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) ====================================================================== September/October 1995 Circulation: 202 Vol. 4, #5 ====================================================================== 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 Conference Announcement Feature article: The Current Status of the EGS4 Code System News from correspondents: CEBAF, FERMILAB, SLAC, CERN How to subscribe or update subscription Closing thoughts ====================================================================== >From the Editor Vashek Vylet ====================================================================== After my request for suggestions in the last issue two readers expressed their preference for left-justified text formatting in our Newsletter. In the full-justified format both left and right edges are straight, which requires insertion of additional blanks between words. Some readers find such a text less readable and prefer a "ragged right edge". I have conducted a mini-poll, asking a representative sample of our readership to let me know their preferences. Here are their votes: Left-justified: 11 Fully-justified: 5 Doesn't matter: 4 Besides being in majority, the "left-justified" party voiced their opinion with more vigor and persuasive arguments. I have a slight preference for the fully-justified format. However, I realize that if your mail reader uses a character set with proportional spacing rather than equal spacing, you end up with both ugly blank spaces and ragged right edge anyway. I have therefore accepted the voice of the majority, as you must have noticed by now. I would like to give you an update on a less futile subject, the planned HPS 1997 mid-year meeting in San Jose. As most of you know, the Accelerator Section proposed the subject "Health Physics of Radiation Generating Machines" and expressed interest in organizing the technical program. Usually, the local chapter takes care of local arrangements and also has the choice to decide whether or not to organize the technical program. Although the North California chapter (NCC) seemed to have given up the latter, due to minor miscommuni- cation, this issue and its financial aspects were not fully resolved. I have attended a recent meeting of the NCC Board of Directors on behalf of our Section and, after a short friendly discussion, we reached the following agreement: 1) The NCCHPS leaves organization of the technical program to the Accelerator Section 2) The Accelerator section will donate half of its proceeds (i.e. $1000) to a charitable program under the custody of NCCHPS, such as the Moyer Fund. I have the pleasure to announce that my colleague James Liu will be helping me as the Associate Editor of our newsletter. He was already instrumental in tracking the ten or so e-mail addresses that "bounced" after sending out the last issue. Scott Schwann asked me to correct a statement in the minutes of the Accelerator Section Board meeting in Boston, which indicates that he won the logo contest. Scott wants to make it clear that the logo was born from a joint effort with his colleague from CEBAF, Keith Welch. >From the President Bob May ====================================================================== Report on Action Items from the Boston Meeting Annual HPS Meeting: 1) Chair for the ANSI N43.2 Writing Committee I've asked the advice of several individuals who are notable for their contributions and experience in the accelerator radiation protection field. I've also spoken to several possible candidates for Chair of this group. I've contacted Tony LaMastra and will discuss details with him when he returns from a business trip. 2) Technical Session for the San Jose Mid-Year Topical Meeting on Radiation Generating Devices I refer to Vashek Vylet's note on his efforts at securing an agreement with the local chapter regarding monetary commitments made by them with the money set aside for the Technical Session organizers. After polling the Section Board, I asked Vashek (Technical Session Co-chair with Lutz Moritz) to represent the Section at a organization meeting. I wish to express my appreciation to Vashek for a fine diplomatic effort in determining the funds that should be used. 3) Committee on Accelerator Safety Order Guidance (CASOG) The Report by the CASOG regarding Accelerator Hazard Classification and Safety Device Reliability has been reviewed by the Accelerator Section Scientific/Technical Panel initiated by Nisy Ipe during her tenure as President. Don Cossairt and Ken Kase have provided valuable feedback on the report. In addition, Steve Musolino (Section Secretary) has asked Bob Youngblood at BNL to review the report. A poll of the CASOG Committee and the Accelerator Section Board with respect to the future of the CASOG has yielded a response which uniformly indicates that the CASOG should now, or in the very near future, take on an active role in evaluating pending rule making or other requirements and making recommendations to regulatory bodies as well as the management of accelerator facilities on the value of these proposals. Of course, to do this the CASOG needs an operating philosophy. I believe this philosophy is clearly indicated in the CASOG report. One way of bringing the CASOG into the limelight would be to publish the report as either a "position paper" within the auspices of the HPS or in an appropriate scientific journal. Olin Van Dyke, a CASOG member proposed the following: The AS/HPS ad hoc Committee on