Cremat's CR-113 is a single channel charge sensitive preamplifier module intended for use with various types of radiation detectors. The CR-113 is one of a series of four charge sensitive preamplifiers offered by Cremat, which differ from each other most notably by their gain. A guide to selecting the best charge sensitive preamplifier for your application can be found at our web site. As with all Cremat's preamplifier modules, the CR-113 is small (less than one square inch in area), allowing for compact multichannel detection systems to be constructed using a modular design.
The CR-113 can be used either in a direct coupled (DC) mode, or an AC coupled mode. If the detector current exceeds 30 uA, it is recommended that an AC coupled mode be used to prevent the resulting DC offset of the preamplifier output from saturating. Low frequency detector current (e.g. 'dark' current, or leakage current) produces an offset in the preamplifier output voltage at a rate of 70 mV per A. The use of AC coupling also is useful in improving the counting rate capability of the preamplifier. For further discussion of this topic and a schematic diagram of an AC-coupled detection circuit utiltizing the CR-113, see the specification sheet for the CR-150-AC evaluation board at CR-150.pdf .
The CR-113 circuit is contacted via an 8-pin SIP connection (0.100" spacing). Leads are 0.020 inches wide. Pin 1 is marked with a white dot for identification.
Equivalent circuit diagram
Figure 2 above shows a simplified equivalent circuit diagram of the CR-113, which is a single stage amplifier. Pin numbers corresponding with the CR-113 preamplifier are shown. Rf (68 k Ohm) and Cf (750 pF) are the feedback resistor and capacitor respectively.