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

[Chris Westerfeldt]

Barney,
    The way we deal with proton induced radiation - usually gamma's - is to
use area monitors to trip the tandem low energy cup or the belt charge on
our single-ended machines - IF there is an open gate or door to the area -
AND - the radiation is above a certain level (2.5 mR/Hr in our lab).  In our
State, we are free to set that trip point wherever we want.  The State
requires any area in which the radiation can exceed 100 mR/Hr to be
interlocked so that no one may enter.
    We also use local shielding - lead lined panels - to shield hot spots
from workers.  Lastly, we encourage personnel to wear a direct reading
pocket dosimeter.  These are set to alert the wearer if the radiation level
exceeds 10 mR/Hr.
Regards,
- Chris
-- 

Chris R. Westerfeldt
Research Scientist / T.U.N.L. Radiation Safety Manager
Duke University Physics Department &
Triangle Universities Nuclear Laboratory
Science Drive, Box 90308
Durham, NC  27708-0308
Tel: (919) 660-2600
Fax: (919) 660-2634
Email: Cwest at Tunl.Duke.Edu


> From: "Doyle, Barney L" <bldoyle at sandia.gov>
> Reply-To: Symposium of Northeastern Accelerator Personnel
> <sneap at tunl.duke.edu>
> Date: Thu, 8 Nov 2007 11:40:12 -0700
> To: Symposium of Northeastern Accelerator Personnel <sneap at tunl.duke.edu>
> Conversation: Active controls to limit current of high energy protons
> Subject: [Sneap] Active controls to limit current of high energy protons
> 
> 
> 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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