the Accelerator Safety Order and Guidance (CASOG) will be continued as the Committee on Accelerator (Radiation) Safety Oversight (CASO) for the following purposes: - to provide a forum for exchange of information on federal oversight of accelerator facility safety, - to promote development of consensus standards for accelerator safety within the accelerator community, - to speak for the accelerator community on matters of safety oversight to the federal sponsors of our facilities. I believe that Olin's proposal represents the consensus of the CASOG. At this point, I will pursue both and report back to the Section membership on the results. Bob May, President ===================================================================== CONFERENCE ANNOUNCEMENT Wes Dunn ===================================================================== Preliminary Announcement: 14th Accelerator Conference The International Conference on the Application of Accelerators in Research and Industry (ICAARI) will be holding its 14th conference November 6-8, 1996 in Denton, Texas (just north of Dallas/Fort Worth). A preliminary call for suggested speakers has been distributed. The ICAARI typically has one session devoted to Accelerator Radiation Safety. If you are interested in presenting a paper at this meeting, you may wish to contact Professor Jerome L. Duggan, Co-Chair at (817) 565-3252 or the following email address: stippec@cas.unt.edu They typically try to rope me into chairing the radiation safety session at the last minute. If you are interested in chairing, or co- chairing, this session, please contact me or Dr. Duggan. Feel free to direct any questions to me: Wesley M. Dunn, C.H.P., Administrator 512-834-6688 Licensing Branch 512-834-6690 (fax) (Texas) Bureau of Radiation Control wdunn@brc1.tdh.state.tx.us ===================================================================== FEATURE ARTICLE Ralph Nelson ===================================================================== The Current Status of the EGS4 Code System ------------------------------------------ The EGS4 Code System is a general-purpose package for the Monte Carlo simulation of the coupled transport of electrons and photons in an arbitrary geometry. Originally developed at SLAC in the early-1970s for use around accelerators (e.g., detector design, radiation shielding analysis, accelerator component temperature rise, etc.), EGS has also become a standard tool used by medical physicists throughout the world working on radiation treatment methods and ways of improving radiation imaging. During the last ten years most of the improvements to EGS have been made at low energies. A large part of this effort can be traced directly to medical physicists, and the standards laboratories that provide dosimetry support to them, most notably the National Research Council of Canada. Another major contribution has come from the accelerator health physics staff at KEK, and from their many collaborators throughout Japan. The primary documentation for the EGS4 Code System continues to be SLAC-265, a 400-page report that is still available, free on request, from the SLAC Radiation Physics Department. Some of the more important enhancements that have been developed for EGS since its release in 1985 include * Electron transport improvements (PRESTA) and capabilities (external E-field and B-field transport). * Photon transport additions (100-element K-shell fluorescence). * New angle-sampling algorithms (bremsstrahlung, pair production, photoelectric effect). * Additional physics processes (single scattering of electrons, polarized Compton scattering). * Cross-section upgrades (ICRU-37 stopping-power scaling), cross-section additions (bound-Compton scattering) and cross-section substitutions (RSIC data package DLC-136/PHOTOX). * Variance-reduction methods (bremsstrahlung splitting, forced-photon interactions, range rejection, etc.). * Special techniques related to detector response (Doppler broadening, K-edge sampling of compounds). * Utility user codes for studying cross sections (EXAMIN) and sub- routines for debugging (WATCH). * Code corrections and improvement of methods (sine/cosine accuracy, electron cross-section turn over). * Upgrading to a very-long period, portable random number generator. * Graphics add-ons (EGS-Windows, SHOWGRAF). The best way to find out more about these improvements---as well as other new features and plans for EGS---is to browse through the EGS Home Page on the World Wide Web, which can be addressed with http://egssun.lbl.gov/egs/egs.html On the Web you will learn about the various ways of obtaining the code, how to become a member of the LISTSERV discussion group, and many other things. ====================================================================== NEWS FROM IARPE CORRESPONDENTS ====================================================================== News from CEBAF Bob May ---------------------------------------------------------------------- On 1 September 1995, the CEBAF accelerator for the first time produced cw beam in 4 GeV, five-pass operation. As reported earlier, pulsed beam had previously been run at the 4 GeV design energy in a design-maximum five full passes through the recirculating machine's pair of linked superconducting linacs. The recent cw operation followed methodical efforts to eliminate a small number of aperture restrictions. The cw beam's maximum current was 16 microamperes, within a safety envelope of 25 microamperes for this phase of commissioning. Design current is 200 