Ionization at 80 eV?

["Pickett, Bruce D" <Bruce.Pickett@PSS.Boeing.com>]

>Someone called our office with questions about the safety of a device they
>are using. Apparently, this is some type of a mass spec device that is used
>as a helium leak detector, and which has an electrical potential across a
>cathode and anode. We were told that the "amount of radiation produced is 80
>electron volts of ionized radiation"; we don't know if this information comes
>from a label on the device, or the operator's manual, or somewhere else.
>
>In talking this over in our office here, we're not certain that ionization
>would even occur at such a low potential as 80 eV (we're normally working
>with thousands to hundreds of thousands of times this potential). However, we
>do agree that even if ionization does occur, any resulting x-rays would be so
>soft that they would be stopped by a small amount of air, so our conclusion,
>based on the little we know of this device, is that there would be no
>ionizing radiation hazard associated with its use.
>
>Now, in order to satiate our curiosity, can anyone on RADSAFE tell us what
>the lowest electrical potential would be that would result in ionization and
>the formation of x-rays. I presume that we would need to known the ionization
>potential of the materials in the device's anode, but knowing almost nothing
>of the device itself, we could only guess at what this would be made of.
>
>Bruce Pickett
>Radiation Health Protection
>The Boeing Company
>PO Box 3707 M/S 6Y-38
>Seattle, WA  98124
>(425)393-3098, FAX (425)393-3060
>bruce.d.pickett@boeing.com
>
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