Physics and Engineering of Radiation Detection

376 Chapter 6. Scintillation Detectors and Photodetectors Incident Photons Electrons Photocathode Vacuumed Glass Enclosure Dynod ...

6.5. Photodetectors 377 Incident Photons Photocathode Dynode Chain Focusing Structure Vacuumed Glass Enclosure Anode Electrons F ...

378 Chapter 6. Scintillation Detectors and Photodetectors Incident Photocathode Photons Anodes V acuume d^ Gl ass E nc losure Fi ...

6.5. Photodetectors 379 A.4 VoltageDividerCircuit Proper focusing and acceleration of electrons at each stage of multiplication ...

380 Chapter 6. Scintillation Detectors and Photodetectors important factor to consider is that the geometry of the last dynode a ...

6.5. Photodetectors 381 Rn−1 Rl Rn Vout Cs Anode +HV C Figure 6.5.13: Typical output circuit of a PMT. The anode current is conv ...

382 Chapter 6. Scintillation Detectors and Photodetectors Wavelength ( )nm 100 200 2000 0 50 100 Transm iss ion (%) Figure 6.5.1 ...

6.5. Photodetectors 383 of the incident photons. This implies that the quantum efficiency is also essentially dependent on the w ...

384 Chapter 6. Scintillation Detectors and Photodetectors A.9 Sensitivity............................ Just like efficiency, sens ...

6.5. Photodetectors 385 whereNγrepresents the number of photons having wavelengthλ. Substituting the expressions forIpeandPin eq ...

386 Chapter 6. Scintillation Detectors and Photodetectors Anode Luminous Sensitivity The definition of anode luminous sensitivit ...

6.5. Photodetectors 387 gainμcan be written as μ = δn = [ AVdyα ]n = An [ V n+1 ]αn = An (n+1)αn Vαn. (6.5.16) HereV is the supp ...

388 Chapter 6. Scintillation Detectors and Photodetectors whereδidenotes the gain of theith dynode and ∏ stands for the product. ...

6.5. Photodetectors 389 Dynodes 345678910 μ 103 104 105 106 Figure 6.5.17: Dependence of gain on the number of dynodes in the mu ...

390 Chapter 6. Scintillation Detectors and Photodetectors 0 50 100 −h 0 +h (a) Side−on Type PMT Head−on Type PMT 0 100 50 −r 0 + ...

6.5. Photodetectors 391 Imax 0.9Imax 0.1Imax Photon Pulse Anode Pulse Transit Time Rise Time Decay Time Time Pu lse H ei gh t Fi ...

392 Chapter 6. Scintillation Detectors and Photodetectors effective resistance seen by the output signal will actually be 1 Rl,e ...

6.5. Photodetectors 393 A.14EnergyResolution The pulse height at the anode of a PMT depends on the number of secondary electrons ...

394 Chapter 6. Scintillation Detectors and Photodetectors anode at all. It is therefore very important that, specially for measu ...

6.5. Photodetectors 395 I 2 I 1 I 2 I 1 Time (a) Number of Pulses Incident Photon Emitted Photoelectron (b) Pulse Height > Ou ...