Scintillation Incoming Detector Gammaray and Scintillation Crystal Photomultiplier tube Gammaray absorbed light emitted focus ring electrode photoelectron trajectory Phot multipliers detect light photocathode first dyno Radiation
Ionizing Radiation 11 Scintillation Detector and Photomultiplier tube
The output pulses from a scintillation counter are proportional to the energy of the radiation Electronic devices have been built not only to detect the pulses, but also to measure the pulse heights The measurements enable us to plot the intensity (number of pulses) versus energy(pu lse heigl ght) yielding a spectrum of the source
The output pulses from a scintillation counter are proportional to the energy of the radiation. Electronic devices have been built not only to detect the pulses, but also to measure the pulse heights. The measurements enable us to plot the intensity (number of pulses) versus energy (pulse height), yielding a spectrum of the source
Gamma ray spectrum of 0/mpb(half-life 0.806 sec) y-ray 207mPb Decay Scheme spectrum 1633.4keⅤ of 207mpb Intensity (log scale) 1063 1e4 569 569.7kev 1063 1e3 569 0. 0 stable 1e2 569+1063 Energ
Ionizing Radiation 13 Gamma ray spectrum of 207mPb (half-life 0.806 sec) 207mPb Decay Scheme 13/2+____________1633.4 keV - Intensity (log scale) 1063 -1e4 569 5 /2 -____________569.7 keV 1063 -1e3 569 1 /2 -____________0.0 stable -1e2 -10 569 + 1063 -1 Energy -ray spectrum of 207mPb
Fluorescence Screens Fluorescence materials absorb invisible energy and the energy excites the electron De-exciting of these electrons results in the emission of visible light. J.J. Thomson used fluorescence screens to see electron tracks in cathode ray tubes Electrons strike fluorescence screens on computer monitors and Tv sets give dots of visible light Rontgen saw the shadow of his skeleton on fluorescence screens Rutherford observed alpha particle on scintillation material Zinc sulfide Fluorescence screens are used to photograph X-ray images using films sensitive visible light
14 Fluorescence Screens Fluorescence materials absorb invisible energy and the energy excites the electron. De-exciting of these electrons results in the emission of visible light. J.J. Thomson used fluorescence screens to see electron tracks in cathode ray tubes. Electrons strike fluorescence screens on computer monitors and TV sets give dots of visible light. Rö ntgen saw the shadow of his skeleton on fluorescence screens. Rutherford observed alpha particle on scintillation material zinc sulfide. Fluorescence screens are used to photograph X-ray images using films sensitive visible light
Decay Material constant Primary applications Comments ns Inorganic: NaI(TI) 230 (1)x-and y-ray detectors (1) hygroscopic (2)x-and y-ray (2)high Z material spectrometers 3)33 inch most common for y (4)y-ray resolution of 6-8% (5)right cylindrical shape most common (6) well-type have outstanding efficiency Organic BC-400 (1)x-and y-ray detectors (1) non-hydroscopic NE-102 (2)used in portal and large(2) inexpensive plastie C surface area detectors 3 low Z; minimal photoelectric effect (3)a, B and fast n detectors (4) high efficiency for charge particles (4)6 spectrometers (5) available in many sizes and shapes Common scintillation materials
Common scintillation materials