INTERNATIONAL ACCELERATOR RADIOLOGICAL PROTECTION (IARPE) NEWSLETTER MAY 92 Vol.1, No.5 FROM THE EDITOR'S TERMINAL (Nisy Ipe ) ========================================================================= During the month of May, I had the opportunity of attending both the ANS meeting at Pasco, Washington, and the IRPA Congress at Montreal. There were several individuals from the accelerator community at both conferences. I was encouraged by the enthusiasm displayed by these individuals, for collaborative work, sharing of expertise and pooling of resources. A motto from one of my alma maters comes to mind, ``UNITY IS STRENGTH''. As long as we are willing to help each other, we don't need to re-invent the wheel! There is so much we can learn from each other. May this newsletter continue to serve as an open channel of communication for all of us! NEWS FROM BROOKHAVEN (Carl Schopfer ) ========================================================================= This year's Annual RHIC and AGS Users Meeting will take place on June 5th and 6th. For the first time, the meeting will include both AGS and RHIC users. The agenda includes: Friday, June 5 --------------------------------------------------------------------- Introduction A. Dzierba Welcoming Remarks N. Samios High Energy and Nuclear Physics at BNL M. Schwartz The AGS and Booster W. Weng Beams at the AGS P. Pile Safety at the AGS E. Lessard Scalar Meson Substructure in psi Radiative Decays F. E. Close and the Origin of the Zweig Rule RHIC Update: Construction and Experiments T. Ludham The STAR RHIC Detector J. Harris The PHENIX RHIC Detector S. Aronson Production of Antinuclei and New Particles H. Crawford Review of the Rare K-Decay Experiments S. Kettel Report from the Instrumentation Division H. Kraner The Future of HEPNET W. Lidinsky Saturday, June 6 --------------------------------------------------------------------- Overview of Physics at the AGS W. Marciano QCD Phase Transitions F. Wilczek The View from Congress Hon. John Meyers The View from DoE Dr. James Decker The View from the NSF Dr. David Berley Closing Remarks Dr. N. Samios For further information, contact Elaine Zukowski, Bldg. 510F, Brookhaven National Laboratory or contact henp@bnldag. ------------------------------------------------------------------------- Setting the Pace for ALARA With the Secretary's goal of being "the pace-setter for radiological health and safety at our facilities", Admiral Watkins has recently directed that radiological protection practices be strengthened at the national laboratories and other facilities operated by DOE and its contractors. A key initiative in strengthening radiological control is increased emphasis on ALARA. This stands for the concept of maintaining exposures to radiation "As Low As Reasonably Achievable". Watkins' goals and improved ways of implementing ALARA programs were major topics of discussion at the first DOE ALARA Workshop held at Brookhaven National Laboratory (BNL), April 21-22, which was sponsored by the Office of Health. The conference was organized by the staff at the BNL ALARA Center which is within BNL's Department of Nuclear Energy (DNE). The Manager, John Baum, reflects that "The center was originally established in 1983 to study dose control and ALARA engineering at nuclear power plants. In 1988, the center was asked to help DOE strengthen the implementation of ALARA programs at contractor facilities". At this workshop 70 health physicists and radiation safety engineers from seven operations/area offices, twenty-seven contractor facilities, and five headquarters offices discussed technical aspects of the ALARA programs within DOE. The program began with a talk by Anthony Weadock of the Office of Health who updated the attendees on the DOE ALARA expectations and initiatives. This was followed by ten technical presentations by DOE contractors, and by four workshop sessions. During the workshop sessions, participants were able to exchange ideas on related improvements and issues. The attendees also participated in operational exercises to enhance their knowledge of methods used for reducing workers' radiation dose. This information exchange will stimulate further improvements in DOE contractor ALARA programs which may set the pace for ALARA programs in the nuclear industry. Copies of the workshop proceedings can be requested by calling Ellie Mitchell, Phone: (516) 282-7328, or Bruce Dionne, Phone: (516) 282- 4290. This article was contributed by Bruce Dionne. ------------------------------------------------------------------------- Recent reports from Brookhaven National Laboratory staff are listed below. They are available from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Road, Springfield, VA 22161. NUREG/CR-5620, BNL NUREG-52297 THATCH: a Computer Code for Modeling Thermal Networks of High Temperature Gas-Cooled Nuclear Reactors. P.G. Kroeger, R.J. Kennett, J. Colman and T. Ginsberg. NUREG/CR-5634, BNL NUREG-52259 Identification and Assessment of Containment and Release Management Strategies for a BNW Mark I Containment. C.C. Lin and J.R. Lehner. NUREG/CR-5798, BNL NUREG-52303 Pilot Program to Assess Proposed Basic