microamperes. Physics research will start this fall with 4 GeV cw beam at the current requested by experimenters. News from FERMILAB Dave Boehnlein ---------------------------------------------------------------------- We've just finished a shutdown period during which we continued construction on the Main Injector and a line to bring 8 GeV protons to it from the Booster synchrotron. We are now bringing the Tevatron back up to resume collider operations. This will continue, with another shutdown over the holidays, until February. We will then begin our changeover to fixed target operations. Fermilab Director John Peoples took some time to discuss the laboratory's future with staff members and I share here some of the near term projects and long term possibilities mentioned. He began by underlining the basic questions in high energy physics today. Why do particles have mass? Do neutrinos "oscillate", that is, do they change flavor between electron-type and muon-type? "Ten years ago," said Dr. Peoples, "we didn't even know how to ask these questions." Experiments to study the extremely massive top quark and to seek the as-yet unobserved tau neutrino may help to answer them. Near term projects to support such experiments include the Main Injector, upgrades to the CDF and D0 collider experiments and plans for a recycler ring. Antiproton intensity is presently limited by the number of protons which can be stochastically cooled in the antiproton accumulator. In the proposed recycler ring, antiproton intensity could be increased using electron cooling. There is also a proposal to study neutrino oscillations in a "long baseline" experiment. Neutrinos would be produced at Fermilab and aimed at a detector in Soudan, Minnesota, nearly 800 kilometers away. The neutrino beam would pass under the state of Wisconsin, as well as a good deal of Illinois and Minnesota. Finally, Dr. Peoples discussed intriguing possibilities for new machines to be considered over the long term (more than ten years hence). These included a "superluminous" Tevatron, with luminosity increased to more than 10E**33 /s/cm**2; a muon collider to produce mu + mu - collisions with 4 TeV center of mass energy; he even speculated on the possibility of an e+ e- collider at Fermilab someday. Whichever of these projects eventually comes to fruition at Fermilab, there is sure to be some very interesting physics to be done. Recent Radiation Physics Notes: Guidelines For Employing Internal Exposure Controls During The Cutting Of Activated Materials At Fermilab, Elaine Marshall, August 7, 1995; Revised 8/22/95 Approximate Technique for Evaluating the Moyer Integral in the Moyer Model of Hadron Shielding, Don Cossairt, October 1995 Approximate Technique for Estimating Labyrinth Attenuation of Accelerator Produced Neutrons, Don Cossairt, September 1995 News PLS Heeseock Lee ---------------------------------------------------------------------- The Fourth International Conference on Synchrotron Radiation Sources and The Second Asian Forum on Synchrotron Radiation are planned for October 25-27, 1995 in Hotel Hyundai near PLS. The topics are applications of Synchrotron Radiation, machine design & technology, beamline & instrumentation, machine status & future plans, international co-operation and others. Thirty three invited speakers will attend and about 120 papers will be presented. PLS will host an open house during the conference. This conference will be the first chance to formally introduce PLS to world-user community because it has just been opened to synchrotron radiation users since this September. Thirty beam runs are scheduled for synchrotron radiation users until the end of this year. News from SLAC Vashek Vylet ---------------------------------------------------------------------- The first International Workshop on Electron and Photon Transport Theory Applied to Radiation Dose Calculation was held at the Lanzl Institute on 18-22 September 1995. The Lanzl Institute is a small group of physicists, located in Seattle, Washington, who work on developing new, fast and accurate methods for performing dosimetry calculations for radiation-therapy patients. In recent years Lanzl has made significant theoretical contributions in the area of electron pencil-beam calculations, and they have used the EGS4 code to check and better understand their efforts. Other scientists around the world are also involved in similar efforts, as well as in the design of the Monte Carlo codes, and the reason for this workshop was to gather together 40 to 50 leading experts in the field. This first workshop was, in everyone's view, very useful and informative. Alex Bielajew, one of the organizers, pointed out that about 90% of the people invited were able to attend, representing eight countries. Although the primary theme of interest was medical-physics dosimetry, there was good attendance by the code writers from the U.S. national laboratories, who were able to learn first hand what is still needed in such codes as MCNP, ITS and EGS. Also of significant value was the participation by 6-8 of the leading theorists in the nuclear engineering field, who presented their ideas on using Boltzmann- Fokker-Planck-type equations for certain types of pencil-beam calculations. Macro Monte Carlo, phase-space evolution, diffusion tomographic inverse methods, new small-angle multiple-scattering theories,..... .....these were the kinds of things presented at this 5-day workshop. Although patient dosimetry seems far from the interests of accelerator