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) ====================================================================== February/March 1994 Vol. #3, #1 ====================================================================== OFFICERS ====================================================================== President: Geoff Stapleton, CEBAF Past President: Ralph Thomas, LLNL President Elect: Nisy Ipe, SLAC Secretary: Bob May, CEBAF Treasurer (designate): Joe McDonald, PNL Directors (1 year): Paula Trinoskey, LLNL Gerry Fallon, MIT BATES Directors (2 year): Jerry Miller, LAMPF Carter Ficklen, CEBAF Directors (3 year): Steve Musolino, BNL De Vaughn Nelson >From the Editor Lutz Moritz ====================================================================== As editor I have not always been happy about those submissions to the Newsletter which deal more with the politics of funding the laboratories or about machine development than about accelerator health physics. I realize that we all have an interest in these matters, but I wonder if this is the right forum to discuss them. Usually I can get more complete information on these topics by reading the TRIUMF cafeteria bulletin board or the local User's Group Newsletter or the CERN Courier. In this issue we seem to have attracted more contributions which deal with those topics for which this Newsletter was intended. David Boehnlein submitted an excellent article in which he lays out the possibilities for a 400 MeV proton beamline **dedicated** to accelerator health physics research. His article, although not initially intended for the Newsletter (and somewhat hesitantly submitted) reads like a manifesto for our organization. The accelerator health physics community ought to support such a proposal wherever it might be located; there is a real need for a permanent facility with an on-going program of measuring the fundamental parameters for shielding, activation and dosimetry and where these measurements can be repeated whenever new calculational tools or instrumentation become available. At the present time, as far as I know, the only facility dedicated to accelerator health physics measurements is the CERN 200 GeV reference field described by Manfred Hoefert in the last issue of the Newsletter. SECTION BUSINESS ====================================================================== MINUTES OF THE AD HOC ACCELERATOR SECTION MEETING AT THE MID-YEAR TOPICAL SYMPOSIUM ON RADIOACTIVE AND MIXED WASTE, ALBANY, NEW YORK FEBRUARY 12-16, 1994: In Attendance: Carter Ficklen CEBAF Paula Trinoskey LLNL Don Cossairt FNAL Joe Stencel PPPL Joe McDonald PNL Roger Kloepping LLNL Bob Casey BNL John Laferriere DuPont Dave Boehnline FNAL Bob May CEBAF (in the chair) 1. Nisy Ipe provided a copy of the San Francisco Technical Program with the following comments: All papers submitted were accepted. Those requesting an oral presentation or poster presentation were given what they requested. Those specifying either an oral or poster presentation were assigned a poster presentation. 2. Update on the evening out... Paula also mentioned that Accelerator Section members will be given priority during "sign-up" for the San Francisco Night Out. 3. Membership including recruitment... no comments from those present. 4. Finances... Joe McDonald spoke to Dick Burke at the Albany meeting and relayed concerns about the accounting system for Accelerator Section funds. Mr. Burke indicated that he would provide a detailed accounting of the Accelerator Section's financial position including deposits and expenditures to date. He also received assurance from Mr. Burke that the HPS will provide a current list of Accelerator Section members throughout the HPS. Mr. Burke indicated that he could not provided (at this time) a list of members through affiliation with IRPA. 5. Documentation and preparation of accelerator HP bibliography... Ralph Thomas sent a report which provided a draft Table of Contents for an accelerator HP bibliography. Ralph indicated that he and Wade Patterson are writing a proposal for funding at 1/2 person year. They hope to find a sponsor through the University of California. They are soliciting suggestions on additional potential sponsors. 6. History of Accelerator HP... Ralph Thomas also provided the Table of Contents for Accelerator Radiation Protection History edited by himself and Wade Patterson. The book will be published this summer by Nuclear Technology Publishing. 7. Scientific/technical matters under consideration... Don Cossairt indicated that he and Ken Kase had corresponded on this matter, and that no additional action had taken place at this time. 8. Amendments to Section Charter... Carter Ficklen indicated that he had recently corresponded with the Rules Committee which had taken no action on the IRPA affiliation membership clause for the Accelerator Section. Carter said that his recent letter brought them up-to-date and he expects that both the IRPA affiliation membership and proposed revision to the Section executive council will be adopted without problem. 9. Newsletter... no comments from those present. 10. Nomination Committee... no comments from those present. 11. Long range planning committee... Bob Casey indicated that the long range goals presented at the Atlanta Section Meeting are unmodified. Action in support of the goals by the Accelerator Section Executive Council is the next step. 12. Directory... no comments from those present. 