Calibration: Perform the following procedure at three-month intervals: 1. Inspect and clean or repair the probe as necessary. 2. Set PHA-Gross switch to PHA and Speaker to ON. Set Threshold at 2.50 and Window to 1.00. Using a "hot" 241Am source, adjust the HV for maximum noise from the speaker. The 60 keV 241Am peak is now centered over the 3.0 channel. Set Threshold to 1.00 and PHA-Gross switch to Gross. Position the probe at the 0.1 mR/h distance on the calibration range. Using the i-minute sealer, measure the detected counts. Divide 100 by the measured counts. The results is the calibration factor for .R/h. Input the calibration factor into the range multiplier board. Turn on decimal point (D.P.) 2. Position the probe at the 1.0 mR/h distance. The PRS-1 must indicate 1000.00 + 20%. 9. List the calibration factor on the calibration label. PG-2 and FIDLER General: The PG-2 and FIDLER are used to detect low energy gamma rays and X-rays associated with 24lam and 239py. The PG-2 detector is a thin (2mm) Nal(Tl) erystal coupled with a two-inch diameter PM tube. The FIDLER detector is a thin Nal(Tl) erystal coupled with a five-inch diameter PM tube. Calibration: The PG-2 and FIDLER are set up to search the 60 + 10 keV energy band. Perform the following procedure at three-monthintervals: 1. Inspect and clean or repair the probe as necessary. 2. Set the PHA-Gross switch to PHA, the Threshold to 5.80 and window to 0.40. 3. Using a "hot" 24l1Am source, adjust the HV for maximum noise from the speaker. The 60 keV gamma rayis now centered over the 6.0 channel on the PRS-1. If maximum noise cannot be reached in Step 3 with the FIDLER probe, then use the following alternate procedure: a. Inspect and clean or repair the probe as necessary. b. Set the PHA-Gross switch to PHA, the Threshold to 1.9, and Window to 0.2. ce. Using a "hot" 24l1Am source, adjust the HV for maximum noise from the speaker, The 60 keV gamma ray is now centered over the 2.0 channel on the PRS-1. A-29-6