INTERNATIONAL ACCELERATOR RADIOLOGICAL PROTECTION E-MAIL (IARPE) NEWSLETTER "The Official Publication of the Accelerator Section of the Health Physics Society" (with Contributions from International Correspondents) ====================================================================== January/February 1996 Circulation: 213 Vol. 5, #1 ====================================================================== OFFICERS ====================================================================== President: Bob May, CEBAF President-Elect: Lutz Moritz, TRIUMF Past President: Nisy Ipe, SLAC Secretary: Steve Musolino, BNL Treasurer: Carter Ficklen, CEBAF Newsletter Editor: Vashek Vylet, SLAC Directors: Jeff Leavey (1998) Tracy Tipping (1998) Lorraine Day (1997) Don Cossairt (1997),FNAL De Vaughn Nelson (1996) Paula Trinoskey (1996),LLNL ====================================================================== CONTENTS From the Editor From the President Feature article: Organizational Aspects and Activities related to Accelerator Shielding in Japan Readers' Feedback News from correspondents: CEBAF, ELETTRA, PAL, FERMILAB, SLAC How to subscribe or update subscription Closing thoughts >From the Editor Vashek Vylet ====================================================================== In response to my inquiry from the last issue - "Do you want IARPE on the web?" - about five of you answered "Leave it as it is". However, there was one opinionated web enthusiast, George Cicotte, who lobbied for the ways of the future: graphics, links, and all that magic. Since besides his strong opinions George also offered help, I decided to try a test IARPE issue on the web, in parallel to the listserv distribution. We hope to have it ready and announce the URL in the March/April issue. I have set up an anonymous ftp area for the web-related contributions and would be happy to send more details and instructions to anybody potentially interested in contributing to this special issue. You will notice a new "Readers' Feedback" column in this issue. Please feel free to use it to voice your opinions and/or reactions to IARPE articles. I have a subject at hand: "electronic privacy". It was suggested to me to include an e-mail directory of the Accelerator Section in one of the next issues. I was going to get an electronic version of Acc. Section directory and find matches (using a script) with the IARPE distribution list. The answer to my request from the HPS Secretariat was: "Regarding an electronic version of the HPS directory - the policy of the Society is that we do not release this information electronically." Disappointed at first, I realized that making this information widely accessible may have its downside. With a rapid increase of both user base and commercial traffic on the Internet, a boom in junk e-mail is to be expected. I need to inform you that as of now, anybody can get the IARPE distribution list by simply sending a message containing who iarpe-l to listserv@mailbox.slac.stanford.edu. If you wish, this access can be disabled. Please sent me your opinions, they will be included in the next Readers' Feedback column. In this last paragraph I shall indulge in a bit of whining: the IARPE circulation dropped from 221 in the previous issue to only 213, in spite of three new subscriptions. This is due to e-mail addresses that had to be eliminated from the list, because we were not able to contact their owners and update them. We have on average about ten mailings per issue that bounce back. Please, don't forget to update your records on the iarpe-l list whenever your e-mail address is changed. The column "How to subscribe or update subscription" is included in every issue for your convenience. >From the President Bob May ====================================================================== Greetings to all my colleagues! I want to bring you up to date on several important items: I received notification that John Taschner, the Chair of the ANSI N43 Writing Committees, has selected a Chair for N43.4 - the Accelerator writing group. Scott Walker of LANL (a member of the Accelerator Section) was recently appointed by John Taschner. Scott intends to set up a kick-off meeting in the near future and discuss availability issues with the team formed by Jack Rogers in 1994. Many of you may be wondering what became the nomination of the Accelerator Section President as an IRPA delegate. There was plenty of discussion among Accelerator Section Board members at the end of last year regarding the IRPA delegate selection process. Steve Musolino, the Accelerator Section Secretary, sent a letter to the HPS on behalf of the Section, urging the HPS to consider