13. Training matters... Paula Trinoskey anticipates holding a one week "workshop" at LLNL to develop an Accelerator Training Module for the RadCon Manual. An announcement will be forthcoming. Paula indicated that a recent commitment by EH to DNFSB regarding training did not cover accelerator specific training. Regarding the BNL High Rad Area Module, DOE has taken no action yet. This module is apparently in the hands of a consultant for review. Paula indicated that many organizations seem to be combining Rad Worker I and II training and, DOE is considering a single Rad Worker Training program with special modules for specific circumstances. Some general discussion followed. Paula Trinoskey mention that at least one National Lab was having difficulty getting long-time staff members through RadCon Training. Don Cossairt mentioned a DOE initiative to disassemble many DOE Orders and reassemble them into a more coherent and continuous (smaller) set of Orders. Don had concern that the Accelerator Safety Order not disappear in the process. There being no other business the meeting adjourned. FEATURE ARTICLE ====================================================================== (This article was originally presented as a talk at a workshop to consider the feasibility and potential uses of a 400 MeV proton beamline at Fermilab) Health Physics Applications for a 400 MeV Proton Beamline (David Boehnlein) Introduction The field of accelerator health physics is one in which a great deal of research remains to be done. The radiation fields which are present at accelerator facilities differ greatly in their nature and their energies from those of other nuclear facilities, where much of the health physics work is done. Research in a variety of areas, from dosimetry to development of instrumentation, is typically performed using radiation from encapsulated radioactive materials or from nuclear reactors. The results found in such radiation fields do not necessarily reflect those that would be found in the fields produced by an accelerator used for research in high-energy physics. The Radiation Physics Group at Fermilab, as at most other high-energy physics facilities, is primarily a support group. Their foremost task is to ensure radiological safety for the workers at the facility and for the public. A thorough understanding of accelerator health physics is often taken for granted by other experimenters. Therefore, when the health physicists talk of using an experimental resource such as the proposed 400 MeV beamline, some might wonder if they are not a bit like a dog chasing a car: After all, what would they do with the thing if they actually got it? This talk is intended to address that question. It will encompass work in several areas which describes the lines along which future research may be done. The potential applications of a proton beamline to health physics research include work in dosimetry, materials activation, shielding studies, software benchmarking and development of instrumentation. Dosimetry Applications High-energy neutron dosimetry is the area of dosimetry in which further work is needed most. It might surprise many high-energy physicists, who are used to dealing with energies of hundreds of GeV, to learn that in the context of neutron dosimetry, 20 MeV is "high" energy. The radiation sources which are used in the development and testing of dosimetric devices do not produce energies much higher than this. Indeed, the Department Of Energy Laboratory Accreditation Program (DOELAP) only specifies performance criteria in the energy range from 1 keV to 2 MeV, using spectra from moderated and unmoderated Cf-252, even though many DOE facilities produce neutrons of substantially higher energies. A set of studies have been performed at Fermilab (Co88) using a standard multisphere ("Bonner sphere") technique (Br60) which illustrates this problem with measured accelerator neutron spectra. Polyethylene spheres of seven different sizes were used to moderate neutrons in radiation fields at various locations around Fermilab. The neutron spectra were studied by placing a detector at the center of each sphere as well as using a bare detector to measure the unmoderated neutron field. The detectors used were either a LiI(Eu) "phoswich" scintillator, using a fast pulse to distinguish muons from neutrons, or a LiF thermoluminescent dosimeter (TLD). Both of these are sensitive to thermal neutrons which are detected through a capture reaction. By varying the size of the moderator, a different portion of the energy spectrum is observed with each successive sphere. Measurements were made at 14 sites outside of shielding at Fermilab. Although the neutron spectrum may vary considerably from one place to another at Fermilab, the overall results are shown in Table 1. Table 1. Neutrons at Fermilab Neutron Energy Fluence (%) Dose Equivalent (%) < 0.1 MeV 77 23 > 0.1 MeV 23 77 > 2 MeV 13 50 Table 1 shows that although neutrons of energy greater than 2 MeV comprise only 13% of the neutron fluence, they are responsible for 50% of the dose equivalent due to neutrons because of the higher quality factor of these neutrons. Clearly, the need for accurate high-energy neutron dosimetry exists. In November of 1992, the U.S. Department of Energy sponsored a workshop in Gaithersburg, MD to address the problems in the current state of high-energy neutron dosimetry. The above results and others were presented there. Some of the conclusions reached at the workshop were (Al93): o Neutron dosimetry at energies above 2 MeV is imprecise and inaccurate. Since the uncertainty in measurements is often on the order of 300%, neutron dosimeters are little more than neutron indicators in high-energy neutron fields. o Better dosimeters and area monitors are needed, especially at high- energy research facilities. o The response of dosimeters as a function of energy is poorly known. o There are no calibration standards for high-energy neutron detectors. o There is no serious research and