Quality Assurance Requirements in the Medical use of By-Product Materials. E. Kaplan, K. Nelson and C.B. Meinhold. NUREG/CR-5773, BNL NUREG-52295 Selection of Models to Calculate the LLW Source Term. T.M. Sullivan. NUREG/CR-5725, BNL NUREG-52287 Progress Report on Hot Particle Studies, J.W. Baum, D. G. Kaurin, M. Waligorski, R. Bird and L.C. Sun. NUREG/CR-3469, BNL NUREG-51708 Occupational Dose Reduction at Nuclear Power Plants: an Annotated Bibliography of Selected Readings in Radiation Protection and ALARA. T.A. Kahn, D.S. Vulin, S.G. Lane and J.W. Baum. BNL-52304 A comparison of Solidification Media for the Stabilization of Low- Level Radioactive Wastes. M.G. Cowgill. BNL-52314 Review of the EPA's Radionuclide Release Analyses From the LLW Disposal Trenches Used in Support of Proposed Limits on 40CFR193. C. Pescatore and T.M. Sullivan. ---------------------------------------------------------------------- POSITIONS OPEN Brookhaven National Laboratory NS 8136 Training Position - Requires bachelor's degree in a technical field, formal education in training or equivalent background, and experience training in the areas of health physics and general safety. Will assist in the training of health physics and radiation workers using the Instructional System Development methodology. Safety and Environmental Protection Division LF 0407 Medical Associate - Requires BS in physics or equivalent, with experience in electronics and computers preferred. Responsibilities include the operation of the in-vivo neutron activation facilities, concerned primarily with the inelastic neutron scattering and prompt-gamma neutron activation systems. In addition, routine patient measurements, data analysis, system maintenance and assisting in experimental work for the system calibrations are required. Medical Department. NS 8138 Training Position - Requires BS in a technical field, or equivalent, and 6 - 8 years pertinent experience. Requires proven ability to establish, maintain and implement a diverse industrial safety training program that covers a wide range of OSHA, DOE and ANSI requirements. Performance-based training, practical (hands-on) and curricula development experience is essential. Safety and Environmental Protection Division. LF 8137 Engineering Position. - Requires BS in science; health physics and three years experience in health physics, industrial hygiene or safety engineering. Will support several departments' general safety programs with specific responsibilities, including radiation exposure control, industrial hygiene monitoring, safety engineering, program audit an oversight. Safety and Environmental Protection Division. To inquire regarding the above positions, please contact the Employment Manager, Personnel Division, Bldg. 185, Brookhaven National Laboratory, Upton, NY 11973 or telephone 516-282-2882. Associate Director for Reactor, Safety and Security - Seek candidates to take line responsibility for the Reactor, Safety and Environmental Protection, and Safeguards and Security Divisions; and to participate in the overall management of the Laboratory. Requires management experience in reactor operations, substantial background in environmental matters, and technical degree(s). To inquire, contact Martin Blume, Deputy Director, Director's Office, Bldg. 460, Brookhaven National Laboratory, Upton., NY 19973, or telephone 516-282-3735. NEWS FROM CEBAF (Bob May ) ========================================================================= CEBAF Linac Cryomodule Installation Progressing Superconducting cavity pair and cryomodule production and installation are slightly ahead of schedule for the first (north) linac of the CEBAF 4 GeV recirculating accelerator. Each cryomodule contains four cavity pairs; the main accelerator will have 40 cryomodules, and the 45 MeV injector has 2 1/4 cryomodules (already in operation and validating systems design, as reported previously). In tests prior to cryomodule assembly, cavity pairs continue to perform in excess of specifications, with mean usable gradient of 8.5 MV/m (vs. 5 MV/m spec) and average Q of 5.3 E09 (vs. 2.4 E09 spec). As of early May, 7 of 20 north linac cryomodules were installed, and preparations were beginning for initial north linac tests. NEWS FROM CERN (Alberto Fasso' ) ========================================================================= The first beam from the PS Booster has been supplied to the new ISOLDE isotope accelerator on line (formerly fed by the SC synchrocyclotron, now decommissioned). By a remarkable coincidence, the celebration, announced for May 26th, will take place exactly on the 20th anniversary of the Booster. This is a peculiar machine, where four accelerator rings share common magnet stacks and main power supplies. Initially designed to inject 800 MeV protons into the PS, it has been upgraded to 1 GeV in 1988. The first physics period of 1992 was terminated on May 11th. During this time, the LEP electron-positron collider was operated at 45+45 GeV after a rather long period of setting-up. At the same time, the SPS was getting sulphur ions from the PS and accelerated them to 200 GeV/amu. Heavy ions, while producing much