presented, the noise response of transistors is discussed. Thin films low-noise feedback resistors with nominals of 10 6 to 10 15 Ω are developed. The energy resolution of various detectors with low-noise electronics is presented.

A time-of-flight spectrometer for unslowed fission fragments

The one-armed time-of-flight spectrometer mounted in a vertical experimental port of the research reactor at the Moscow Engineering Physics Institute (MEPhI) was designed for measuring mass-energy distributions of unslowed fission fragments. The study of rare fission modes in the yield regions up to 10 −6 is carried out having a target location near the reactor core and an electrostatic particle guide system installed, which increases the efficiency ratio of the spectrometer by a factor of 50. The special “heavy ion generator” operation mode of the spectrometer can be used for studies of fast (∼ MeV/amu) heavy ion interaction with matter. The fission fragment energy is measured by an ionization chamber or a semiconductor detector. The negligible angular divergence of the fragment beam enables fission fragment detection in a channeling registration mode to improve the energy resolution of semiconductor detectors. The fragment velocity is determined by the time of flight between two time pick-off microchannel plate detectors. A new procedure using unseparated fission fragments was developed to obtain the correct value for the time resolution of the system.

Effect produced by the charge collection time upon the time and energy resolution of semiconductor detectors

The effect produced by the charge collection time upon the time and energy resolution of semiconductor detectors has been studied. It is shown that sampling of pulse rise times permits one to identify in coaxial detectors a group of pulses corresponding to the detection of radiation in surface layers of the detector. Choosing pulses with the maximum rise time rate allows one to improve the time resolution of the coincidence spectrometer and achieve 2 τ = 1.65 ns, instead of the 2 τ = 5.50 ns for coincidences of the 1332 keV gamma line and β − particles from 60Co.