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Quantum Detectors: Detectors Based on Photoelectric Method

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Quantum Detectors: Detectors Based on Photoelectric Method

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Questions and Answers

What characteristic of quantum detectors is wavelength dependent?

Quantum efficiency
Response time
Noise equivalent power
Responsivity (correct)

How is the quantum efficiency of photoemissive detectors calculated?

Dividing radiation sensitivity by wavelength
Using percentage of area covered by the detector
Multiplying current by wavelength
By dividing detector area by the radiation sensitivity (correct)

What does the Response Time of a detector indicate?

Time taken to cool down the detector
Time taken to turn on the detector
Time taken to reach maximum sensitivity
Time taken to reach 63% of its final value (correct)

What does Noise Equivalent Power (NEP) measure?

Minimum detectable power (D) Signup and view all the answers

Which type of quantum detector includes Vacuum Photodiode and Photomultipliers?

Photoemissive detectors (C) Signup and view all the answers

How is Quantum Efficiency expressed?

as a percentage (C) Signup and view all the answers

What is the maximum kinetic energy of a photoelectron ejected from a photocathode?

$(K.E)_{max} = h u - \" \phi$ (A) Signup and view all the answers

What is the relationship between Detectivity (D) and NEP?

$D = NEP^{-1}$ (B) Signup and view all the answers

What is the minimum frequency required to cause photoelectric emission?

threshold frequency ($\nu_c$) (A) Signup and view all the answers

What is the formula for normalized detectivity (D*)?

$D^* = D \cdot A^{1/2} \cdot \" \Delta f^{-1/2}$ (A) Signup and view all the answers

What is the threshold frequency for photoelectric emission in a photocathode made of alkali materials?

less than 1.2 \mu m (B) Signup and view all the answers

What is the measurement units of normalized detectivity (D*)?

cm Hz1/2/W (A) Signup and view all the answers