development effort underway at this time to improve the state of high-energy neutron dosimetry. One of the recommendations to come out of this workshop was for a committed and available neutron source for the near- and long-term improvement of high-energy neutron dosimetry. Muon Dosimetry A muon source with energies of 100-300 MeV is also under consideration. Should such a source become available, there are potential health physics applications for it as well. The response of personal dosimeters to a mixed field of neutrons and muons has been studied at Fermilab (Co87). The neutron spectrum was measured using the Bonner Sphere technique described in the previous section. A recombination chamber was used to measure the overall quality factor of the field, but a quality factor of 1 was assumed for the muons. The results of the field characterization are shown in Table 2. Table 2. Results of muon and neutron measurements using plastic scintillators and multisphere technique normalized to 10E+12 protons on target. Data are taken from ref. 6. Particle Type Neutrons Muons Fluence (m-2 x 10E+7) 9.1 +/- 0.4 5.6 Fluence (%) 62 +/- 3 38 Absorbed Dose (mGy) 0.19 +/- 0.06 2.3 Absorbed Dose (%) 8 +/- 3 92 Dose Equivalent (mSv) 1.2 +/- 0.3 2.3 Dose Equivalent (%) 34 +/- 26 66 Quality Factor 6.2 +/- 0.2 1 Roughly 2/3 of the dose equivalent in the fields studied was due to muons. The personal dosimeters used in this study were film badges and pocket ion chambers. Film is no longer used for dosimetry at Fermilab. Given the clear need for muon dosimetry at Fermilab, it would be of interest to conduct studies involving TLDs, bubble dosimeters and electronic dosimeters as well. Dosimetry Intercomparisons Radiation dosimetry intercomparison studies are an important method for determining the state of the art. They provide indications of how various types of dosimetry perform under defined conditions. Regular intercomparison studies have been conducted at Oak Ridge National Laboratory for a number of years (Si92). Personnel Dosimetry Intercomparison Studies (PDIS) 1-12 were performed using the Health Physics Research Reactor at Oak Ridge. These studies, however, would not necessarily indicate how personnel dosimeters might respond in the radiation environments at an accelerator. Accelerators of energies up to 15 MeV were used for PDIS 13-16. The doses administered in the accelerator studies ranged from 0.6 to 10 mSv. The conclusion reached on the basis of these studies is that, under ideal conditions, 51% of the measurements of neutron dose equivalent from accelerators were within 50% of the reference value. This is compared with 60% of measurements within 50% of the reference for the HPRR studies. These results make clear one reason why there is no DOELAP requirement for high-energy neutron dosimetry: There are no dosimeters currently in service which could consistently meet such a requirement. Fermilab is currently taking part in another intercomparison study which is being conducted at Battelle Pacific Northwest Laboratory. Dosimeters were irradiated with neutrons produced from protons incident on a Be target at 28 and 50 MeV. The final results of this study are not available as of this writing. Materials Activation When the particle beams at Fermilab interact with matter, they induce radioactivity in it. Most of the dose accumulated at Fermilab is due to employees working with or around activated materials. Radio- activation of matter provides a potential pathway for radioactivity to enter the environment. Furthermore, if radioactive material is to be disposed of as waste, state and federal regulations require that it be characterized as to its content of radionuclides. Studies of material activation are thus of interest from the standpoint of radiation safety, environmental regulation and waste disposal. Isotopic Content Some studies have been conducted at Fermilab to examine the isotopic content of a variety of activated materials (Va92). In these studies, activated items were collected from a temporary storage area on site. Their gamma-ray spectrum was then analyzed using a high-purity germanium detector and multi-channel analyzer. These studies gave a rough indication of the types and relative amounts of radionuclides to be found in a random sampling of materials activated by particle beams at Fermilab. However, these studies were not comprehensive and not well-controlled, since the history of the activated items was not entirely known. Since many activated materials contain several radioisotopes with various half-lives, the relative abundance of the isotopes as a function of the time elapsed since irradiation. A comprehensive study of the relative abundance of accelerator-induced isotopes should include measured doses of radiation at a known energy for a known irradiation time. The time between irradiation and characterization should also be known. An available beamline would make such studies possible. Environmental Studies Two sources of environmental concern at a high-energy accelerator are the activation of soil and the activation of ground water. Soil and water samples could be exposed to measured doses under well-controlled conditions and the subsequent activity measured. This would remove much of the uncertainty from estimations of soil and water activation and provide confirmatory measurements for calculations. Radiation Damage Studies Studies of radiation damage to materials and equipment could also be conducted with an available beamline. The effect of radiation on materials, such as scintillators, could be measured as a function of dose. Studies are currently carried out by the CDF experiment at Fermilab to determine the degradation of its silicon vertex detector