A becquerel (Bq) is equivalent to one disintegration per second.
Appendix A - Technical Specifications
Detector: Internal Halogen-quenched Geiger-Mueller tube. Effective dia. 1.75” (45 mm). Mica window density 1.5-
2.0 mg/cm2.
External RAP-RS1 Same detector as internal. Anodized aluminum Inspector EXP+ only housing with black vinyl
grip. 500 volt power supply is located in the probe head.
Connectors: Amphenol 31226 twinax.
Display: 4-Digit liquid crystal display including mode indicators
Operating Range: mR/hr: .001 to 100.0
CPM: 0 to 350,000
Total: 1 to 9,999,000 counts
µSv/hr: .01 to 1000
CPS: 0 to 5,000
Efficiency: Sr(Y)-90: approx. 38%; C-14: approx. 5.3%
4 p at contact P-32: approx 33%; Co-57: approx. .3%
Gamma Sensitivity: 3340 CPM/mR/hr referenced to Cs-137
Smallest detectable level for I-125 is .02 µCi at contact
Averaging Periods: Display updates every 3 seconds, showing the average for the past 30-second time period at
normal levels. The averaging period decreases as the radiation level increases. Refer to
Chapter 3 Operation- Autoranging, Display update.
CAL Factor Range: 001 to 199
Timer: Can set 1-10 minute sampling periods in one minute increments, 10-50 minute sampling
periods in 10-minute increments, and 1-24 hour sampling periods in 1-hour increments
Alert Range: mR/hr: 0 to 50 CPM: 0 to 160,000
Accuracy: ± 15%
Beeper: Operational in Audio mode only
Anti-Saturation: Readout holds at full scale in fields up to 100 times the maximum reading.
Temperature Range: -10° to +50° C , 14° to 122° F
Power: One 9-volt alkaline battery. Battery life is minimum 2160 hrs at normal background. Minimum
battery life is 625 hrs at 1 mR/hr.
Size: 150 x 80 x 30 mm (5.9” x 3.2” x 1.2”)
Weight: Inspector
+
327.4 grams (11.55 oz) including battery
Inspector EXP
+
610.7 grams (21.54 oz)
Appendix B Sensitivity to Common Isotopes
Typical GM tube efficiency for 4 Pi geometry at contact
Isotope E max. MeV Efficiency
Beta
14
C 49 keV Avg. 156 keV Max. 5.3%
210
Bi 390 keV Avg. 1.2 MeV Max. 32%
90
Sr(Y) 546 keV and 2.3 MeV 38%
32
P 693 keV Avg. 1.7 MeV max. 33%
Alpha
241
Am 5.5 MeV 18%
Energy Sensitivity:
Detects Alpha down to 2 MeV.Detects Beta down to .16 MeV; typical detection efficiency at 1 MeV is approx. 25%.
Detects Gamma down to 10 KeV trough the end window