Physics and Engineering of Radiation Detection

648 Chapter 11. Dosimetry and Radiation Protection

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Electrode

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Quartz Fiber

Radiation

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Ionization Chamber

Ionization Chamber

Reading Pointer

Figure 11.4.5: (a) Quartz fiber electroscope without any absorbed

dose. (b) Incident radiation produces charge pairs in the ionization

chamber that decreases the charge on the electrometer pushing the

electrodes close together. The eyepiece of the microscope is shown to

read a dose of 140 units.

Easy Handling:This device is of the size of a pen and can be carried in a

pocket. Its outer metallic surface makes it sturdy against mechanical shocks

and therefore it does not require any special handling requirements.

Quartz fiber electroscope also suffers from some disadvantages, some of which are
listed below.

Readout Errors: The readout scale of the electrometer is fairly narrow and

can not be very accurately read out. The readout process is also prone to

human errors.

Low Dynamic Range:The very small volume of the ionization chamber does

not allow accumulation of large doses and, in hostile radiation environments,

the instrument gets saturated fairly quickly.

Low Accuracy:The accuracy of the instrument is lower than other types of

dosimeters, which does not make it suitable for accurate dose measurements.