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As an example, we have considered datasheets of 2 sensors. Those are DT Standard Photodiode Products [7] and First Sensor PIN PD [8].
Although It is impossible to set the exact mathematical equation to introduce the transfer function of the sensors (nor do the datasheets give any transfer functions), it can be defined after measuring and analyzing spectrum. Radiation detectors are usually very high sensitive, though the exact value is not defined. It can be improved by depressing noise signals which appear from e.g. light. Manufacturing material's quality is very important in sensitivity rise.
Although It is impossible to set the exact mathematical equation to introduce the transfer function of the sensors (nor do the datasheets give any transfer functions), it can be defined after measuring and analyzing spectrum.The maximum efficiency for both sensors is achieved at 10 keV energy level (Figure 3, Figure4).
Figure 3. X-ray Efficiency vs. Energy in XRB series Diodes. Reprinted from http://www.deetee.com [7].
Figure 4. Absorption of gamma radiation. Reprinted from http://www.marubun.co.jp [8].
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