HIGH PERFORMANCE TRITIUM IN AIR
PORTABLE SURVEY MONITOR
The 400SBDγC is useful for measurements as low as 2 μCi/m3 . The new OTC electrometer, which measures to below 10-16 amperes combines low noise and high zero stability. Unlike other instruments, the 400 series instruments no longer require a front panel manual zero control. Thermally induced zero shifts of the electrometer and associated electronics have been eliminated.
RADON INTERFERENCE, NOISE RESPONSE
For an unambiguous measurement of very low tritium a monitor must be able to ignore response to ambient radon. The 400SB series incorporates this capability and therefore produces accurate, fast and drift free
measurements to nearly +1 μCi/m3.
TOTAL GAMMA COMPENSATION
Cruciform ionization chamber geometry provides nearly perfect gamma compensation regardless of photon energy, flux gradient or flux direction. Gamma compensation of the 400 series instruments is typically three orders of magnitude better than instruments using nested or side by side ionization chambers.
Its exceptionally rapid response is uniquely due to its abiltiy to ignore radon. The electronic time constant is only 10 seconds, the pneumatic time constant of about 12 seconds, for an overall time constant of only 15 seconds. Meter readings will reach 90 % of final value within 30 seconds to a step response of aspirated tritium.
FAST WARM UP, NO ZERO DRIFT
After applying power, the initial transient “warm up” drift effects take less than a minute. Long term drifts have
been eliminated, manual zero adjustments are no longer required.
By addition of a desiccant column, this survey instrument will specifically measure HTO in the presence of other
radioactive gases as well as background gamma. The desiccant can be regenerated repeatedly for reuse.