GFM-II Large Area Floor Alpha and Beta Pollution Monitor
GFM-II Floor Monitor
The measurement objects of the large area floor pollution monitor are alpha and beta surface contamination on the regular surfaces of nuclear power plants, nuclear decommissioning sites, nuclear fuel production sites and isotope production departments. The level of alpha and beta surface contamination can be given respectively. The probe is a flat-plate flow-air proportional counter array with a window area of 1000 cm 2 and consists of four sensitive detection areas. Each detection area is equipped with a charge sensitive preamplifier circuit, which consists of four independent detection channels.
Characteristic:
The flow-air proportional counter array replaces the single flow-air proportional counter, which has low working pressure and fast simultaneous scanning measurement technology of alpha and beta.
Main Technical Indicators
(1) Measurement timing:
3-255 s, background measurement and target ground measurement can be selected separately
(2) Threshold setting:
0~9999 cps
(3) Minimum detectable limit (environmental background 0.2 mGy/h, confidence 99%, measurement time 10 s):
β： 0.4 Bq/cm2
α： 0.04 Bq/cm2
The minimum detectable emissivity of beta is not more than 200 CPS
The minimum detectable emissivity of alpha is not more than 20 CPS
(4) alpha-beta series ratio (90Sr+90Y beta source and 239Pu alpha source):
The interference of alpha signal to beta count is not more than 20%.
The interference of beta signal to alpha count is not more than 1%.
(5) Working gas:
Argon methane: 90% Ar + 10% CH4
(6) Ping Chang:
Not less than 150 V
