Thermo 1220 Hot Spot Monitor

(Product Number 1220 Hot Spot)

The Model 1220 is a portable, dual-detector telescoping dose ratemeter intended for monitoring rates up to 1.0 Svh-1.

This instrument utilizes a telescoping probe employing two G-M tubes, one gamma compensated (GM1) and one uncompensated (GM2). The compensated tube measures ambient dose equivalent H*10 with a useful energy range of 50 KeV to 1.25 MeV. The uncompensated tube has a similar range for gamma radiation but also responds to beta radiation for EMax energies of >0.5 MeV. The monitor is therefore useful for distinguishing the amount of penetrating versus non-penetrating radiation that emanates from a particular source. The effective dose rate range is 150 µSv/h to 1.0 Sv/h.

To ensure operator safety, the detector assembly is mounted on a robust, light-alloy extrusion that can be extended from 1m to 2m. The assembly can be set into intermediate positions by means of a locking collar. For remote siting, the head can be detached from the ratemeter and re-connected via a 30m extension cable.

An analog meter registers the count rate on a semi-logarithmic scale, thus making range changing unnecessary. An audio/visual warning alarm indicates fault conditions such as GM tube failure and low battery.

Power is provided by two 'C' size cells mounted in the ratemeter handle.

Specifications:
Radiation Detected: GM1 Gamma + Beta
       GM2 Gamma only
Energy Response GM1: Gamma 50 KeV to 1.25 MeV uncompensated Beta >0.5 MeV
Energy Response GM2: Gamma 50 KeV to 1.25 MeV +20% relative to 137Cs
       No significant Beta response
Rate Range: Single 150 uSv/h to 1.0 Sv/h (15mR/n to 100 R/h)
Battery Data: Style - 2 "C" cells type LR14 (alkaline manganese)
Life - Minimum of 50 hours continuous use
       II V Supply: DC - 600 volts +10% at maximum current 200 microamps
Response Time: 0.1 - 10 mSv/h less than 5 seconds
       10 - 1,000 mSv/h/ less than 2.5 seconds
Linearity: 0.1 - 10 mSv/h +15% (15 - 200 counts/s)
       10 - 1,000 mSv/h +10% (200 - 30,000 counts/s)
Meter: Type - long scale (270 degrees); f.s.d. analog meter
Scale - Semi-log 0.1 - 1,000 mSv/h
Ambient : -20 to 40oC (-4 to 104oF)
Relative Humidity : 95% at 35oC (95oF (non condensing)
Case Size: Closed - 100 mm x 90 mm x 1,780 mm (inc. probe)
       Extended - 110 mm x 90 mm x 2,650 mm (inc. probe)
Probe Size: 180 mm long x 40 mm diameter (7" long x 1.5" diameter)
       (Optional 30 meter (97 foot) cable is available to remotely site probe unit)
Total Weight: 2.7 kg (6 lbs)