Table of Contents
What is a pulse height spectrum?
A pulse-height spectrum is a display showing the number of events detected (“counts”) versus the amplitude of those events. This is provided most conveniently by a multichannel analyzer (Chapter 8, Section C.
What is a photopeak?
The photopeak refers to the region of the pulse height spectrum caused by the complete photoelectric absorption of gamma rays by the scintillator crystal of a gamma camera.
What is the importance of photomultiplier tube in a scintillation counter?
Accordingly, a scintillation counter consisting of a scintillator and a photomultiplier tube provides accurate radiation energy distribution and its dose rate by measuring the photomultiplier tube output pulse height and count rate.
What causes Compton Valley?
Compton Scattering – Compton Continuum Compton edge. They are produced when the angle of the scattered gamma ray is 180 degrees. Photons scattered at 180 degrees frequently have energies close to 200 keV. As such, the Compton edge is usually 200 keV to the left of the photopeak.
What is a PMT and why is it important?
PMT is the technology state of the art at present. The photomultiplier is an extremely sensitive light detector providing a current output proportional to light intensity. Photomultipliers are used to measure any process which directly or indirectly emits light.
How do you find the resolution of a detector?
%Energy resolution = FWHM x 100 /photo peak Energy resolution is expressed as a percent of the FWHM of a specific energy. Most cameras have an energy resolution in the range of 11% to 13% FWHM at 140 KeV.
How Compton edge is formed?
What is peak to Compton ratio?
Peak to Compton ratio (PCR) is the ratio between the height of the photopeak and that of the Compton continuum, which is defined for source of the gamma ray spectrum as the ratio between the height of the photopeak and the average height of the Compton peak [12].
What is NaI detector efficiency?
For 40K, the absolute efficiency is calculated from the photopeaks of 40K (1460.8 keV) and it is 0.013542. The Full energy peak efficiency as a function of gamma ray energy of a NaI (Tl) detector is shown in Figure 1(b).