1 Chapter No. 17 Radiation Detection and Measurements, Glenn T. Knoll, Third edition (2000), John Willey. Measurement of Timing Properties

3  A) Timing Spectroscopy-Walk Optimization of CFD  Identify the equipment such as detector, electronics modules and NIM bin.  Note down detector type, size, operating voltage and its polarity.  Read the manuals of NIM modules particularly input requirements and output specifications and its principle of operations.  Connect the circuit diagram as shown in Figure. Ensure that the detector power supply has the same polarity as the detector voltage polarity, otherwise change the polarity on the power supply.  Connect the detector anode out put to an oscilloscope.  Switch on the detector power supply and apply the detector voltage.  Now place a gamma ray source near the detector. Observe the anode signal on the oscilloscope.  Note the rise time of the anode pulse.  Connect the anode pulse to the input of the CFD. Select CFD mode on the CFD.  Connect a delay cable corresponding to 40-90% of rise time in the delay connection of the CFD.  Connect the walk inspect signal of the CFD as per attached diagram to the oscilloscope.  Adjust the walk according to Figure (b) using potentiometer on CFD

4 A) Optimization of Walk of the CFD  Measure the detector anode pulse rise time on the oscilloscope.  Connect the anode output of the detector to input of the CFD.  Select CFD mode of the CFD and connect to the input of the MCA.  Select a delay cable for a delay corresponding to 40-90% rise time of the anode signal.  Connect the walk inspect output of the CFD to the oscilloscope as per attached circuit  Adjust the walk switch to bring the walk pattern similar to figure (b) shown below.

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