the Section President in the selection process. The discussion in December among the Section Board members resulted in identification of a series of concerns regarding the application (or lack thereof) of the HPS's own rules in the selection process and also the suitability of these existing rules toward meeting HPS goals for membership representation. Several draft memos registering our concerns were considered by the Section Board. Vashek Vylet made several inquiries on behalf of the Section regarding the selection process; in December of 1995 he sent a fax with questions regarding the mechanics of the selection process and, in Scottsdale, Vashek spoke with Dick Burk and outlined some of the Section Board's concerns. Ultimately, I decided that it would be better to speak with Bill Mills (HPS President) regarding the selection process. I wrote him regarding the Sections concerns and then spoke with him about what the Section could do to ensure that these concerns were properly forwarded. At Bill's suggestion I've drafted a letter to him via the Secretariat listing reflecting the Sections concerns. This draft will be forwarded to the Section Board for review before I send it. Bill promised to take it up at the May HPS Board meeting with the goal of taking appropriate actions at the Seattle meeting. Bill was very receptive to our concerns and I look forward to working with him as the HPS Board considers revising the process. I strongly suggest that you get a copy of the Ahern Report, available on the DOE WWW Home Page, which addresses external regulation of DOE activities. (DOE Home Page: http://apollo.osti.gov/html/home.html, the final report: http://www.em.doe.gov/acd/finrept.html). It seems to define nuclear facilities generally... to include all operations that involve radioactive materials or use ionizing radiation sources. Don't forget to read the end notes. I found this very disturbing as it points to a tendency toward lumping accelerator facilities in with what would normally be considered nuclear facilities; ones which actually use special nuclear material, and/or source material and produce more special nuclear material or byproduct material in their processes, etc. It seems the time for identifying a coherent set of consensus based safety requirements (or consensus document) for accelerator radiation safety is at hand. We are all being asked to do more with less and regulation as a nuclear facility could spell economic disaster for some of us. I hope to work with many of you over the next several months to identify a reasonable set of generally acceptable safety requirements and implementation measures. Hopefully, by mid 1996, the Section will be ready to issue a statement or position paper regarding the regulation of accelerator facilities. Thank you in advance for you help! Bob May Radiation Control Group Head Continuous Electron Beam Accelerator Facility FEATURE ARTICLE Hideo Hirayama ====================================================================== Organizational Aspects and Activities related to Accelerator Shielding in Japan Radiation shielding studies related to accelerators in Japan have been mainly performed within the community of the Atomic Society of Japan. Before 1980, most of research on radiation shielding was related to nuclear reactors, including fusion and casks of spent fuel. In particular, many studies were done to understand and calculate the neutron streaming, after abnormal radiation levels were observed on the Nuclear Ship Mutsu. Radiation shielding studies related to accelerators were continued by individual researchers involved in the accelerator field. >From 1980, the Accelerator Shielding Working Group was organized under the Research Committee on Fast Neutron Shielding of the Atomic Society of Japan. This is the start of a systematic study on accelerator shielding in Japan. The working group continued its activities under similar research committees as shown below. (A term of the research committee is limited to 4 years.) "Activities of the Accelerator Shielding Working Group" 1980-1984 Research committee on Fast Neutron Shielding The literature on neutron and photon production from thick or thin targets bombarded by charged particles had been surveyed from 14 journals and some internal reports and conference proceedings, mainly from 1965 up to June 1984. This work was prepared as annotated references and published as; T. Nakamura et al., "Bibliography of Published Papers on Neutron and Photon Emission from Thick Target Bombarded by Charged Particles", Institute for Nuclear Study, University of Tokyo, INS-TS-20 (1981). T. Nakamura et al.,"Annotated References on Neutron and Photon Production from Thick Targets Bombarded by Charged Particles", Nucl. Data Tables, 32, 471(1985). 