due to radiation damage. The dose is measured using TLDs. The ability to perform such studies under conditions with better experimental controls could enhance the choice of materials for detectors for high-energy physics experiments. Shielding Studies Another area of health physics which could be studied is shielding. Shielding assessments at Fermilab are conducted by computer modeling combined with the measurement of dose rates outside of existing shielding. Controlled studies of shielding effectiveness for a well-determined radiation field are rare. Experiments could be devised to expose shields of various types to such fields. Dose rates could be measured in front of and behind the shield to determine the effectiveness of different materials or geometries. Software Benchmarking Radiation shielding is typically designed using Monte Carlo computer programs, such as CASIM, FLUKA, or HETC. Such programs are generally used to simulate high-energy particles and have a low energy cutoff around 50 MeV. Some of these codes have been modified to follow particles to thermal energies through the inclusion of cross section libraries. FLUKA, for example, has been so modified (Za90), and the LAHET program has been developed at Los Alamos. Such work would be especially important in incorporating improved production models into these programs, since it would be crucial to compare the predictions of such models with controlled experiments. Instrumentation Radiation detection instruments in common use at high-energy accelerators, for example the Chipmunk ion chambers used at Brookhaven and Fermilab, are not calibrated in high-energy radiation fields. Calibration is performed with radioactive sources such as AmBe or PuBe. Consequently, the response of these instruments is not well known for neutron energies above a few MeV. Measurements of the neutron response of the Chipmunks have been performed (Kr90) but the measurements do not extend to average energies above a few MeV. Since these instruments are used in areas where neutron energies are likely to be considerably higher, it would be of interest to have measurements of their response at higher energies. Conclusion This paper has attempted to cover a very broad range of possible projects which could be carried out if a beamline, such as the proposed 400 MeV proton beamline at Fermilab, were available for health physics studies. Areas for study include dosimetry, activation of materials for waste characterization and environmental studies, studies for shielding design and benchmarking of shielding software, and instrument response studies. This list is not comprehensive, but is simply intended to provide examples of areas of accelerator health physics where further research is needed. Brief summaries of some previous work in each of these areas has been presented to illustrate the extent and limitations of present knowledge and to provide a foundation for future work. The author is indebted to Don Cossairt, Vernon Cupps, Alex Elwyn, Kathy Graden, Fred Krueger and Kamran Vaziri for their suggestions and helpful discussions in the preparation of this paper. References J. D. Cossairt, A. J. Elwyn, W. S. Freeman, W. C. Salsbury, and P. M. Yurista, Measurements of Neutrons in Enclosures and Outside of Shielding at the TEVATRON, Fermilab-Conf-88/106, published in Proceedings of the 22nd Midyear Topical Meeting of the Health Physics Society, San Antonio, TX, Dec. 4-8, 1988. R. L. Bramblett, R. I. Ewing, and T. W. Bonner, A New Type of Neutron Spectrometer, Nucl. Instr. and Meth. 9, pp. 1-12, 1960. K. R. Alvar and A. Gavron, Report on High-Energy Neutron Dosimetry Workshop; November 19, 1992 at Gaithersburg, MD, Los Alamos National Laboratory publication LA-UR 93-747. J. D. Cossairt and A. J. Elwyn, "Personal Dosimetry In A Mixed Field Of High-Energy Muons And Neutrons," Health Physics, 52, 813, June, 1987. C. S. Sims and W.H. Casson, Overview of Neutron Radiation Dosimetry, course notes, Oct. 27-29, 1992, Oak Ridge, TN. K. Vaziri, V. Cupps and A. Elwyn, Isotopic Analysis Of Accelerator Induced Radioactivity In Material, Fermilab Radiation Physics Note 98, September 1992. J. M. Zazula, Implementation of a Low Energy Neutron Transport Module into a Monte Carlo Hadronic Shower Code and Its Applications for Accelerator Shielding Problems, DESY Internal Report D3-69, 1990. F. Krueger, Determining the Fast Neutron Energy Response Characteristics of Fermilab Instrumentation, Fermilab Radiation Physics Note 86, June 1990. NEWS FROM IARPENL CORRESPONDENTS ====================================================================== News from Brookhaven Steve Musolino ---------------------------------------------------------------------- Major progress was made in 1993 in the performance of the AGS- Booster. The Booster was commissioned in 1991 and performed as expected. After three months of machine studies during the last run the intensity was 1x10E+13 protons per pulse, approaching the design intensity of 1x10E+14 protons per pulse (6x10E+13 per second or 10 microA). The previous AGS record had been 1.9x10E+13 set back in 1986. Improvements were also made to the Heavy Ion intensity. In 1993 the silicon intensity was increased by a factor of ten to 9x10E+10 ions per pulse, while the gold intensity was also increased by a factor of ten to 3x10E+8 ions per pulse. The intensity for gold still requires another factor of ten increase to meet the design goal for the Relativistic Heavy Ion Collider (RHIC) which is scheduled for routine operation sometime in 1997. In sum, the Booster-AGS complex met its goals for 1993. With the major upgrade of the AGS RF system presently underway, the AGS should have the capability to meet its intensity goals