Radiation detection systems
GPS Scintillometer
GPS Scintillometer (GPSSC)
The RDS GPS Scintillometer is a dual purpose gamma radiation monitor that measures the external gamma count rate (cps) and the external gamma dose rate (µSv/h).
When an external GPS antenna is connected, the reading number, the latitude and the longitude of the reading position and the count rate are logged into the internal memory. The distance in meters between subsequent monitoring/logging positions has to be programmed when the scintillometer is in a programming mode (the GPS resolution is approximately 3-5 m). During a survey it is possible to set an alarm count rate (cps) level by the use of 2 momentary switches.
Logged data can be downloaded into a MSWindow Hyperterminal or Putty programs as a text file that can be opened in MSExcel.
The Φ1"x 1" NaI(Tl) scintillation crystal coupled with a low noise photomultiplier tube (PMT) is the gamma detector system adopted by the RDS GPS Scintillometer. The high voltage power supply/preamplifier/amplifier board pre-amplifies and amplifies gamma pulses that are counted and processed by the microcontroller board coupled with the two line LCD board.
The gamma count rate (cps) is displayed every second. An alarm function is supported by an internal buzzer. The alarm value (cps) can be changed any time when the scintillometer is used by an UP (U) or DOWN (D) momentary switch.
The scintillation crystal and the PMT are housed inside a metal cylinder that is situated in the front bottom right hand side corner of the enclosure (when the belt clip faces the body).
The displayed external gamma dose rate (µSv/h) is calculated by multiplying the count rate by the calibration constants P1 (P1=0.00436). The calibration constant was established through the calibration of the RDS Scintillometer in a gamma radiation field of the 137Cs calibration rig of the SA EPA’s Radiation Protection Division.