INTERNATIONAL ACCELERATOR RADIOLOGICAL PROTECTION E-MAIL (IARPE) NEWSLETTER JUNE 92 Vol.1, No.6 FROM THE EDITOR'S TERMINAL (Nisy Ipe ) ========================================================================= In a dramatic turn of events, the House recently voted to kill the SSC (232/181). The fate of the SSC is now in the hands of the Senate. More than a billion dollars have already been invested in the project! This could mean the loss of several thousands of jobs. On behalf of all of us in the accelerator community, I would like to express our concern for the welfare and future of our colleagues at SSC and for the future of high energy physics in the U.S. We are half-way into the year, and I would be failing in my duty if I did not acknowledge the hard work and valiant efforts of all our correspondents, the people behind the scenes (or should I say behind the terminals). Therefore, I would like to take this opportunity to introduce them to you, so let's MEET THE CORRESPONDENTS ! BNL, New York---------- Carl J. Schopfer Carl is the Group Leader of the Personnel Monitoring Group at Brookhaven National Laboratory. The Group is responsible for monitoring of radiation exposures to employees and visitors per Department of Energy requirements. Monitoring is accomplished using film, TLD and and SSTND dosimeters for external exposures and bioassay and a dual scanning high purity Ge whole body counter for internally deposited radionuclides. Professional interests include bioassay for ultra trace levels (<100 aCi) of Pu-239, glow curve analysis of TLDs, nuclear track techniques and whole body counting. CEBAF, Virginia----------------- Bob May Bob, a certified health physicist, holds an undergraduate degree in Biology and currently serves as the Acting Head of the Radiation Control Group at CEBAF. His previous work experience includes conducting environmental monitoring programs around nuclear power plants. He constructed the first mobile radiation laboratory for the state of Virginia, and was also the Senior Manager in the Radiological Health Division at Norfolk Naval Shipyard. Married with four childern, Bob's hobbies are raquetball, fishing and canoeing, target shooting and bicycling. CERN, Geneva-------------- Alberto Fasso Alberto Fasso', is an Italian physicist, working in the Health Physics Group at CERN, since 1974. He spent the early part of his career in dosimetry at the Italian Commission for Nuclear Energy. He has been responsible for radiation protection at several of the CERN accelerators, and has participated in shield design studies for LEP, several yield experiments with proton and electron beams and experimental studies of hadron cascades in matter. Very active in in the field of Monte Carlo shielding calculations, Alberto has contributed significantly to the development of the FLUKA hadron transport code. He is also the co-author of a book on accelerator shielding. Alberto and Giulia (whom he met in the University choir), have four daughters, all of whom are musically inclined. He is a collector of minerals, fossils and beer mats. Fermi, Illinois------------- Alex Elwyn Alex is the Group Leader in the Rad. Phys. Staff Group at Fermilab. His main interests (if there was any time off from the bureaucratic concerns) are shielding measurements/calculations, muon and neutron measurements, spectroscopy, detector development and dosimetry. A former research scientist engaged in Nuclear Physics research, for 24 years at Argonne National Laboratory, he hopes to retire at the end of 1992 (before most of the Tiger Team Action Plan work begins). A self-proclaimed "photography nut" he also hopes to continue some health physics work (when not in his dark room) during his retirement. Alex is married and has 3 children. KEK, Japan------------- Hideo Hirayama Dr. Hirayama is Chief of the Radiation Control Office at KEK and his research interests are mainly related to radiation shielding of high-energy accelerators, especially to the evaluation of radiation fields for electron machines using the EGS4 computer code. LAMF, Los Alamos---------- Sarah Hoover Sarah Hoover has been employed as a Health Physicist at Los Alamos National Laboratory since October 1989. She is employed by the Operational Health Physics group at LANL and provides operational support to LAMPF. She received her M.S. in Health Physics from Texas A&M University in 1986 and was employed in various radiation safety functions at Texas A&M for 6 years before starting work at LAMPF. PLS, Korea--------------- Heeseock Lee Heeseock Lee, currently working towards a doctorate in Nuclear Engineering (at Seoul National Laboratory), is a research staff member of the Radiation Safety Control Group at PLS. His resposibilities include shielding calculations, dose analysis, and personal safety & interlock system design. He is also interested in radiation detection systems. His other interests include sports, modern history of Japan, and