for protons in 1994 using the Booster at its present intensity, although another 50% increase in proton intensity is planned for the 1994 run. News from Elettra, Trieste A. Rindi ---------------------------------------------------------------------- Since the last news of September 93, there have been several important achievements at the ELETTRA Synchrotron Radiation Source in Trieste. On October 5th a 1 GeV beam made the first full turn in the storage ring and on October 17th a current of 216 mA was stored with a lifetime of about 2 hours. Then on October 25th, a beam port was opened and the bending magnet radiation was used for the first experiments. After this, the commissioning resumed and on December 7th a beam of 380 mA at 1.1 GeV was stored. Because of problems encountered in trying to increase the energy of the beam in the Linac, a trial of ramping the energy of the beam inside the ring was made with the result that on January 20th the energy of the stored beam was increased from 1.2 GeV to 2 GeV. The following are some of the radiation protection experiences during this period: 1] The shielding block design which incorporates curved vertical sides proved to be very effective; 2] The thickness for the external shielding blocks (1.1 m of ordinary concrete or 0.75 m of heavy concrete of d = 3.8 g/cm3) calculated so as to limit the external annual dose to 0.5 Sv proved to be correct. During the initial commissioning of injection we added 0.5 m of ordinary concrete around the injection area (external lateral and 0.5 m thick roof). Also, during that period, we restricted the access to some areas in the interior of the ring around the injection point where the shielding has a thickness of 0.5 m of ordinary concrete. 3] The neutron and gamma dose-rates measured around the injection area showed some interesting features: the ratio gamma/n was less than 0.5 (ranging between 0.2 and 0.4) in the region external to the ring but increased up to 0.7 in the region internal to the ring. 4] We did not find any "preferred" point of interaction when the stored beam is lost. For all practical purposes, the detectors positioned around the ring do not seem to notice the loss of stored beam. 5] To help the machine people in their efforts to improve on the lifetime of the stored beam, we installed an ionization chamber on one of the front ends: the chamber measured the gas bremsstrahlung produced in one of the straight sections of the ring in order to try and correlate it with the gas pressure in the vacuum chamber. During these measurements we noticed unexpected random spikes in the bremsstrahlung dose-rate that reached values up to 6 times the normal level. These measurements are described in detail in an internal report that is available on request. News from FNAL Dave Boehnlein ---------------------------------------------------------------------- The Fermilab Linac has been upgraded from 200 MeV to 400 MeV and commissioning of the upgrade is now complete. The upgrade involved the last four linac drift tubes with seven modules of side-coupled cavity accelerators. In effect, the linac is now comprised of two structures: a low energy drift tube linac which accelerates H- ions from 750 keV to 116 MeV, followed by the high-energy side-coupled linac which accelerates the ions to 400 MeV for injection into the Fermilab Booster synchrotron. The intensity of the beam is now 35 mA. Since the upgraded linac delivers more beam than the booster can accept, the possibility of a 400 MeV beamline has been suggested. This would be accomplished by placing a pulsed extraction magnet just downstream of the booster chopper. A wire and laser would be used to strip the ions; protons would be accelerated in this beamline. A workshop to consider the feasibility and potential uses of such a beamline was held at Fermilab in October, 1993. The ideas ranged from atomic physics to proton therapy for cancer patients. The Radiation Physics Group at Fermilab came up with a number of very general ideas for potential health physics applications for a 400 MeV beamline, which I compiled into a presentation for the workshop (see feature article, this issue). I'm sure everybody out there can think of many more. It remains to be seen whether such a beamline will be constructed at Fermilab. As always, the primary difficulty is funding. News from KEK Hideo Hirayama ---------------------------------------------------------------------- A B-factory has been recognized as the post-TRISTAN project at KEK. The ongoing TRISTAN experiments will be completed within a few years. Fortunately, a part of the cost for the B-factory has been included in the cabinet budget plan for the next fiscal year, and this is going to be formally approved by the Diet in May. The design and construction of this large-scale project will start soon and is expected to take five years. The total cost for this reconstruction of the TRISTAN facilities is estimated at 35 billion yen. Surely, we, members of the Radiation Safety Control Center, will become busier preparing for shielding calculations, estimation of radiation levels and radio- activity, installation of monitors, and so forth. (K. Kondo) NEW REPORTS/PUBLICATIONS M. Numajiri et al., "Estimation of Nickel-63 Radioactivity in Steel and Copper Activated at High-Energy Accelerator Facilities", to be published in Appl. Radiat. Isot., also KEK Preprint 93-143. H. Hirayama et al., "Effects of Linearly Polarization and Doppler Broadening on the Exposure Buildup Factors of Low-Energy Gamma-Rays", submitted to the Proceedings of the 8th International Conference on Radiation Shielding, Arlington, Texas, April 24-28, 1994, also KEK Preprint 93-186. S. Ban et al., "Skyshine of Synchrotron