Model FF-26 and FF-27 Flat Feret Tritium Detectors

The FF-26 and FF-27 Tritium Contamination Monitors are portable gas flow proportional counters sensitive to betas of H-3. The windowless probes easily glide over flat surfaces on poly tape which provides some spacing from surface as well as easy scratch-free movement. The poly tape is easily cleaned but may also be replaced if contaminated. P-10 and P-5 counting gas utilized in these tritium monitors is non-combustible and can be used in any environment.
Gas use is minimized due to the efficient design of chamber and by an automatic-shutoff valve when the ``trigger'' on probe handle is released. Typical counting efficiency is 50% 2 pi of all Tritium betas escaping the surface.  Results  were compared using an internal hemispherical 2 pi counter. Gas flow is normally set at 800 cc/min, giving a one hour use for lecture bottle or, of course, proportionally longer within larger cylinder. (See option below) Probe may also be used to monitor hands, clothing and equipment with included Model H face plate. Two lecture cylinders for P-10 gas are included with instrument. * cylinders are shipped empty when shipped.

 The electronics include stabilized high voltage bias supply, preamp, pulse shaper and pulse to analog converter. Circuit design minimizes recovery time of detector and allows linear response at higher count rates than previously possible. A piezo electric speaker with volume control and 3-1/2'' meter provide audible as well as visual readout.

Model FF-27 is effective in rejection of other nuclides and integration capabilities.

Tritium Surface Contamination Monitor
Model # FF-27 Specifications:

•Low Gas Consumption
•Built-in Audio
•Auto Gas Shut-off

500; 5,000; 50k; 500k cts/min (PTS-26M and PTS-27M) or
0-10; 100; 1,000; 10,000 cts/sec (PTS-26S and PTS-27S)
•Flowmeter: 10-1000 cc/min. Needle valve control.
•Background: Typically less than 500 cts/min or 10 cts/sec (PTS-
26M or PTS-26S)
800 cts/min for (PTS-27M)
15 cts/sec for (PTS-27S)
Open range switch, battery check, flow gas control, sound volume
Hidden high voltage bias supply for detector: Input sensitivity high
voltage control.
•Calibration: 4 range pots and 1 overall control. Internal.
•Detection Area:
PTS-26S (or M) With clothing mask attached 0.5cm x 6.5cm. Mask
removed 1.5cm x 11.5cm.
PTS-27S (or M) With clothing mask attached 0.5cm x 14cm. Mask
removed 4.6cm x 21.6cm.
At 100 Bq/100 cm2, 35 cts/sec above background for PTS-27.
6 cts/sec above background for PTS-26.
•Battery: 2 nine volt ``transistor'' batteries Eveready 1222 or
equivalent, 300 hour normal operating life.
Probe PTS-26: 0.53 Kg (1lb. 3 oz.)
Probe PTS-27: 0.57 Kg (1lb. 4 oz.)
Electronics Package: 2.6 Kg (5lbs. 12oz.) plus
P-10 gas container: 0.6 Kg (2lbs. 6 oz.)
•Shipping Weight: 15 lbs.
•Option: Larger gas cylinder (DOT 3AA2015)35 capacity of lecture
bottle. On two wheel dolly.

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