Radiation Control (RadCon) Group
Special Survey Instructions - RSS Experiment
January 23, 2002
General Guidance for Surveys in Hall C During RSS Experiment
The purpose of this document is to clarify the requirements for radiation surveys in Hall C when the polarizing target magnet is energized. The attached photos should help reinforce the description that follows.
Specific Requirements:
- Only the Teletector 6112B "yellow jacket" instrument (or alternative approved by RCG) may be used for this purpose.
- Do not attempt to obtain a contact dose rate on the target chamber or on beamline within 1 foot of the chamber.
- This survey is acceptable for a "full survey" of the hall. However, if the Whole Body dose rate at the target chamber is greater than 2 mR/hr, the RCG shall be contacted prior to allowing direct, hands-on access to the target chamber (i.e. for Restricted Access).
General Practice:
*Remember to notify the Hall C shift leader of the entry when you get to the Counting House.
- Survey other areas of the hall using the standard protocol: Whole Body dose rates along entire upstream and downstream beamline; obtain contact dose rates when the Whole Body dose rate exceeds 2 mR/hr; survey any Radiation Area/High Radiation Area boundaries to verify placement; show maximum Whole Body and contact dose rate in Radiation Areas.
- Enter the outer fence boundary (right hand side of HMS), and survey the area under the target pivot and HMS platform.
- Access the target control platform. Extend the detector through the plastic fence and do a WB survey of the accessible part of the beamline and target chamber. Do not extend the probe beyond the point that you can see it.
- Climb the stairs to the upper platform, and survey the platform area. You should be able to do an adequate survey of the area without having to climb under the instrumentation cabling by extending the detector.
- The downstream exit tubing should be checked along its entire length from the floor beneath the tube.
- From the floor survey the SOS side of the target area. The probe can be placed through the plastic fencing enough to survey the platform area. Again, there is no need to attempt contact dose rates here.
General area survey under pivot area
Typical dose rate ~ 0.2 mR/hr
Survey around HMS deck and pivot from below
Typical dose rate ~0.4 mR/hr
From the target/cryo control platform, extend probe through fence
for Whole Body survey of upstream beamline and target chamber
Typical dose rate ~ 0.4 mR/hr
From the upper target platform, survey entire upper platform area. This
can be done without passing under the cables from the target to the rack.
Typical dose rate ~0.2 mR/hr
From the floor downstream of the target, do a Whole Body survey
of the exit beamline and the SOS side of the chamber.
Typical dose rate here is normally < 1 mR/hr