less induced activity than protons in the SPS components due to the lower intensity, put usually a heavier load on the radiation protection system from the point of view of prompt radiation. Experimental sulphur ion beams have intensities of the same order as secondary beams produced by protons, but losses give about 30 times more unwanted neutrons. No more heavy ion runs are foreseen before the end of 1993, but since studies are underway to accelerate lead ions in 1994, a new shielding layout of experimental areas will have to be considered. The spring meeting of the RPC (CERN Radiation Protection Committee) was held on May 11th. This Committee is formed by Radiation Protection Authorities from our Guest Countries, France and Switzerland, by senior members of the RP Group and by representatives of the CERN Management. It meets twice a year to discuss CERN radiation protection policy and to exchange information on new projects, legislation trends and so on. This time the recent decommissioning of the neutrino cave was discussed. A representative of the Vienna IAEA Agency has recently inspected CERN's stock of depleted uranium. Such inspections take place in general once a year. Control of depleted uranium has become a major task for RP Group, from both the administrative and the technical point of view. Since a few years, in fact, depleted uranium has been classified internationally as "strategic", while at the same time its use in hadronic calorimeters has strongly increased. In 1987 a definite CERN procedure has been established, which regulates "all activities concerning import, export, transfer and use of DU and fissile materials by the Organization for purposes of scientific research". A problem arises at the end of experiments using DU, since it is not always possible to re-use it in new experiments. CERN stock has become considerable and we would much like to reduce it: is any potential customer available? NEWS FROM DESY (Herbert Dinter) ========================================================================= During the shut down up to April the last installations at the e-p- storage ring HERA have been accomplished and the two detectors (ZEUS and H1) are now in beam position and are ready for data taking. In the next weeks and months our shielding conception in the experimental halls has to prove its reliability. Radiation protection measurements during this starting period of the machine are difficult and extremely time consuming because the most important radiation source is sudden beam losses. This means that the dose of single and short radiation pulses have to be measured, a task which can only be performed by the use of integrating solid state dosimeters. Therefore, a lot of measuring positions are distributed around the shielding of each detector and all dosimeters have to be evaluated several times per week or even daily, depending on the machine conditions. Last year the electron-positron storage ring DORIS was enlarged by a `bypass' providing more space for wigglers, undulators and new beam lines for the synchrotron radiation facility HASYLAB. In these days four new beam lines (three equipped with wigglers) have gone into operation, and five more will follow in the course of 1992. At the end of the year alltogether 49 experimental areas will be available for users. In July 92 the 'International Conference on High Energy Accelerators' will take place in Hamburg. Interested persons may obtain information by e-mail from . Two papers from members of the DESY radiation group were submitted for puplication: H.Dinter and K.Tesch: Determination of Neutron Spectra Behind Lateral Shielding of High Energy Proton Accelerators. Internal Report DESY D3-70 (1991), submitted to 'Radiation Protection Dosimetry'. D.Dworak, K.Tesch and J.M.Zazula: Calculations of the Photon Dose Behind Concrete Shielding of High Energy Proton Accelerators. DESY 92-030 (1992), submitted to 'Nuclear Instruments and Methods'. NEWS FROM KEK (Hideo Hirayama ) ======================================================================== KEK-PS KEK-PS is accelerating a deuteron beam 1x10^12 dpp. M.A.Kovash proposed an experiment to measure differential cross-section for p(n,gamma)d to the KEK-PS in 1990, where n was produced by bombarding a deuteron beam on a Be target. Since it was accepted by the PS-PAC, the KEK-PS started to tune the machine for the deuteron beam acceleration. It has been successful and, in last April for three weeks, deuterons 1x10^12 dpp (1 pulse duration is 4 sec) with an energy of 5 GeV/nucleon were extracted to the East Cointer Hall for the APEX experiment (Anti- proton experiment), which happened to be the first use of the d beam at the KEK-PS. THe beam line for Kovash's experiment named as the P1 beam line will be constructed during the coming summer shut down from June 20th until September 29th. Then variable neutron beams will be available for his proposal and other experiments. (T. Suzuki) Ozone Monitoring We have been measuring the ozone produced by synchrotron radiation in the tunnel of a high-energy electron storage ring, TRISTAN, by using a Dashibi ozone monitor (Model 1006-AHJ, Dashibi