1988-1992 Research committee on Engineering of Radiation Behavior The literature on shielding experiment and calculation of high energy particles above 20 MeV had been surveyed from 13 journals from 1965 up to 1989. The literature on neutron, photon and hadron production from thick target bombarded by charged particles also had been surveyed after 1884 as a complement of the previous work. This work was prepared as annotated references and published as; H. Hirayama et al., "Annotated References of Shielding Experiment and Calculation of High Energy Particles", KEK Report 90-18(1990). 1992-now Research committee on Radiation Behavior Twenty-five accelerator shielding benchmark problems were prepared for evaluating the calculational algorithm, the accuracy of computer codes and nuclear data used in codes. This work was published as; H. Hirayama et al., "Accelerator Benchmark Problems", KEK Report 92-17 (1993). The working group is continuing its survey of thick target neutron yield data and accelerator shielding experiments as the part of the actions discussed at the specialists' meeting mentioned below. Independent from this committee work, series of experiments were performed at several cyclotron facilities like INS (Univ. of Tokyo), CYRIC (Tohoku Univ.), TIARA (JAERI Takasaki) etc., using quasi- monoenergetic neutron sources. The results of shielding experiments and activation cross sections above 20 MeV were published in various journals. For example, K. Shin et al.,"Penetration of Secondary Neutrons and Protons from a Graphite Assembly Exposed to 52-MeV Protons", Nucl. Sci. Eng. 71, 294-300(1979). Y. Uwamino et al.,"Penetration Through Shielding Materials of Secondary Neutrons and Photons generated by 52-MeV Protons", Nucl. Sci. Eng., 80,360-369(1982). M. Imamura et al., "Measurements of production cross sections of C-14 and Al-26 with high-energy neutrons up to En=30 MeV by accelerator mass spectrometry", Nucl. Instrum. Methods, B52,546-552(1988). Y. Uwamino et al.,"Measurement of Neutron Activation Cross Sections of Energy up to 40 MeV Using Semimonoenergetic p-Be Neutrons", Nucl. Sci. Eng., 111, 391-403(1992). In December 1991, the Shielding Committee of Japan proposed a new project on accelerator shielding at the NEA/Nuclear Science Committee meeting. This proposal was accepted and it was agreed to hold a Specialists' Meeting (Specialists' Meeting on Shielding Aspects of Accelerators, Targets, and Irradiation Facilities). The first meeting was held at Arlington, Texas (28-29 April, 1994) and the second one at CERN (12-13 October, 1995). The next meeting will be held at Sendai, Japan at the beginning of May, 1997. To meet the action plan agreed upon at the meeting, two working subgroups were organized under the Research Committee on Reactor Physics of JAERI:the Benchmark Problem Analysis Working Subgroup and the Attenuation Length Working Subgroup. The activities of these groups were presented at the second meeting. They are continuing the studies to round off the proposed actions till the next meeting. READERS' FEEDBACK ====================================================================== I would like to add some additional historical perspective to he most recent newsletter on the subject of Boron Neutron Capture Therapy (BNCT). It is worth mentioning that the experimental work of Kruger was driven by Goldhaber, who theoretically described the charged particle reactions by slow neutrons in 1935. The biological results of Kruger lead to the work of Sweet, Farr, Fairchild, Slatkin, Robertson and others who were responsible for conducting the early BNCT clinical studies in humans that form the basis for our current knowledge of BNCT physics and biology. >From the standpoint of physics, Ralph Fairchild recognized the reasons why the early reactor produced thermal neutron beams were therapeutically inadequate. He designed, with advice from Rossi, the first epithermal neutron beam for BNCT, and described the radiological characteristics. The foundation for all the beam physics described in the recent newsletter article was due to in large part to Fairchild's pioneering work. Ralph Fairchild also was the first to suggest that a DNA analogue could be used to deliver B-10 to glioma cells, rather than the water soluble boron compound used in the early clinical trials of the 1960s at Brookhaven and MIT. At Ralph's request, BPA was first synthesized by John Glass. Epithermal neutrons and the BPA compound are in current use in the ongoing resumption of clinical trials at the Brookhaven Medical