Physics and Engineering of Radiation Detection

708 Chapter 12. Radiation Spectroscopy

Beam−Stop

Assembly

Time−of−Flight

Detectors

Sample

Beam Monitor

Neutrons

Choppers

Collimator

Argon−Filled

Chamber

Neutron Guide

Figure 12.3.5: Principle design of a disk chopper spectrometer.

B.5 FermiChopperSpectrometer(FCS)

A Fermi chopper spectrometer is similar to the disk chopper spectrometer except
that it uses a suitable crystal to produce monochromatic beam of neutrons. The
monochromator is followed by a chopper assembly to create neutron bursts as in teh
case of DCS. The conceptual design of a Fermi chopper spectrometer is shown in
Fig.12.3.6.

Beam−Stop

Assembly

Time−of−Flight

Detectors

Sample

Collimator

Argon−Filled

Chamber

Choppers

Neutrons

Monochromator

Assembly

Neutron Guide

Figure 12.3.6: Principle design of a Fermi chopper spectrometer.