Radiation", submitted to the Proceedings of the 8th International Conference on Radiation Shielding, Arlington, Texas, April 24-28, 1994, also KEK Preprint 93-193. Y. Harima et al.,"A simplified Method of Gamma-Ray Skyshine Calculations", submitted to the Proceedings of the 8th International Conference on Radiation Shielding, Arlington, Texas, April 24-28, 1994, also KEK Preprint 93-199. Y. Oki et al., "Particle Size and Fuming Rate of Radioactive Aerosols Generated during the Heat Cutting of Activated Metals", to be published in Appl. Radiat. Isot., also KEK Preprint 93-201. Y. Namito et al., "Implementation of Linearly-Polarized Photon Scattering and Doppler Broadening of Compton Scattered Photon into the EGS4 Code", submitted to the Proceedings of the 8th International Conference on Radiation Shielding, Arlington, Texas, April 24-28, 1994, also KEK Preprint 93-202. K. Shin and H. Hirayama, "A new Approximate Expression of Gamma-Ray Buildup Factors for Stratified Shields", submitted to the Proceedings of the 8th International Conference on Radiation Shielding, Arlington, Texas, April 24-28, 1994, also KEK Preprint 93-203. NEWS FROM SLAC (Vashek Vylet ) ---------------------------------------------------------------------- A second workshop on Scientific Applications of Coherent X-rays was held on February 12 at SLAC. Its purpose was to investigate potential applications of X-ray lasers, which should help to support arguments for building LCLS (Linac Coherent Light Source - described in previous issues of IARPE). The Executive Summary of the Workshop concludes with: "Such an X-ray laser should in fact lead to the same sort of revolutionary developments in x-ray studies of matter that was produced in optical studies by the introduction of the visible/UV laser". Using a portion of SLAC's linac, LCLS would achieve wavelengths of 40 to 1.5 Angstroems with electron beam of 7 to 25 GeV, respectively. The radiation protection issues at LCLS will be a combination of those encountered around high energy electron accelerators and those dealing with extremely bright synchrotron light sources. The project will be presented to a special panel of the National Academy of Sciences on March 6 and 7. RECENT PUBLICATIONS (RP-XX-X are SLAC Radiation Physics Notes) J.C. Liu, W.R. Nelson and K.R. Kase: "Gas Bremsstrahlung and Associated Photon-Neutron Shielding Calculations for Electron Storage Rings." SLAC-PUB-6449 (1994) - submitted to Health Physics W.R. Nelson: "Neutron and Photon Backgrounds Produced by the Accelerator in the Vicinity of the Positron Vault", RP-93-1 (1993) V.Vylet and S.Rokni: "Measurement of Neutron Spectra in the FFTB Enclosure Resulting from Beam Losses in the A-Line, RP-93-2 (1993) W.R. Nelson and Y.Namito: "UCHERQU - the UNIX Version of the UCHERQ-series of EGS4 User Codes", RP-93-4 (1993) K.R. Kase, S. Mao, W.R. Nelson and N. Ipe: "PEP-II Radiation Environment" RP-93-5/PEPII-TN-45 (1993) W.R. Nelson and K.R. Kase: "Shielding Calculations for the mQ Detector - Part I", RP-93-6 (1993) N. Ipe, K.R. Kase, J.C. Liu, S. Mao and W.R. Nelson: "Synchrotron Radiation Calculations for an Aluminum LER Chamber", RP-94-1/PEPII-TN-46 (1994) News from TRIUMF Lutz Moritz ---------------------------------------------------------------------- (The editor has allowed the following paragraph because it is close to home, brief and because... well, he is the editor) TRIUMF KAON project goes the way of the SSC In his budget speech on February 22 Paul Martin, the Canadian minister of finance, announced that: "Federal support will also be withdrawn for the KAON particle accelerator project, which has not been successful in securing international support." Deterred by the high cost and the influence of the scientific establishment and bureaucracy based in eastern Canada, no federal government had ever been very enthusiastic in its support for the project. As a result of this lack of a definite commitment on the part of the host country there had understandably been some hesitation on the part of foreign contributors to translate their considerable interest into realizable funding. The government then used the lack of foreign contributions as a reason for canceling KAON. After five years of feet-dragging on the part of the federal government, the cancellation came as no surprise but nevertheless as a great disappointment especially to Erich Vogt, the director of TRIUMF, who had never wavered in his enthusiasm for promoting the project both on its scientific merits and as an opportunity for Canadian technological advancement. Radiation Incident During the last high-intensity beam cycle a meson experiment directed a 280 MeV negative pi-meson beam into a 10.5 cm thick steel wall separating two experimental areas. The range of 280 MeV pi-mesons in steel is approximately 20 cm and therefore the meson beam was not stopped by the steel but penetrated into the adjoining area which was at times occupied by experimenters setting up another experiment. This condition went unrecognized for nearly five hours. The flux of mesons going into the wall was ~4E+05 per second. Measurements taken the next day during a reconstruction of the incident showed that the beam emerging from the other side of the steel wall was about 10 cm in diameter and that the charged particle dose-equivalent rate was approximately 1 mSv/h accompanied by a neutron field of approximately the same magnitude. The 'beam' rapidly spread with distance from the wall and luckily none of the experimenters worked near the wall, although they did walk back and forth through the beam on their way to and from their apparatus. The doses to the experimenters estimated from this reconstruction were below the threshold of the dosimeters