Portable H3 monitors

[RadTrashMan]

Looking for a hand held, field portable Tritium (H3)air monitor.  We are sampling air in closed trailers and confined spaces.  Anything has to be better than the 15 lbs T-111 boat anchor we're using now...

[Rain Man]

Femto-Tech in Carlisle, OH makes a portable unit (can't remember the model #).  Runs on internal batteries and external AC.  Has an alarm set point, digital readout in uCi but is about only good for indication of H3.  Overhoff (location unknown) makes a unit (can't remember the model #..darned oldtimers disease) which is better than the Femto-Tech almost all the same bells and whistles but has analog readout which makes for a more stable read out (remember the RO4s??).  It weighs a ton.  Any RCT at Mound Laboratories can give you information.  They use both units.

[Nuclear_Dog]

We use 2 differant units up here.
Scintrex 209C/E/L/M which is digital but not to accurate at lower levels and the Overhoff 400 which is also digital and quite accurate at all levels. They both are effected by gamma, with gamma compensation going out the window above 5mr/h.
We also use a passive sample vial that is opened and hung in the environment you want sampled, these things are really accurate, but it usually takes awhile to get the results back from the lab (those boys don't always move to quick )

[CRUSTYJWH]

Femtotech will peg out at about 50K mci/m3, it will let ya know when to be moving out of the area.  Not good for STP's it's run with a pre-filter on it so all you should get is the gas concentration.  If ya need STP (Stable tritiated particulates) you have to go to a Fluoropore/millipore filter on a lo/hi vol and count it in LSC. You can use a lapel and assign dose from that, bioassay is the bottom line. Overhoffs are good for Boxline monitoring but sometimes croak so ya gotta watch them. Hope this helps

[St Raphael]

TAM 100D High Sensitivity Digital Tritium Monitor
Auto-ranging, the TAM100D measures tritium-in-air levels from 0.5 µCi/m3
Major components include:
inlet filter, ion trap, tritium detection ion chamber, gamma compensation ion chamber, solid state electrometer, microprocessor, display over-range alarm and pump. Alarms can be locally or remotely set and historical data is stored in nonvolatile memory for later downloading
Features
·For glove boxes, nuclear power plants,   neutron generators, cyclotron and accelerator facilities
·Ultra sensitive solid state electrometer, thermoelectrically stabilized drift-free operation
·2 x 16 character LCD display
·Automatic background and Radon subtraction
·Flow through 2.4 L ion chamber for measuring beta radiation (tritium, noble gases, etc.) in gaseous form
·Positive displacement high volume air pump, 7-9 L (5-6 L per minute flow with 30 m of air hose)
·Tritium range: 1.85 x 10-2 to 3.7 x 104 MBq/m3
·Front panel BNC input for current calibration and testing
·Front panel accessible zero-offset by potentiometer or software
·Front panel electrometer output
·Major components include: inlet filter, ion trap, tritium detection chamber, gamma compensation ion chamber, solid state electrometer, microprocessor, display alarm and pump
·Tested to MIL standard 810E Test Procedure I


Description
The TAM100D tritium monitor is used for real-time monitoring of ambient air for the presence of tritium. It makes use of an ultra-sensitive solid state electrometer to measure exceptionally low levels of tritium. The detector has independent signal processing capability and can also communicate serially with a remote display and control unit.
The detector has the ability to be placed directly in the area to be monitored, or a sample can be withdrawn with a convenient “sniffing” tube up to 100 feet long. The TAM100D ion chamber-based tritium monitor can either be stand-alone or have a separate optional ADM600 series (ratemeter) digital display and control unit for remote operation.
TAM100D employs a pump and a flow-through pneumatic system to circulate the air sample through an ion chamber. The flow through ion chamber has both air inlet and exhaust connections. Tritium activity is determined by measuring ionization within the chamber. A separate sealed gamma compensation ion chamber of identical volume is provided to account for the contribution of any background.
After the electrical subtraction of signal minus background, the net current is converted by a solid state electrometer to a voltage proportional to the tritium concentration level.

TAM-73D - High Sensitivity Portable Digital Tritium Monitor
Features
·For measurements in locations subject to tritium contamination in the ambient atmosphere
·Ultra sensitive solid state electrometer
·Portable and lightweight – Rugged non-corrosive enclosure
·Gamma and radon compensation
·Detects other emitters (14C, 41A, 55Kr, 133Xe, etc.)
·Drift-free operation
·Battery and ac operating

Description
The TAM73D tritium monitor is used for real-time monitoring of ambient air for the presence of tritium. The TAM73D is light-weight and easily carried by hand, allowing for quick response to locations which may be subject to tritium contamination. The TAM73D makes use of an ultra sensitive solid state electrometer to measure exceptionally low levels of tritium (to 1 µCi); and yet remains rugged enough to withstand the shock, vibration, temperature and humidity extremes which are prevalent in portable instrumentation applications.
The TAM73D ion chamber-based tritium monitor employs a pump and pneumatic system to circulate ambient air through the otherwise sealed tritium detection ion chamber detector.
The detector consists of a sealed ion chamber and has both air inlet and exhaust connections. Tritium activity is determined by measuring ionization within the chamber. A separate sealed gamma compensation ion chamber of identical volume is provided to account for the contribution of any background.
After the subtraction of signal minus background, the net current is converted by a solid state electrometer to a voltage proportional to the tritium concentration level. Auto-ranging, the TAM73D measures tritium-in-air levels from 1 to 105 µCi/m3 (3.7 x 10-2 to 3.7 x 104 MBq/m3). Major components include: inlet filter, ion trap, tritium detection ion chamber, gamma compensation ion chamber, solid state electrometer, microprocessor, display over-range alarm and pump. Alarms can be manually or automatically set when the concentration level drops below the preset setpoint. The TAM73D is also sensitive to radioactive particulates which contribute to the gamma background and contaminate the ion chamber.

[Travelxox]

Overhoff Technology Corporation (located in Ohio, USA) is the leading manufacturer/supplier of tritium monitoring instrumentation. Dr. Mario Overhoff will be happy to provide technical details on any application needed.  For "portable" tritium monitors, the key essential features are quick turn on, absolute temperature stability - drift-free over time. For low level measurement, the instrument must be immune to radon and not "compensated".  Overhoff monitors are the only ones on the market that truly meet these requirements.  Just call Mario @ 513-248-2400.