A germanium detector absorbs a gamma ray from in a single photoelectric interaction

PHYSICS · Multi-part · Fermi University Physics · Nuclear Physics · Electronics, Instrumentation & Communication · Radiation interactions, detection and dosimetry

The Nucleus Resolved, Ch From a pulse to a number: detectors, resolution and what a spectrum establishes

Problem

A germanium detector absorbs a

122\,\mathrm{keV}

gamma ray from

^{57}\mathrm{Co}

in a single photoelectric interaction. The mean energy to create one electron-hole pair in germanium is

W_{\rm ion} = 2.96\,\mathrm{eV}

and the measured Fano factor is

F_{\rm Fano} = 0.08

. ((a)) Calculate the mean number of carriers produced,

\bar N

. ((b)) Calculate the Fano-limited energy resolution, expressed as the FWHM in

\mathrm{keV}

, using

\Gamma_{\rm stat} = 2.355\sqrt{F_{\rm Fano}W_{\rm ion}E}

Related theory

Nuclear Physics

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