Reactor. Ralph Fairchild was posthumously awarded the Distinguished Scientific Achievement Award this past July by the Health Physics Society. I refer the readers of the IARPE to the December 1995 issue of Health Physics for the citation. Steve Musolino NEWS FROM IARPE CORRESPONDENTS ====================================================================== News from CEBAF Bob May ---------------------------------------------------------------------- PAC10 Held at CEBAF In the tenth meeting in a series that began in 1987, the CEBAF Program Advisory Committee (PAC) met January 29-31 and heard presentations on five new experimental proposals and four letters of intent concerning future proposals, as well as updates on one previously presented proposal. An additional major task was accomplished: the PAC provided the scientific ratings for all of the Hall B experiments, to go with those provided by previous PACs for Halls A and C. Members were brought up to date concerning the recent start of the CEBAF experimental program in Hall C and were presented the initial running plans for Halls A and B. At the time of PAC10, some 542 scientists from 114 institutions in 20 countries were preparing (or conducting) the 76 experiments already recommended for approval by previous PACs. Professor John Cameron of Indiana University, director of the Indiana University Cyclotron Facility, chaired PAC10. Results of the panel's deliberations will be available by early March 1996. News from ELETTRA Alessandro Rindi ---------------------------------------------------------------------- News from the Synchrotron Radiation Facility ELETTRA, Trieste (Italy) The past year was the first year of machine operation dedicated to user experiments. The storage ring operated a total of 5024 hours, of which 3784 where dedicated to the users. The total time for machine optimization studies was decreased to a level of about 25% in the first half of the year and then to 20% by the end of the year. In 1996 this will be again reduced to 17%, which is the lower limit for successful machine understanding and improvement. The machine is run twenty-four hours per day seven days a week. From January 1995 injection was limited to once per day. A morning fill allows the linac to have a full day of optimization and maintenance, to be used for the production of radio-isotopes and in the near future to be intensely active as a driver of a Free Electron Laser (FERMI). The overall machine efficiency has been high, with a 1995 user up time in excess of 91%. At the beginning of the past year the major faults involved vacuum components of the transfer line, notably bellows. A particular source of downtime occurred early last year in the form of spurious beam dumps. Their causes were finally pin-pointed to be the propagation of higher order modes into the rf cavity sputter ion pumps. This gave rise to a fictitious instantaneous pressure increase with consequent interlock intervention. It was solved by interlocking to a Penning gauge. Storms pose a problem during the summer months and last year accounted for 17% of all down time, and is second to vacuum component failure (19%) as the cause of user down time. Elettra was constructed to operate in the range 1.5 to 2.0 GeV. The linac injector provides 1.0 GeV electrons. These are then ramped in the storage ring to the final energy. Ramping of the machine has proved to be a reproducible and standard procedure. Filling of the storage ring from January to June was made to 200 mA and increased to 250 mA afterwards. The current limit is set by the vacuum chamber cooling especially at the downstream vacuum gaskets after the bending magnets. The machine design values of 400 mA at 1.5 GeV and 200 mA at 2.0 GeV will be further increased when additional cooling upgrades have been made. The machine is routinely operated in multibunch mode with 80% contiguous filling. Closed orbit stability at the facility is excellent. Lifetime at Elettra is dominated by the Touschek effect. Lifetime for users in the "relaxed" machine condition is 18 hours at 250 mA while for an "optimized" machine it is 9 hours at the present overall rf gap voltage of 2.5 MV. Vacuum in the ring is good with better than 0.07 nTorr static pressure and a peak value of 1.5 nTorr at the light ports with 250 mA and 2.0 GeV (elsewhere 0.15 to 0.6 nTorr). These values have remained practically constant during the past year of operation. At the beginning of 1995 nine insertion device sections were already installed in the ring. During the year two additional straight sections were provided with insertion devices. The shielding for the Elettra ring was calculated for a