Physics and Engineering of Radiation Detection

356 Chapter 6. Scintillation Detectors and Photodetectors Table 6.3.1: Densityρ, wavelength of maximum emissionλmax, decay timeτ ...

6.3. Inorganic Scintillators 357 C.2 Sodium Doped Cesium Iodide (CsI:Na)........... CsI:Nais also one of the most commonly used ...

358 Chapter 6. Scintillation Detectors and Photodetectors C.5 Cadmium Tungstate (CWO) CdWO 4 or simplyCWOis not as widely used a ...

6.3. Inorganic Scintillators 359
chemically stability,
high mechanical stability, and
temperature stability. Because of its m ...

360 Chapter 6. Scintillation Detectors and Photodetectors few parts per million level can substantially reduce its transparency ...

6.4. Transfer of Scintillation Photons 361 The simplest way to do this is to directly attach a scintillator to a photodetector h ...

362 Chapter 6. Scintillation Detectors and Photodetectors highly smooth and polished (see Fig.6.4.1). The photons that travel st ...

6.4. Transfer of Scintillation Photons 363 For the generally used light guides havingn≈ 1 .5 for visible light, this gives θi≥ 4 ...

364 Chapter 6. Scintillation Detectors and Photodetectors Radiation Incident θt θi θr Scintillation Photons θp θt θp θr (Since ) ...

6.4. Transfer of Scintillation Photons 365 Determine the minimum tapering angle of the light guide if the maximum angle of light ...

366 Chapter 6. Scintillation Detectors and Photodetectors the outer surface of the fish-tail light guide as shown in Fig.6.4.3(b ...

6.5. Photodetectors 367 Both of these detector types have their own pros and cons. for example photo- multiplier tubes have sens ...

368 Chapter 6. Scintillation Detectors and Photodetectors Dynode Vacuumed Enclosure Photons Photocathode Electrons 1R 1R 1R 1R 1 ...

6.5. Photodetectors 369 energy. Hence we have 0= hc λmax −Φ ⇒λmax = hc Φ = ( 6. 63 × 10 −^34 )( 2. 99 × 108 ) 2 × 1. 602 × 10 −^ ...

370 Chapter 6. Scintillation Detectors and Photodetectors Example: A photocathode produces a current of 20 nAwhen exposed to lig ...

6.5. Photodetectors 371 Wavelength ( )nm 200 300 400 500 600 700 800 10 20 30 QE (%) Figure 6.5.2: Quantum ef- ficiency of a typ ...

372 Chapter 6. Scintillation Detectors and Photodetectors A host of photocathode materials have been identified with varying cha ...

6.5. Photodetectors 373 electron focusing structure to guide the photoelectrons to the dynode. The reason is that the photoelect ...

374 Chapter 6. Scintillation Detectors and Photodetectors Example: ANaIscintillator is bombarded by ionizing radiation that resu ...

6.5. Photodetectors 375 issues the performance of a PMT is susceptible to mechanical jitters, which may lower the ability of one ...