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Accelerator Radiation Safety Newsletter |
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An Official Publication of the Health Physics Society's Accelerator Section Circulation: 476 |
Fourth Quarter 2010 / |
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FROM THE OFFICERS The President's
Message In this final newsletter for 2010 (which you will receive early
in 2011), I discuss the status for the upcoming 2011 HPS Mid-Year Meeting,
planning for the 2011 Annual Meeting of the HPS, issues relating to the 2013
HPS Mid-Year, and a call for Section volunteers for a committee. Also in this
newsletter, you will see items from Linnea Wahl
relating to our Section’s efforts to gather nominees for HPS awards,
recognition of members’ status, and issues relating to HPS membership. Scott
Walker provides information regarding the long awaited approval of the
Accelerator ANSI Standard (N43.1). Information on upcoming meetings is also
provided in this issue in addition to our own meeting issues that I discuss
below. Sam Baker was assisted in planning the Accelerator Session for
the upcoming February 2011 HPS Mid-Year in The Past President's
Message We’ve all made our New Year’s resolutions, right? You may have
read that Ed Maher, Health Physics Society (HPS) President, has resolved to
reverse the 10-year decrease in society membership (see Health Physics
News, October 2010, available online to HPS members at https://hps.org/membersonly/publications/newsletter/).
In that same issue, the HPS Membership Committee announced its
“Member-Get-a-Member” contest. Although this promotion just
ended on December 31, 2010, don’t let that stop you from encouraging
your unaffiliated colleagues to join the society (see the Membership
Committee’s recruiting brochure).
There’s never a deadline on sharing a good thing. All of this started me wondering about the HPS Accelerator
Section membership. Have we attracted any new members lately? And how are we
doing at retaining our long-time members? I took a look at the HPS membership
directory and here’s what I found. |
Also of interest • Professional Development School OFFICERS
Eric Burgett, Idaho State University Lorraine Marceau-Day, Louisiana State University Elsa Nimmo, University of California, Berkeley Reg Ronningen, Michigan State University |
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ANSI N43.1: Radiation Safety for the Design and Operation of Particle Accelerators Approved by ANSI N43 Committee After many years of
effort (May 1996-December, 2010), the N43 committee body has approved the
ANSI N43.1 standard. The standard itself took approximately 8 years to
write. The original N43.1 standard was written for accelerators with
energy ranges from 0.1 to 100 MeV and only included
a single chapter on radiation safety. The current document was written
on a graded basis (the higher the risk, the tighter the controls) to include
all particle accelerators and addresses: Radiation Safety Program (Design,
Safety Envelope). Radiation Safety System (Radiation Control Design
Parameters), Access Control System (Interlocks and Controls), Radiation
Control System (Passive shielding and Active Beam Inhibiting Controls),
Accelerator Operations (including interlock bypasses), Operational Radiation
Safety (Radiation Monitoring, Environmental Controls & D&D),
Training. In addition the new standard has four appendices: Development
of Safety Assessment Document (SAD), Interlocked-Type Access Control Systems,
Decommissioning Program, Measurements of Radiation and Radioactivity,
Examples of Safety Standards for Commercially Available and/or
Production-Type Accelerators. Volunteer Opportunities Are you interested
in having a say about how the Health Physics Society (HPS) operates? One way
to make your voice heard is to serve on an HPS committee. The society
recently put out a call for committee volunteers, and President-elect Kathy
Pryor will make committee assignments at the midyear meeting in early
February. There are many committees in need of your expertise—see the list at http://hps.org/aboutthesociety/organization/committees/. Most have vacancies coming up that need to be filled (with the possible exception of the Homeland Security Committee, which is fully staffed). USPAS at Stony Brook University June 13-24, 2011 The U.S. Particle
Accelerator School is offering a program of graduate-level credit courses
sponsored by Stony Brook University and held in Melville, New
York from June 13-24, 2011. Two undergraduate course and nine
specialized graduate-level courses will be offered. Two courses you may
find interesting are "Medical
Applications of Accelerators" and "Project Management for
Scientists and Engineers". Please visit our website http://uspas.fnal.gov
for full course descriptions and an electronic application form. 15th International
Conference on Emerging Nuclear Energy Systems, May 15-19, 2011 –San
Francisco, California The 15th ICENES is being hosted by the Northern California Section of the American Nuclear Society and two ANS Technical Divisions – Fusion Energy Division and Operations & Power Division. ICENES has a long history as a venue for sharing ideas and research results on emerging nuclear energy technologies and applications. The complete list of conference topics can be found here.
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FROM THE CORRESPONDENTS News from the Spallation
Neutron Source, Oak Ridge National Laboratory SNS is entering one of two annual six-week-long maintenance
periods. For the last month of the latest production run, SNS ran with
1 MW of protons on target with over 90% availability for users during
scheduled production. This period of reliable high-power operation
provided an opportunity to perform two interesting tests with beam on target
– collecting a high-resolution gamma spectrum of stack emissions, and
analyzing activation levels in tunnel air. The majority of the radioisotopes sent to the SNS stack begin as
spallation products from the mercury target.
Many of the radioisotopes in the mercury off-gas are decayed by passage
through a delay tank or captured on filters, so the majority of the
radioactive material reaching the stack consists of short-lived positron
emitters (C-11, O-15, etc.). For
this reason, SNS monitors stack emissions using a gamma detector mounted on
the side of the stack instead of the traditional filter-based system.
Periodically, we also collect a high-resolution gamma spectrum to confirm the
predicted emissions nuclide distribution. The latest spectrum is
strongly dominated by 511 keV gammas produced from
positron annihilation, with a small amount of Ar-41 as the only other
detectable contribution. Tritium is also present in the stack exhaust,
but the reported tritium contribution is based on calculated ratios since the
tritium is not detected by the gamma detectors. The observed spectrum
is consistent with the predicted observable gamma emissions.
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