traditional science and technology in Korea. Being a firm believer in God, he is particularly interested in creation science. Heeseock is married. TEXAS------------------------- Wes Dunn Wes is a licence reviewer for Industrial Programs at the Texas Bureau of Radiation Control (BRC) in Austin, Texas, and serves also as Advisor to CRCPD committees for Accelerators and Industrial X-Rays. He has spent 7+ years working for the Health Physics Offices at the University of Illinois, Urbana, and Northwestern University. Facilities included 77 MeV electron Linac (upgraded to 100 MeV), Van de Graaf generators, an ion implanters and numerous industrial x-ray units. Trieste, Italy-------- Alessandro Rindi Dr. Rindi is a physicist at the Sincrotrone Trieste where he is resposible for the radiological aspects of the 1.5 - 2 GeV Synchrotron Radiation Facility, currently under construction. Affectionately described by some of his former American colleagues as an "aggressive Italian subject ", he has worked, in the past, at Fontenay aux Roses, France (2 years), CERN, Geneva (7 years) LBL, Berkeley (10 years) and INFN Frascati (8 years). His areas of primary interest include accelerator health physics, and instrumentation, and he has published several papers in these areas. Note: You will have the opportunity of meeting the rest of the correspondents in the next issue of the Newsletter. NEWS FROM BROOKHAVEN (Carl Schopfer ) ========================================================================= Upton, NY -- The U.S. Department of Energy's Brookhaven National Laboratory has signed a $42.7-mullion contract with Grumman Aerospace Corporation's Electronics Systems Division, to buy 373 superconducting dipole magnets. Grumman's corporate offices and primary manufacturing facilities are located in Bethpage, on Long Island, New York. The dipole magnets will be an integral part of the Relativistic Heavy Ion Collider now under construction at Brookhaven. When RHIC is completed in 1997 it will be the world foremost facility for nuclear physics research. RHIC will collide sub-atomic particles called heavy ions at high energies to recreate the hot, dense plasma of quarks and gluons believed to have existed in the early universe immediately after the Big Bang. The magnets will be used to guide the heavy ions as they circulate in opposite directions around two intersecting rings built in a tunnel 3.8 kilometers (2.5 miles) in circumference. Traveling at nearly the speed of light, the heavy ions, when collided, will slam together at extremely high energy, thus creating a plasma of quarks and gluons. The $42.7-million magnet purchase from Grumman is the single largest procurement for the RHIC Project, which is being funded by the Department of Energy with a $509-million budget, which includes research and development construction, and start-up costs. This is a copy of the press release that just came out for the RHIC Dipole contract and was submitted to the Newsletter by Steve Musolino. NEWS FROM ESRF (Elke Brauer) ========================================================================= Since the month of February, we have been commissioning our storage ring, in which we have accumulated 60 mA stored beam at 6 GeV with a 1.5 h lifetime. The injection frequency is limited to 1 Hz to maintain radiation levels below 20 microSv/h. During stable stored beam conditions no radiation is measured, as long as vacuum conditions are better than 10E-08 Torr. During the commissioning of the booster synchrotron (1991), dose rates from activated machine components were as high as 2 mSv/h. Dose rates are gradually decreasing to below 50 microSv/h with more stable stored beam conditions. The first experimental hutch is being installed this month,and will receive the first ESRF undulator beam at the end of this month. NEWS FROM ITALY (Alessandro Rindi ) ========================================================================= We are building a Synchrotron Radiation Facility on the Carso mesa, near Trieste. Trieste is a beautiful small city at the northfileern border of Italy, close to Slovenia (former Yugoslavia).The facility includes a 1.5 - 2 GeV Linac and a 2 GeV storage ring. It is a so-called third generation SR facility with large space for 11 insertion devices (wigglers and undulators) and up to 12 bending magnet beam lines. The Linac is installed underground while the ring is at ground level. The roof of the linac is made of ordinary concrete 2 m thick (up to 600 MeV), and heavy concrete of the same thickness (from 600 MeV up to its maximum energy). The Linac will be used also for FEL experiments. A permanent concrete wall 0.5 m thick constitutes the inner shield of the ring; the external and roof shields of the ring are made of blocks, consisting of both ordinary and heavy concrete (d = 3.7). The average thickness of these blocks is equivalent to 2 m of ordinary concrete. The roof is 0.5 m thick. The shielding thickness, calculated