Steve

Minutes of the Accelerator Section of the Health Physics Society Annual Meeting

Minneapolis, MN

July 14, 1998

The minutes from Mobile were read by Secretary Scott Walker. Carter Ficklen moved that they be accepted as amended (items were correct, one of the persons identified was incorrect), Bob May seconded. Approved unanimously by the Section.

President Vashek Vylet read the President's Report, which was also sent out in the May/June 1998 IARPE Newsletter. Details of that report are in the report and will not be repeated in these minutes. He brought to the attention of the Section that Paula Trinoskey and Roger Kloepping were being accepted into the 1999 Fellow Class of the Health Physics Society, and the Section applauded them. Vashek also called to the attention of the Section that the 1999 Midyear Meeting in Albuquerque was in need of papers and that the deadline was July 23.

Treasurer Gerry Fallon presented the Treasurer's Report. There was $57 in expenditures and $570 in income for 1998, bringing our balance to $6302.61. It was brought up that we get no interest on Section money, and Steve Musolino indicated that he would follow up on this in his tenure as President.

Paula Trinoskey reported on efforts to organize an HPS Summer School on the topic of accelerators. She indicated that the Summer School Committee of the Section leans toward 2002 in San Diego. It was felt that the 2001 meeting in Denver was too close to adequately organize. 1999, 2000, and 2003 were all taken. An Academic Dean would be appointed through the Local Arrangements Committee.

There was further discussion on the Erice Summer School proposal. It was noted that we need to make a commitment for a series of classes every three years; we have been able to secure the support of the European Community to the tune of $30,000 US for the first year of classes. Don Cossairt brought up the question of whether we have the manpower or commitment of the Section to complete both the HPS and the Erice Summer Schools.

The need for a high energy neutron calibration facility was discussed. There was no action taken.

Scott Walker reported on Chapters 4, 5, & 6 and the new Chapter 9 of the ANSI N43.1 report. He also handed out a paper on the health physics of the Accelerator Production of Tritium project.

Vashek Vylet brought up that the Section bylaws were not at all clear on the intricacies of the election process and that perhaps they need to be clarified and written.

Steve Musolino indicated that he would once again remind the HPS Board of their verbal agreement to allow all HPS sections to elect a member as an IRPA delegate and that he would call the HPS President so that the issue will not be forgotten.

Ralph Thomas, Chairman of the Election Committee, presented the election results. There were a total of 33 votes (which although it was a small percentage of the Section, is considerably larger than attended elections prior to the new system). The new officers are:

President Elect: Joe McDonald

Secretary: Scott Schwahn

Newsletter Editor: Elaine Marshall

Board Members: Mike Grissom, Marcia Torres

Cycling off the Board are: Lutz Moritz, Jeff Leavey, Tracy Tipping

A motion was made to accept the new officers and seconded. Approved unanimously.

Scott Schwahn indicated that he would be trying to resolve e-mail address issues by the end of the year.

Paula Trinoskey brought up that there was a new ANSI Standard being worked on for multi-disciplines: Health Physics and Industrial Hygiene for technicians. There is an opening on the committee.

Vashek spoke of the need for a low-energy neutron calibration facility. He mentioned that, unlike in Europe and Japan, there is no facility in the US able to provide well defined beams of monoenergetic neutrons in a low scatter environment. The two big "standard" labs providing this service in Europe are PTB Braunschweig in Germany and NPL in Great Britain. He talked to people from these labs about their services and clients. It appears that there is no shortage of clients and their facilities are busy all year around. Accelerator generated beams at PTB and NPL range from 8 keV to 19 MeV, and the fluence is known within 3% or better. PTB is also strongly involved in another facility in Belgium (University of Louvain la Neuve), where high-energy monoenergetic neutron beams (~60 to >100 MeV) are available. Similar facilities exist in Japan, for both low and high energies. He thinks that the accelerator health physics community would greatly appreciate if such facilities were available in the US. It is not

in our power to obtain funding, but we could try join forces with other potential users and start lobbying for such a facility.

Joe McDonald suggested NIST and the University of Washington as possible resources. Carter Ficklen suggested that attaching work to an existing capital project such as the Spallation Neutron Source at Oak Ridge would be less onerous than for any lab director to come up with the money. Scott Walker suggested contacting Davis and NASA.

With a movement and a second, the meeting was adjourned.

Respectfully Submitted,

Scott O. Schwahn

Secretary

Beginning with this issue of the newsletter, the Web version has a new address. The address is: http://www-esh.fnal.gov/IARPE/. Give me a couple of days to get the current issue out there and then if you have any problems accessing the Web version, please let me know as soon as possible.

Elaine

Dan Dotson <dotson@jlab.org>, Bob May <may@jlab.org>, Scott Schwahn <schwahn@jlab.org>

One of the things that the RadCon Group has been working on for the past year is a way to access various parts of our machine without a radiological survey on initial entry. We decided to use a set of strategically placed radiation detectors (ion chamber probes) with a remote indicator and test funtion in the form of a magenta beacon at the point of entry. The ion chamber probes are placed where the injector prompt radiation source term is highest and where the probes protect areas of highest potential occupancy. The alarm settings for each probe are selected on the basis of calculations and measurements where possible. The presence of prompt radiation is indicated at the point of entry by an energized beacon. No beacon means no survey required for entry into the injector portion of the tunnel.