Enviromental Corp., Glendal, CA). The instrument employs a simple method using UV absorption by ozone at 253.7 nm. The results of measurements were presented in the scientific journal: Health Physics, 56, 953-956, 1989. (Y. Kanda) News from KEK-Radiation Safety Control Center Head of the Center changed to Kenjiro KONDO from Kazuaki KATOH on April 1st, 1992. (K. Katoh) NEWS FROM LAMPF (Sarah Hoover ) ========================================================================= LAMPF is currently tuning up in preparation for full operations on 8 June 1992. The next couple of weeks will be full of many activities. Beam spill studies will be conducted in four different expermental areas to determine if LAMPF is in compliance with its Radiation Safety Policy for various accident scenarios. During this year's annual maintenance shutdown, extensive efforts have been underway to design and place additional shielding in areas that need extra shielding in accident situations. Another major effort at the moment is the upgrading of the stack monitoring program to ensure that the radioactive air emissions, which have always been below Environmental Protection Agency (EPA) limits, are fully in compliance with EPA regulations for such concerns as uninterruptable power and emissions characterization. To further complicate matters, Los Alamos National Laboratory is currently negotiating with the EPA and the DOE on a variance, to be able to store beyond current time limitations, mixed wastes (wastes with hazardous and radioactive components) that have no currently available treatment options. At the present time, all operations at Los Alamos that could potentially generate mixed wastes which have no treatment option are suspended until such a time that an agreement is reached. It is hoped that this difficulty will be resolved in a timely manner. NEWS FROM SLAC (Nisy Ipe ) ======================================================================== A proposal to build the Next Linear Collider Test Accelerator (NLCTA) is being finalized at SLAC. As its name suggests, NLCTA would enable rf-system R&D related to the NLC project. The NLCTA's most likely location will be in End Station B. The new construction will partially protrude out of the eastern side of the present building. NLCTA will operate in the X-band (11.4 GHz), which is 4 times higher in frequency than SLAC's S-band linac. The other design parameters are: 10 pulses/second, 2E+10 electrons/bunch, 20 bunches/pulse, resulting in a current of 0.64 uA. Using four 50-MW X-band klystrons (current state- of-the-art), the maximum achievable electron energy will be close to 600 MeV. Anticipating further improvements in klystron technology (up to 100 MW per tube), the shielding of the facility is being designed for a maximum beam energy of 1.2 GeV, and maximum beam power of 750 W. The proposal will be submitted this summer or fall; if approved, NLCTA will be built in 1993. (Vashek Vylet ) The following publications may be requested from individual authors: W. Bencivelli, E. Bertolucci, U. Bottigli, A. Del Guerra,A. Messineo, W. R. Nelson, P. Randaccio, V. Rosso, P. Russo and A. Stefanini, ``Evaluation of Elemental and Compound Semiconductors for X-Ray Digital Radiography'', Nucl. Instr. Meth. A310 (1991) 210. A. Del Guerra, W. R. Nelson and P. Russo, ``A Simple Method to Introduce K-Edge Sampling for Compounds in EGS4'', Nucl. Instr. Meth. A306 (1991) 378. R. Nelson and A. Bielajew, ``EGS - A Technology Spinoff to Medicine'', SLAC Beam Line 21 (No.1) (1991) 7. Mike Lewandowski, a D.O.E. fellow, and a graduate student from Purdue University is spending the summer with the SLAC Radiation Physics Department. Mike will be testing and investigating the use of the BTI bubble detectors (spectrometer set) and Apfel's superheated drop detectors (which are already being used at SLD) in the various accelerator environments at SLAC. If anyone is interested in collaborating with us, please contact . ===================================================================== ANNOUNCEMENTS ======================================================================== IRPA9 CONGRESS (Nisy Ipe ) ------------------------------------------------------------------------- The Ninth International Congress of the International Radiation Protection Association will be held in Vienna from April 14-20, 1996. The organizers of the Congress have indicated that if there is sufficient interest (expressed in the form of contributed papers) they are willing to organize a special session on Accelerators. In addition they are also willing to let us hold a workshop prior to the Congress. I believe this is a marvelous opportunity for all of us in the accelerator community. We have about 4 years to plan for this, and participate by contributing papers. If you are interested in participating in a workshop, please send a message by E-Mail to both Manfred Hoefert and me. Any ideas on topics to be covered during this workshop, are welcome. ======================================================================== FEATURE ARTICLE OF THE MONTH ======================================================================== NEW, HIGHLY