which the experimenters were wearing and this was indeed found to be the case when the dosimeter were read. Nevertheless the incident caused much anxiety and has led to a review of all experiments using charged particle beams which might use magnets to bend the beams in previously unforeseen directions. The fact that we had available a continuous record from the radiation monitoring system and the central control datalogging system which record the readings of all radiation monitors and the status of the interlocked areas helped greatly in establishing upper limits on the possible exposures. MEETINGS ====================================================================== SECOND MID-YEAR MEETING OF ACCELERATOR SECTION TO BE HELD AT ARLINGTON THURSDAY APRIL 28 1994 - 11.40 to 12.50 A second mid-year meeting of the Accelerator Section of the Health Physics Society will be held on Thursday 28 April at Arlington to coincide with the ICRS-8 meeting and the AEN/NEA meeting. This meeting is scheduled during the lunchbreak period from 11:30 a.m. to 1:00 p.m. in the Astoria room. The meeting is open to all to attend and indeed anyone with an interest in accelerator radiation protection is very welcome to come and learn something about the Section's activities and to join the Section. The main business of the meeting is to provide a final update on the various activities that are planned for the San Francisco meeting to be held at the end of June. Update on Technical Program-HPS Annual Meeting Nisy Ipe ---------------------------------------------------------------------- I would like to thank all of you who submitted abstracts for the Accelerator Section Session at the Annual HPS Meeting in June. Ken Kase and I tried to accomodate all the requests. Those who asked for oral presentations were granted their choice, those who asked for poster presentations got their wish, and those who asked for poster or oral, were given poster presentations. Here is a preview the program: TECHNICAL PROGRAM ACCELERATOR SECTION WEDNESDAY, JUNE 29, 1994 Co-Chairs: Sarah Hoover, Los Alamos National Laboratory, New Mexico; Lutz Moritz, TRIUMF, Vancouver, British Columbia, Canada 8:30 a.m. - 9:15 a.m. : SYNCHROTRON RADIATION AND ITS APPLICATIONS Arthur Bienenstock, (Stanford Synchrotron Radiation Laboratory, Stanford Linear Accelerator Center, Stanford, CA) (invited paper) 9:15 a.m. - 9:30 a.m.: SYNCHROTRON RADIATION BEAMLINE SHIELDING AT THE APS. N.E. Ipe, (Stanford Linear Accelerator Center, Stanford, CA). D.R.Haeffner, E.E. Alp, S.C. Davey, R.J. Dejus, B. Lai, K.J. Randall, and D. Shu (Advanced Photon Source, Argonne National Laboratory, Argonne, IL).; and U. Hahn, (HASYLAB at DESY, Hamburg, Germany). STORAGE RINGS. D. Babusci, and M. Pelliccioni, (INFN, Laboratori Nazionali di Frascati, Italy). 9:45 a.m. - 10:00 a.m.: ZERO-DEGREE BREMSSTRAHLUNG: COMPARISON OF EGS4 CALCULATIONS WITH EXPERIMENTAL MEASUREMENTS AT 10 GEV. R.J. Donahue (Lawrence Berkeley Laboratory, Berkeley, CA.); N.E. Ipe, T.M. Jenkins, J.C. Liu, and W.R. Nelson (Stanford Linear Accelerator Center, Stanford, CA). 10:00 a.m. - 10:30 a.m.: COFFEE BREAK 10:30 a.m. - 10:45 a.m.: COMPARISON BETWEEN MONTE CARLO CALCULATIONS AND MEASUREMENTS OF THE LARGE ANGLE BREMSSTRAHLUNG SOURCE TERMS FOR ELECTRON ENERGIES BELOW 100 MEV. S. Mao, S. Rokni, V. Vylet, W.R.Nelson, K.Kase, N.Ipe, and J. C. Liu (Stanford Linear Accelerator Center, Stanford, CA). 10:45 a.m. - 11:00a.m.: MONTE CARLO CALCULATION OF SHIELDING PARAMETERS FOR SCATTERED MEGAVOLTAGE X-RAYS. James E. Rodgers, Paula L. Taylor, and George F. Popescu, (Georgetown University Medical Center, Radiation Science Dept., Washington, D.C.) 11:00 a.m. - 11:15 a.m.: DEEP SHIELDING PENETRATION CALCULATIONS FOR A 1 GEV PROTON BEAM. G.C. Moeller, E.Greenspan(UC Berkeley, Dept. of Nuclear Engineering, Berkeley, CA); R.J. Donahue (Lawrence Berkeley Laboratory, Berkeley, CA). 11:15 a.m. - 11:30 a.m.: THE RADIATION PROTECTION SYSTEMS FOR THE FINAL FOCUS TEST BEAM AT THE STANFORD LINEAR ACCELERATOR CENTER. S.H. Rokni, E.C.Benson, D.L. Burke, R.H. Iverson, T.M. Jenkins, J.C. Liu,G. Nelson, W.R. Nelson, H.E. Smith, P.G. Tenebaum, D.R. Walz, and V. Vylet, (Stanford Linear Accelerator Center, Stanford, CA). 11:30 a.m. - 11:45 a.m.: NEUTRON DOSIMETRIC INTERCOMPARISON IN THE 1993 CERN-CEC EXPERIMENT. J.C. Liu, (Stanford Linear Accelerator Center, Stanford, CA); S. Roesler (Technical Student from University of Leipzig, Leipzig, Germany) , and G.R. Stevenson (CERN, Geneva Switzerland) 11:45 a.m. - 12:00 p.m.: SPECIAL CONSIDERATIONS FOR THE RADIATION TRAINING PROGRAM AT THE SUPERCONDUCTING SUPER COLLIDER LABORATORY. S.L. Galpin, S. Revell, and G.B. Stapleton., (Superconducting Super Collider Laboratory, Dallas, TX). 12:00 p.m. - 12:30 p.m. LUNCH BREAK 12:30 p.m. - 1:30 p.m.: ACCELERATOR SECTION BOARD MEETING 1:30 p.m. - 2:30 p.m.: ACCELERATOR SECTION GENERAL MEETING POSTER SESSION 2:30 p.m. - 2:40 p.m.: Poster Introduction Co-Chairs Henry Kahnhauser, Brookhaven National Laboratory, New York Jeff Kleck, Varian Associates, Palo Alto 2:40 p.m. - 5:00 p.m.: Poster Viewing COMPARING THE RESPONSE OF AN ALBATROSS NEUTRON MONITOR, BONNER SPHERES AND A FISSION CHAMBER TO KNOWN HIGH ENERGY NEUTRON SPECTRUM IN AN ACCELERATOR BEAM LINE. L.S. Walker, Jim Koster, John L. Ullmann, Paul W. Lisowski, Stephen A. Wender (Los Alamos National Laboratory, Los Alamos, NM).; and Robert L. Mundis (SAIC Inc. Los Alamos, NM). USE OF IN-SITU GAMMA SPECTROSCOPY FOR ACTIVATION PRODUCTS AT CEBAF. R.T. May, S.O. Schwahn, K.B. Welch, and D. Dotson, (Continuous Electron Beam Accelerator Facility, Newport News, VA). ESTIMATION OF RADIONUCLIDE SPECIFIC ACTIVITIES IN ACCELERATOR ACTIVATED MATERIALS USING SURVEY INSTRUMENTATION. V.R. Cupps, K. Vaziri, and