stored beam of 2 GeV and 400 mA. The assumptions concerning the beam losses were the following: 100% of the stored beam is lost once a day at anyone point in the ring; 100% of the beam is lost three times a day all along the ring; 50% of the injection beam is lost in the injection area during each refilling. The goal for the dose rate outside the shielding was to have less than 1 mSv/h during any beam loss at contact with the concrete. Using semiempirical and MonteCarlo calculations we evaluated the thickness of concrete needed. The ring is finally shielded by 0.5 m of ordinary concrete internally and on the roof and at least 1.2 m of ordinary concrete on the external side. A network of on-line and off-line gamma and neutron radiation detectors covering the area around the ring and the site was installed since the beginnings of the commissioning period. During the commissioning we prudently added some shielding blocks around the injection area. However the assumptions proved to be very pessimistic. During the last year the maximum integrated dose around the ring reached the value of 0.3 mSv of neutron and 0.15 mSv of gamma at just a spot close to the injection area. At all the other accessible locations very little over the natural background was detected. --------------- A monthly bulletin on Elettra operation, "Elettra News", is available now on World Wide Web: http://www.elettra.trieste.it/HTML/ELETTRA_News.html News from PAL Heeseock Lee ---------------------------------------------------------------------- MOST Permits PLS Operation After a two-year review process by the Korea Institute of Nuclear Safety(KINS, based on the recommendation of the Korean Atomic Energy Safety Bureau, the Ministry of Science and Technology(MOST) issued permission for the operation of the PLS, including the linac, the storage ring and two beamlines, on December 7, 1995. The linac and the storage ring were approved to operate at 2.0 GeV nominal energy. The electron currents up to 2 A can be generated by the linac, and up to 400 mA stored in the storage ring for an x-ray scattering beamline and a photoemission beamline. ENERGY RAMPING Energy ramping of the stored electron beam has started by ramping the current of all magnets synchronously. The first energy ramping experiment was performed successfully to 2.3 GeV at 100 mA by manually increasing magnet currents. Beam energy of 2.4 GeV was achieved with 20 mA on Feb. 1. An attempt to 2.5 GeV will be made soon, which is the designed maximum capacity of all subsystems in the PLS storage ring. An automatic ramping program is also under development. PLS Now on the Web A preliminary version of the Pohang Accelerator Laboratory World Wide Web site was constructed. It includes an introduction to the laboratory, status and functions of each group, the laboratory phone book and other items. The URL of the Home Page is "http://pal.postech.ac.kr/PAL". News from Fermilab Dave Boehnlein ---------------------------------------------------------------------- Fermilab's collider run I, which began in May, 1992, came to an end on February 20, 1996. The run was divided by into runs Ia, Ib and Ic. Run Ia, which went from May '92 to June '93 collected a total luminosity of 32 pb-1 (pronounced "inverse picobarns"; this number can be thought of conceptually as the number of proton-antiproton interactions that would occur in a cross-sectional area of 1 pb [10E-36 m^2] through which the counterrotating beams both pass). At the conclusion of Run Ia, the Fermilab linac was upgraded to produce a higher intensity beam for Run Ib. Run Ib lasted from December '93 to December '95 and collected 147 pb-1, more than double the luminosity which could have been achieved before the upgrade. Run Ic, which went from January to February '96, achieved another 15 pb-1, for a total of 194 pb-1 since the collider run began. The two collider experiments, CDF and D0 have efficiencies around 80% for using the luminosity. The highlight of the collider run was, of course, the discovery of the top quark, but there is still plenty more physics to be done with the data collected as physicists search for new phenomena and continue to put the Standard Model to the test. We are now looking forward to our fixed-target run, which will begin early this summer. News from SLAC Vashek Vylet ---------------------------------------------------------------------- 1. Update on the midyear meeting in San Jose As most of you know from previous issues, the 1997 midyear HPS meeting will take place on January 5-8 in San Jose, California. The technical program on the topic "Health Physics of Radiation Generating Machines" is organized by the