Gas Proportional Detector - Model 120
Specifications

INDICATED USE: alpha, beta, gamma sample counting
WINDOW: 0.4 mg/cm² metalized polyester
WINDOW AREA: active and open 32 cm² (5 in²)
SAMPLE SIZE: maximum 5.1 cm (2 in.) diameter
SAMPLE TRAY: adjustable height from 0 to 0.9 cm (0 to 0.35 in.)
CONNECTOR: series "C"
EFFICIENCY (4π): 10% for 14C; 42% for 90Sr/90Y; 35% for 230Th; less than 1% for gamma
RECOMMENDED COUNTING GAS: P-10 Mixture (10% methane, 90% argon)
SUGGESTED INSTRUMENTS: Models 12, 2200, 2221, 2241, 2241-2, 2350-1, 3030E
OPERATING VOLTAGE:
alpha: 900-1300 volts
beta gamma: 1300 to 1700 volts
COUNTER THRESHOLD SETTING: typically 2 to 5 mV
SIZE: 11.4 x 10.2 x 13.9 cm (4.5 x 4 x 5.5 in.) (H x W x L)
WEIGHT: 0.9 kg (2 lb)