[Sneap] Active controls to limit current of high energy protons

[Scott McMaster]

Hi Barney;

There are two ends to that particular stick.  You can limit the
accelerator paramaters (ie voltage/current) or you can limit the
radiation fields.

We did the later.  We put an area monitors in the sensitive areas and
then set an alarm point for the max field that our Health Physics
people could live with.  Wired the area monitors to trip the
accelerator if the setpoint is exceeded and everyone was happy.

Still need admin controls on how/when the set poits can be adjusted.

Scott McMaster. P.Eng.
-------------------------------------------------------
Manager McMaster Accelerator Laboratory
McMaster University, Hamilton Ontario.

On Thu, 8 Nov 2007 11:40:12 -0700
 "Doyle, Barney L" <bldoyle at sandia.gov> wrote:
> 
> As part of our new Ion Beam Lab (IBL) project at Sandia, a concern is
> being raised that, while we will have adequate rad shielding for nA
> currents of 10MeV protons, how do we prevent someone from increasing
> the
> current to a uA, and then the shielding is not adequate.  We have the
> same problem in our current lab, and just use administrative controls
> (i.e. the SOP limits the energy of proton beams from the tandem to
> 4.5
> MeV, and for higher energies, Rad Protection is called in and I have
> to
> be present).  Does anyone know of active engineering controls that
> could
> be used for this situation?  Any ideas out there?  This has to be a
> pretty common problem.
> 
> -Barney
> 
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