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Re: Low Temperature Asher



Yes it is a rf device.

It probably ran at 13.56 MHz, 27.12 MHz, 915 MHz, or 2450 MHz. These are
"Industrial, Scientific, and Medical" frequencies in which anyone can
operate without an FCC license. Your home microwave oven runs at 2450 MHz.

I have also seen equipment that runs at variable frequencies in the
hundreds of kHz region. There is also an ISM band at 40 MHz.

Yes it should be surveyed if it can not be tagged out of use. To survey,
you'll need to know the frequency. I can see two options:

1.  See if the spec sheet has the frequency and also any hint that the
output is pulsed (pulsed output is very unlikely, but it will influence the
choice of survey instrument),

2. If you can run it, do so exactly as instructed and with a dummy load,
and use a radio Shack frequency counter. Shut it off.

See what instrument you need and survey it. Like conventional HP, frequency
affects instrument selection. Pulsed sources require thermocouple or other
slow response detectors. Continuous wave output can also be handled with
common diode detectors.

If the frequency is below 300 MHz, then it is presumed that radiation,
married electric and magnetic fields, does NOT exist. It is presumed that
there are separate electric and magnetic fields. So you'll do two surveys,
one for the electric field and another for the magnetic field. Typically
the instruments have a readout box and gozinta probes. So you'll use one
readout and two probes if the frequency is below 300 MHz and one readout
and one probe if the frequency is higher.

Gordon Miller, CIH
miller22@llnl.gov

------------------------------

>A chemist friend at NIOSH is working with a very old ( 20-25 years) Low
>Temperature Asher (LTA) manufactured by International Plasma Corporation
>(Model #   PM-1640).  This device uses an RF generator and a low pressure
>pure oxygen environment to ash samples.  No manual is available.
>
>Questions for RADSAFE:
>
>Is this unit a high power RF/microwave device?
>
>It has been out of use for quite some time.  Should the device be surveyed
>for leakage?
>
>Should the device and the area be posted?
>
>Any other precautions?
>
>Thanking you in advance,
>
>Jim Key
>RP Consultant
>Humboldt Bay Power Plant
>jfk6@pge.com
>
>************************************************************************
>The RADSAFE Frequently Asked Questions list, archives and subscription
>information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html



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The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html