Eberline HP-210L. Lead shielded GM that allows for use in high radiation backgrounds.
From UMASS Lowell Web site:
Eberline Model HP-210 Pancake G-M
The Model HP-210 series hand probes provide a sensitive beta detector featuring a "Pancake"GM tube with a thin mica window. The open window, which is protected by an etched stainless steel screen, permits useful beta sensitivities down to 40 keV. The detector is alpha sensitive (above 3 MeV).The HP-210 is designed for contamination surveys on personnel, table tops, floors, equipment, etc. The HP-210T, with a high density tungsten shield, permits relatively low-level beta monitoring in a gamma background. Also available is the HP-210L with a lead shield which has the same specifications as the tungsten shield. When low-level beta monitoring is required in a low background area, the HP-210AL with an aluminum housing maybe used.
Indicated Use: Alpha beta gamma survey; Frisking
Detector: Pancake type halogen quenched G-M
Window: 1.4 to 2.0 mg/cm² mica
Window Size: 4.45 cm diameter (1.75”); 15.5 cm2(2.4 in2)
*Efficiency (BETA): Typically With Screen Cs-137 = 22%; Co-60 = 16%; SrY-90 = 32%; Tc-99 = 15%; C-14 = 6%; Without Screen Cs-137 = 33%; Co-60 = 22%; SrY-90 = 37%; Tc-99 = 20%; C-14 = 9%
Shielding Ratio Co-60=4:1, HP-210T, HP-210L (window: back); Co-60=1:1, HP-210AL
Sensitivity: Alpha- 3 MeV at window; Beta- down to 40 keV
Dead Time: Typically 50 microseconds max
Compatible Instruments: General purpose survey meters, ratemeters, and scalers
Operating Voltage: Typically 900 ± 50 volts
Connector: BNC Series Coaxial
Series Resistor: 3.3 MΩ (in probe)
Ttemperature Range: -30 °C to 75 °C (-22 °F to 167°F)
Size: 16.5 cm x 8.9 cm x 9.7 cm (6.5” L x 3.5” W x 3.8” H)
Weight: 1.9 kg (4.25 lb) HP-210T, HP-210L;0.7 kg (1.5 lb) HP-210AL
*Efficiencies listed as percentage of 4π emission rate, from a 2” diameter circular area of a 10cm2 square source for Cs-137 and Co-60 sources. Efficiencies listed as percentage of 4π emission rate, from a 1.75 diameter source for other isotopes. Open area of the etched stainless steel screen is 79%.