The process has several steps associated with it, however. First, we selected equipment similar to what is currently being used for our Controlled Area Radiation Monitoring (CARM) system. This system has certain continuous self checking features such as RAM/ROM parity and background probe counts in a given time window. Any self-check failure lights the magenta beacon at the point of entry. Next, the ion chamber probes are calibrated and source checked on a routine basis. Finally, before authorized personnel access the area, they are required to test the magenta beacon by a simple press of a button. They may not access the injector without a radiation survey either if the magenta beacon is on (indicating actual radiation in the area or equipment failure), or if it does not turn on when they press the button (also indicating equipment failure). Once the authorized personnel are in the injector, they may proceed with work. They are prevented from going into unmonitored portions of the machine by a locked and interlocked gate. The maximum energy in the injector is 5 MeV, so residual activity is not of concern. The process was tested by a Temporary Operational Safety Procedure for about a month to verify that all administrative steps were being followed and to take care of any unforseen concerns.

The ion probes used were the standard personnel protection ion probes used at Jefferson Lab. The cost of the entire system was approximately $20,000. When you consider the time we need to access the area including wait time, survey time, etc., this system will make up its value in about 150 accesses. We have no doubt that it has already made up its value. We think this is a good, reasonable response to the needs of our clients, the rest of the Laboratory.

Another area in which we will be using this type of system is in Experiment Hall B. Hall B is a permanently low-current hall, and has rarely been posted as a Radiation Area. Six of the same type of ion probes as the injector have been placed strategically in the Hall to measure residual activation. We will soon be using a similar system as that in the injector to allow limited, authorized access to the Hall without a manual survey. While the cost of the system is approximately double, the number of saved hours will also quickly make up the cost to the lab. We should note that we have considerable operational experience with the hall, and initial entries under this program will be made with a radiation survey to verify the proper use and position of the monitors, as well as the proper use of administrative controls.

The AGS has been running at high intensity since the first week in September. This followed a Booster extraction septum failure which necessitated the septum being replaced. This failure was the third separate magnet failure during the last several months at the AGS and brings attention to the aging condition of many of its beam line magnets. While experimental equipment and instrumentation has been maintained, many of the extraction magnets in the Booster and main AGS ring have undergone little maintenance during the past several years as peak beam intensities have more than tripled. These magnets tend to be heavily activated, with general area exposure rates of several R/hr half a day after shutdown. In order to keep repair-related exposures ALARA, the AGS has been removing these failed magnets to a lower background area, rather than repair them in place. The savings in exposure by working "off the girder" has more than offset the extra dose received from the added work of disconnecting and rigging the magnets.

A new record peak extracted intensity of 70.2 E12 protons was recently achieved. The previous record had been 63 E12 protons, achieved in 1995. It is our goal to achieve 100 E12 protons extracted by year's end. Higher target intensities have been cause for a renewed round of grab samples being drawn from the air inside of various target halls. The AGS target halls are unventilated spaces. Minor air exchange occurs through the base of target hall gates when building roof exhaust fans are energized. Because the target building itself is well ventilated, only negligible levels of airborne radioactive gases and particulates have been collected near target hall gates.

The C-line collimator installed earlier this year is working well. The collimator had been installed to capture scattered beam from an upstream target, and thus, to prevent it from activating downstream beam line components. The effectiveness of this collimator has been verified in several ways. First, cooling water dose rates, as measured at the base of the cooling tower which supplies C-line components, have been reduced by about a factor of 20. Second, short-lived air activity measured routinely on smears taken at the base of C-line target hall entrance gates are lower

by about a factor of 5. Third, residual dose rates from beam line elements downstream of the collimator have steadily decayed, even with higher than normal beam intensities being transported down the C-line. These lower dose residual dose rates became important when one of these magnets failed several weeks ago, and had to be rigged out for repairs.

Chuck Schaefer

Application of Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM)

We are releasing a site in accord with the December 97 MARSSIM. This is our first use of that document, so you may have learned something that we can use, or what we learn may be of use to others. Lary Martin, of the Navy's Radiological Affairs Support Office, is our regulator. Our RSO, Joe Olenik, and his supervisor, Jim Stafford, are responsible for the investigation. I am making Excel spreadsheets of the examples in Chapter 8 and Appendix I. All of our addresses are in the HPS directory.

Gordon Riel

Calculations of conversion coefficients fluence to effective dose and fluence to ambient dose equivalent for high-energy radiation have been completed. Results are available on the following references.