EFFECTIVE, NEUTRON & PHOTON SHIELDING MATERIALS by Ehud Greenspan ------------------------------------------------------------------------ Two independent events brought me to submit this article to the IARPE Newsletter: (1) I met Nisy Ipe at the Pasco ANS meeting in late April, and she encouraged me to do so; and (2) Dick McCall's Feature Article in the April issue of the IARPE Newsletter. In this article Dick writes that it is desirable to place cyclotrons for the production of radioisotopes inside the hospitals. But since in hospitals "Space is at a premium, it is always desirable and sometimes necessary to keep the shielding as thin as possible". It is my understanding that the shield thickness is determined by, primarily, the energetic neutrons (up to 7 MeV or 18 MeV for, respectively, a deuteron or a proton beam) generated by the cyclotron. Certain members of the family of new materials I'll describe, will enable one to design thinner shields than possible to obtain with conventional shielding materials (such as concrete, lead and iron). One member of the family of the new materials I recently conceived is "polynated tungsten". It consists of a tungsten powder bonded by polyethylene. The tungsten contribution to this "marriage" includes: (1) Very effective slowing down of MeV neutrons via inelastic scattering; (2) Strong epithermal and thermal neutron capture probability; (3) Relatively low-energy secondary photons; and (4) Very effective photon attenuation. The polyethylene role in the "marriage" includes: (1) Very effective slowing-down of the sub-MeV neutrons, via elastic scattering with, primarily, its hydrogen; and (2) Bonding the tungsten powder. Relative to a layered arrangement of tungsten (W) and polyethylene (poly), the homogenous polynated tungsten offers the following advantages: (1) More effective shielding ability (per unit thickness). (2) Lower cost (The high pressure/high temperature sintering process of W powder into W solid is very expensive. Moreover, relatively inexpensive W scraps can be used for the polynated W). (3) Mechinability. (4) Recastability. The latter two features can be particularly important when the shield is intended for experimental set ups. The polynated W can be reshaped when moved from one set up to another, so as to best match the shielding needs of the new experiment. Sintered W cannot be reshaped. The optimal amount of W to be loaded into poly is application dependent. It can be determined using a shield optimization code such as "SWAN" that I plan to tell you about in one of the following issues of the Newsletter. The following illustration of shielding effectiveness refers to polynated W which is loaded with 63 volume percent (v/o) W. Reactor Experiments, Inc. (shielding material manufacturers) tells me that they can manufacture such a polynated tungsten material. The neutron dose behind a 80 cm thick spherical shield for a point californium-252 spontaneous fission source is two-orders of magnitude lower, when polynated W is used instead of pure (or borated) poly (and, as you know, poly is much more effective than concrete for attenuating neutrons). The photon contribution to the dose behind the polynated W shield is negligible. The 80 cm of polynated W will attenuate the dose by more than six orders of magnitude (Dick mentions that 300 cm to 360 cm concrete was used to provide such an attenuation, when space was not a limitation). Other members of the family of new shielding materials recently conceived, include polynated titanium-hydride and polynated zirconium-hydride. The titanium-hydride is attractive due to its high hydrogen content -- almost 40% higher (per unit volume) than of water at room temperature. However, the titanium has relatively energetic secondary photons, so it should be used in combination with either a strong neutron absorber (such as boron) or a strong photon attenuator. The zirconium-hydride poses less of a problem with secondary photons, but offers also a smaller increase in the hydrogen content. These polynated metal hydrides can be highly effective for shielding against few MeV and lower energy neutrons. The new materials are, obviously, more expensive than conventional polyethylene. They could be attractive for special applications where space is at a premium. For example, in the cyclotron installations addressed by Dick McCall, it might be worthwhile to consider a two-zone shield arrangement: the inner (and, hence, relatively small volume) zone is to be made of polynated tungsten, and the outer zone is to be made of concrete. I shall be glad to provide additional information on the new materials, and to help evaluate their promise for specific applications. I can be reached via Bitnet: Ehudg@ucbcmsa; via Fax No. (510) 654-8450 and via Tel. (510) 643-9983. Ehud Greenspan is a Visiting Scholar at the Nuclear Engineering Department of the University of California at Berkeley. Among his professional interests are radiation shield design optimization. CLOSING THOUGHTS ========================================================================= All your strength is in your union, All your danger is in discord. LONGFELLOW, Hiawatha