health physicists and national laboratory scientists, the physics processes and the radiation transport techniques were common to all of us attending the workshop. A lot of good questions were posed and debated, in an informal and relaxed atmosphere of congeniality and respect, and a lot of insight was gained by looking at how people in different fields go about solving problems that are quite similar. The consensus of opinion was that we should try to hold another workshop of this type within the next two years. The Lanzl Institute is posting further information (e.g., attendence, list of papers and how to access them via the internet, future efforts, etc.) on their Web Home Page, which can be accessed with: http://sequoia.lanzl.com/index.html . Ralph Nelson James Liu News from CERN Alberto Fasso and Manfred Hoefert ---------------------------------------------------------------------- As usual good and bad news are mixed in life. After more than 20 years of loyal service Alberto Fasso will leave CERN to join SLAC's Radiation Physics Group. We all loved him well being a good physicists with a fantastic background in nuclear physics, his many spontaneous ideas not always practicable, and his artistic touch that seems to be an Italian tradition since the days of Leonardo. Thanks Alberto for all and good luck in your new position ! The priority for the recruitment into a new staff post, initially meant to replace Catherine Vaerman, shifted suddenly to the need for a replacement of Alberto as section leader of the important SPS/LEP section. The selection board saw two excellent candidates from a bunch of six chosen from initially 27 applications. We decided to take the best man! And it is not over yet because we shall have another selection board in November. This time for a physicist to lead the calibration and individual dosimetry section. There are some excellent specialists in this field among the applicants and we have again chosen six from this time 33 candidates to appear before the selection board. Another good news is that Lutz Moritz from TRIUMF has joined RP Group at the beginning of September as a Scientific Associate. He will work with us for one year, mainly on environmental problems in connection with the LHC collider but also with the ISOLDE installation. Here he is supported by a Norwegian post-graduate student Trond Ramsick. In the week from October 9th to 13th, two meetings were held at CERN: SARE2 (Simulating Accelerator Radiation Environments) and SATIF2 (Shielding Aspects of Accelerators, Targets and Irradiation Facilities). For both meetings, which were attended by about 50 specialists, this was the second installment (the first SARE had been held in Santa Fe in January 1993, and the first SATIF took place in Arlington in April 1994). Organizing the joint event, for which CERN s Radiation Protection Group was responsible this time, required a considerable effort but gave us the opportunity to meet again many old friends and to have long discussions until late at night in the CERN cafeteria. The proceedings will be published in a CERN Yellow Report for SARE2 and by the Nuclear Energy Agency of the Organization for Economic Cooperation and Development for SATIF2. Alberto's team has made excellent dose measurements in the LEP tunnel on the evening of the operation with 46 GeV. The results including some surprises were presented to the machine people to scare them when LEP will be tuned to 70 GeV in one weeks from now. Although we have seen the effects of synchrotron radiation at PETRA and SPEAR nobody of the engineers here at CERN will believe what an increase by a factor of ten in dose will mean for the potential damage to the LEP machine. Therefore a next measurement campaign is planned at 70 GeV to tune the machine people in to face the day when LEP will reach 86 GeV and even higher dose levels from synchrotron radiation at the end of 1997 serving then as a W-factory. One of us (MH) spent 10 days in Japan on the generous invitation of the RIKEN Laboratory in Tokyo to attend the workshop on the Radiation Safety Aspects of the RIKEN RI Beam Facility held at their premises in Wako-shi. It was rewarding to exchange information with Japanese colleagues in our field. You only can admire their knowledge and the excellent work they perform in radiation protection possibly also due to the fact that their scientific installations are still somewhat less hit by the pressure on staff numbers. The information collected in the field of individual dosimetry for neutrons during my stay in Tokyo from Nagase-Landauer (Neutrak CR39) and ALOKA (active semiconductor devices for the detection of neutrons) was particularly useful. This in view of a two day seminar on the dosimetry around high energy accelerators held in Berlin and sponsored by the German Bundesgesundheitsamt on 19/20 October. Our colleagues Herbert Dinter from DESY, Hans Festag, GSI and Christian Wernli, PSI naturally attend to make the point. I (MH) shall in particular defend the NTA film against CR39 as the most suitable method for individually monitoring the neutron exposure of more than 3000 persons at CERN regularly, reliably, and cost effectively. 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 due to changes in 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 sinle line/command, it is good practice to finish with the 'end' command, especialy 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 "I never think of the future. It comes soon enough." --- Albert Einstein