• Ferrari, A., Pelliccioni, M. and Pillon, M. Fluence to Effective Dose and Effective Dose Equivalent Conversion Coefficients for Photons from 50 keV to 10 GeV. Radiat. Prot. Dos. 67 245-251 (1996).
• Ferrari, A., Pelliccioni, M. and Pillon, M. High-Energy Electron and Photon Dosimetry. Health Physics of Radiation Generating Machines, Proceedings of the 30th Midyear Topical Meeting of the Health Physics Society, January 5-8, 1997, S. Jose', California (USA), 151-181 (1997).
• Ferrari, A., Pelliccioni, M. and Pillon, M. Fluence to Effective Dose and Effective Dose Equivalent Conversion Coefficients for Electrons from 5 MeV to 10 GeV. Radiat. Prot. Dos. 62(9) 97-104 (1997).

• Ferrari, A., Pelliccioni, M. and Pillon, M. Fluence to Effective Dose and Effective Dose Equivalent Conversion Coefficients for Protons from 5 MeV to 10 TeV. Radiat. Prot. Dos. 71(2) 85-91 (1997).

• Ferrari, A., Pelliccioni, M. and Pillon, M. Fluence to Effective Dose Conversion Coefficients for Neutrons up to 10 TeV. Radiat. Prot. Dos. 71(3) 165-173 (1997).

• Ferrari, A., Pelliccioni, M. and Pillon, M. Fluence to Effective Dose Conversion Coefficients for Muons. Radiat. Prot. Dos. 74(4) 227-233 (1997).

• Ferrari, A., Pelliccioni, M. and Pillon, M. Fluence to Effective Dose Conversion Coefficients for Negatively and Positively Charged Pions. Radiat. Prot. Dos. (in press)
• Pelliccioni, M. Radiation Weighting Factors and Conversion Coefficients for High-Energy Radiation, paper presented at SATIF4, Knoxville 17-18, 1998.

• Ferrari, A. and Pelliccioni, M. On the Conversion Coefficients from Fluence to Ambient Dose Equivalent, Radiat. Prot. Dosim., 51 (4), 251-255 (1994).
• Ferrari A. and Pelliccioni M., Dose Equivalents for Monoenergetic Electrons Incident on the ICRU Sphere, Radiat. Prot. Dos., 55, 207-210 (1994).
• Ferrari A. and Pelliccioni M., Dose Equivalents for Monoenergetic Positrons Incident on the ICRU Sphere, Radiat. Prot. Dos., 55, 309-312 (1994).
• Ferrari, A. and Pelliccioni, M. Fluence-to-Dose Equivalent Conversion Coefficients for Electrons and Photons of Energy up to 10 GeV. In: Proceedings 8th International Conference on Radiation Shielding, Arlington, April 24-28, 1994, 2 (1994) 893-899.

• Ferrari, A. and Pelliccioni, M. Conversion Data and Effective Quality Factors for High-Energy Neutrons, Radiat. Prot. Dosim. 76, 215-224 (1998).

• Pelliccioni, M., Fluence to Dose Equivalent Conversion Data and Radiation Weighting Factors for High-Energy Radiation, Radiat. Prot. Dosim. 77, 159-170 (1998).

Maurizio Pelliccioni

For those of you planning to attend the HPS Midyear Meeting, keep in mind that a tour of LANCE has been arranged. The October 1998 issue of the Health Physics Newsletter provides some highlights of the tour.

June 6-10, 1999

Call for Papers (due 1/8/99)

The Accelerator Application Technical Group (AATG) of the American Nuclear Society (ANS) is currently requesting the submission of summary papers for the following special sessions:

• Materials for Spallation Neutron Sources
• Safety and Thermal - Hydraulics of High-Power Accelerator (target) Systems
• Non-proliferation Issues for Accelerators
• Additional Applications for Accelerator Production of Tritium Class Accelerators
• Radiation Transport Codes and Data for Accelerator Application
• Medical Therapeutic Application of Accelerators

In addition the AATG is currently planning an embedded topical meeting (Acc-App '99) at the ANS Winter meeting in Long Beach, CA, November 14-18, 1999. Full papers will be solicited early next year in the following Accelerator Application related areas: Isotope Production/Destruction, Industrial Applications, Medical Imaging and Therapy, Nuclear Waste Transmutation, Spallation Neutron Sources, Energy Production, Neutronics tools/data, Thermal hydraulics, Materials for Accelerator Applications, Waste Management, Shielding, Safety and Source Term, Design Optimizations, Remote Handling, Systems Engineering/Integration, Target Engineering, Instrumentation and Controls, Structures, Beam Interfaces, etc. Last year's Acc-App conference in Albuquerque, NM was a tremendous success reflective of this vibrant field. Please help us continue this forum by contributing to its success.

Roger Snyder

The US Particle Accelerator School provides educational programs in the field of beams and their associated accelerator technologies not otherwise available to the community of science and technology. It promotes the development and publication of advanced technology textbooks and conducts graduate and undergraduate level courses. In January 1999, the school will hold a session at Vanderbilt University. As part of this session, a course entitled "Radiation Physics, Regulation, and Management." This course may be of interest to those who wish to improve their knowledge of accelerator radiation protection.

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