Accelerator Section. For those not familiar with this wonderful place: San Jose is located in the heart of the Silicon Valley. As part of the metropolitan web surrounding the San Francisco bay, it offers an eclectic mixture of high technology, gastronomy, rich cultural life and sightseeing opportunities. Additional popular destinations, such as the Monterey Bay, Santa Cruz and the Napa-Sonoma wine country, are all within driving distance. The above is an appetizer cut out of the "Call for Papers" that will appear in the April issue of the HPS Newsletter. Thanks to help from a few IRPA delegates, it will also be distributed at the IRPA meeting in Vienna, together with informative brochures about San Jose. The Call for Papers is the first product of the Program Committee that was set up in last December. Its composition is truly international: Lutz Moritz, co-chair (Canada) Vashek Vylet, co-chair (USA) Don Busick (USA) Herbert Dinter (Germany) Manfred Hoefert (Switzerland) Jeff Kleck (USA) Takashi Nakamura (Japan) Ralph Nelson (USA) Wade Patterson (USA) Maurizzio Pelliccioni (Italy) Potential participants will be happy to hear that the need for HPS non-members to find a sponsor has been greatly relaxed, which will make it easier especially for foreign attendees. I have recently attended the meeting of the Local Arrangements Committee and was impressed by their plans and expertise. Their experience from the '94 HPS Annual meeting in San Francisco will be very valuable. Both the Local Arrangements and the Program Committees encourage all our readers to a) consider participating, and b) spread the word about the San Jose meeting to friends and colleagues. I would be happy to send additional copies of the Call for Papers to those who do not receive the HPS Newsletter - please e-mail your request to . 2. FATE in PEP B-factory, the new hot SLAC project being build in the old PEP ring, might get a new neighbor in the near future. The LCLS (Linac Coherent Light Source) collaboration, whose ultimate goal is to built a short wavelength free electron laser (FEL) using a portion of SLAC's linac, is considering a demonstration experiment to be located in one of the access tunnels to the PEP ring. The name of the experiment is FATE (FEL Amplifier Test Experiment). It will consist of an 80 MeV S-band linac followed by a wiggler, producing a wavelength of ~1 micron. Because of the immediate proximity of the PEP-II storage rings, shielding of the facility is mainly dictated by the injection losses, mis-steering and accident scenarios in PEP-II. Shielding options versus available space, and additional radiation protection aspects are currently being studied to determine whether this project is feasible in its planned location. HOW TO SUBSCRIBE / UPDATE YOUR E-MAIL ADDRESS ====================================================================== To add yourself to the mailing list for the IARPE Newsletter, send an e-mail message to listserv@slac.stanford.edu The body of your message should contain the following command: subscribe iarpe-l Please don't forget to update your e-mail address if you move, change jobs or just change your computing environment. The update consists in canceling the old by 'unsubscribe' and submitting a new subscription, as illustrated below: unsubscribe iarpe-l your_old_email_address subscribe iarpe-l end If the body of your message, as in this example, contains more than a single line/command, it is good practice to finish with the 'end' command, especially if your mailer adds a signature. If you experience problems with subscribing/updating, please send me an e-mail to vylet@slac.stanford.edu and I will do it for you. CLOSING THOUGHTS ====================================================================== Success consists of going from failure to failure without loss of enthusiasm. --- Winston Churchill CORRECTION/ADDENDUM (distributed on 3/8/96) ====================================================================== Bob May, Accelerator Section President, would like to make the following correction/addendum to his "From the President" column in the last issue of IARPE: In the Pres. Message, I indicated Scott Walker would be chairing the ANSI N43.4 writing committee. In fact, Scott Walker and James Liu will be co-chairs of the N43.4 writing committee. The Accelerator Section is well represented by these capable colleagues who are co-chairing this committee. Scott will be attending a meeting in Washington, D.C. with the ANSI N43 group next week to discuss the direction of the N43.3 committee. Scott indicated that he would keep the membership of the Section informed of signifigant events through the IARPENL.