A. Elwyn (Fermi National Accelerator Laboratory, Batavia, IL). ANALYSIS OF POTENTIALLY MIXED WASTE FROM NIOBIUM CAVITY ACTIVATION AND REPROCESSING ACTIVITIES. S.O. Schwahn, R.T. May, K.B. Welch, and C. Sinclair (Continuous Electron Beam Accelerator Facility, Newport News, VA). Be-7 CONTAMINATION INCIDENT AT LAMPF. Bob Stokes, L. Scott Walker (Los Alamos National Laboratory, Los Alamos, NM) and Robert L. Mundis (SAIC Inc. Los Alamos, NM). RADIOLOGICAL SURVEY OF SURFACE AND TUNNEL AREAS AT THE SUPERCONDUCTING SUPER COLLIDER. S.Revell and V.D. Romero (Superconducting Super Collider Laboratory, Dallas, TX). AIRBORNE RADIONUCLIDE RELEASES FROM THE ANTIPROTON TARGET AT FERMILAB. K. Vaziri, V.R. Cupps, D. Boehnlein, D. Cossairt, A. Elwyn, and T. Leveling (Fermi National Accelerator Laboratory, Batavia, IL). ENVIRONMENTAL RADIATION MONITORING STATION. S.I. Baker and V.D. Romero (Superconducting Super Collider Laboratory, Dallas, TX). HEALTH PHYSICS EXPERIENCE AROUND SYNCHROTRON RADIATION BEAMLINES. R. Ryder, and M.P. Holbourn (Science and Engineering Research Council, Daresbury Laboratory, Daresbury, Warrington, Cheshire, UK). SHIELDING DESIGN OF A SECONDARY BEAM LINE AT SLAC. V. Vylet, W.R. Nelson, and S. Rokni (Stanford Linear Accelerator Center, Stanford, CA). LINAC ACCELERATOR SYSTEM (RFQ) COMMISSIONING RADIATION SURVEY RESULTS. G. Arbique, J. Lenz, S. Revell, and G. Stapleton (Superconducting Super Collider Laboratory, Dallas, TX). 2:40 p.m. - 5:00 p.m.: Poster Viewing (Continued) A STUDY OF RADIATION STREAMING THROUGH A LINAC WAVEGUIDE PENETRATION. J.S. Bull, and G.B. Stapleton (Superconducting Super Collider Laboratory, Dallas, TX); and L.S. Waters (Los Alamos National Laboratory, Los Alamos, NM). BAFFLE WALLS FOR THE MEB ACCESS SHAFTS. I. Baishev, J. Bull, J. Coyne,N. Mokhov, and G. Stapleton (Superconducting Super Collider Laboratory,Dallas, TX). Update on Social Program-HPS Annual Meeting Richard Donahue ---------------------------------------------------------------------- As you are probably all aware, the Accelerator Section of the HPS is sponsoring an evening out at the Lawrence Berkeley Laboratory and the Lawrence Hall of Science on June 30 during the HPS/SF Meeting. There will be wine, music, food, scenery and a lecture by Pief Pannofsky, former director of SLAC and presidential advisor. Being a technilogically superior group we wish to offer the opportunity to reserve tickets for this event to IARPE members via email prior to the general announcement. Cost of the evening will be $25 per person which includes transportation to and from the hotel, food and wine. If you wish to reserve tickets for this gala event please send an email to Roger Sit at by March 31. To aid in your decision making process we have included below the preliminary selection of edibles. --The LBL/LHS Organizing Committee HORS D' OEUVRES- PISSALADIERE (FRENCH TOMATO, ANCHOVY AND BLACK OLIVE TART) BLUE CASTELLO ON WALNUT BREAD WITH PEPPERED PEARS PRAWNS WRAPPED IN PROSCIUTTO BUFFET- CHICKEN SATAY WITH THAI PEANUT DIPPING SAUCE BABA GHANOUJ WITH GARLIC NAAN WEDGES ANTIPASTO TRAY MINI ROASTED BEEF TENDERLOIN SANDWICHES WITH HORSERADISH CREAM CHORIZO TOMATOES WITH MOZZARELLA, BASIL OIL AND BALSAMIC VINEGAR FROM THE MEMBERSHIP ====================================================================== Wade Patterson has asked me to inform those who might wish to contact him that his new E-mail address is: We welcome the following new subscribers: Richard Cumberlin Dennis Main Scott Williams <72133.327@compuserve.com> John Gregory Tony Jakovcevic Michael Bilicska NEW BOOK ====================================================================== "The History of Accelerator Radiation Protection" is the title of a new book which contains the professional and personal reminiscences of almost 30 authors from around the world. Copies will be available during the meeting of the Health Physics Society and at our Section Meeting, both in San Francisco in June. Many of the authors will attend. The book is edited by Wade Patterson and Ralph Thomas and is published by E.P. Goldfinch and Nuclear Technology Publishing. The book is international in scope, having contributions from Canada, Great Britain, France, Germany, Italy, Switzerland, Russia, China, Japan, and the U.S.A. The authors tell us how it really was in the early days of their careers at their accelerator laboratories. Collectively they cover the period from the days when even basic data about the interaction of radiation with matter was yet to be discovered to the present, when regulatory matters are of singular concern. Professor W.K.H. Panofsky has written an insightful foreword; next, Professor Mario Ladu gives a historical and philosophical review. These are followed by each author's individual recollections, in chronological order, beginning in the 1940s and continuing to the present day; even including a piece on the ill-fated SSC. There are numerous references and an index that includes the names of those persons, mentioned by the authors, who were influential in the field. CLOSING THOUGHTS ====================================================================== Recommendations for radiation exposure control of the British X-ray and Radium Protection Committee (1921): 1) No more than seven working hours/day. 2) Sundays and two half-days off per week. 3) As much leisure time as possible spent out of doors. 4) Annual holiday of one month or two fortnights. 5) Sisters and nurses working full-time in x-ray and radium departments should not be expected to perform other hospital duties. In "History, current status, and trends of radiation protection standards", William R. Hendee, Medical Physics, Vol. 20, No. 5, Sep/ Oct 1993.