by using semi-empirical expressions and the Monte Carlo EGS program is based on an annual dose of 0.5 mSv outside the shielding, assuming typical concentrated beam losses. The lateral blocks have been designed in an original way: we tried to avoid the typical ratchet shape shielding in order to reduce the cost and the experimental hall occupancy and to insure total flexibility. We will install a series of radiation detectors around the ring, close to the vacuum chamber, to spot the beam losses and to correct the machine setting so as to minimize the losses. Some 12 semi-portable radiation monitoring stations will be installed at ``strategic'' locations in the experimental hall and on the site. The data from these stations will be fed, via computer, to the control room where they will be monitored and interpreted. Each monitoring station will have an ion chamber for the detection of gamma radiation and a BF3 counter for the neutrons. In April, the first section (at 100 MeV) of the Linac was commissioned. We had the opportunity to perform a series of measurements with the 100 MeV electron beam that define precisely the source term at that energy, its angular distribution and the attenuation factors in lead, of the cascade products at various angles for thick targets of both copper and iron. We are analysing these results and comparing them with Monte Carlo simulations. The facility should deliver the first synchrotron radiation beams to users by the second half of next year. NEWS FROM LAMPF (Sarah Hoover ) ========================================================================= A brief update from LAMPF... Production of beam began at LAMPF the week of 8 June 1992. LAMPF Health Physics staff have been busy participating in various operational readiness reviews prior to this startup. In addition, various beam spill scenarios have been set up for the purposes of shielding verification and accident dose calculations. At present, H+ beam is in production status, while H- and P- beam spills are anticipated during the week of 15 June 1992. NEWS FROM SSCL (Geoff Stapleton ) ======================================================================== The headline news from the SSCL is of course the House Vote in rejecting funding for the continuation of the supercollider. The Director Roy F Schwitters, informed the staff of the laboratory that this action was a serious blow, not only to the project, but to the future of American and world progress in science and technology. He explained that the vote in the House is the first step in the budget process as it relates to the SSC and that the appropriations process moves now to the Senate where restoration of the President's budget request will be vigorously pursued. He expressed the hope that the Senate will restore the funding and that the final appropriation, agreeable to both houses of the Congress, will provide continued support for the Super Collider. The Director also noted that the debate in the House was devoid of substantive criticism of technical progress, in contrast to earlier debates, something of which the SSCL staff can be proud. In order to muster support for the project, staff and friends have been asked to write to their Senators; in particular Senator J Bennette Johnston, Chairman of the Energy and Natural Resources Committee, (which sponsors the SSCL) 202/224-5824 C/O United States Senate, Washington DC 20510. This committee is considering conducting hearings on the SSCL funding. A time of concern for SSCL employees and everyone else in the world of big science! NEWS FROM TEXAS (Wes Dunn ) ======================================================================== While the CRCPD just finished their annual meeting in May, the working group dealing with accelerator regulations did not meet. We are still attempting to get the recommendations through channels, but time frames are up in the air. QUESTIONS? QUESTIONS? QUESTIONS? ========================================================================= Soil and Water Activation (Heeseock Lee ) ----------------------------------------------------------------------- PLS has a 2 GeV electron linac, 150 m long and 3 m below ground. I am interested in hearing from those who have had experience in soil and underground water activation. I would like to get some information to estimate the activation, so that I can control it. Any response will be appreciated. Please send a copy of the response to . ======================================================================== FEATURE ARTICLE OF THE MONTH ======================================================================== THE ADVANCED PHOTON SOURCE by H. J. Moe ---------------------------------------------------------------------- The 7-GeV Advanced Photon Source (APS) being constructed at Argonne National Laboratory is designed to produce the brightest beams of high-energy x rays ever available for research in the structure of materials, about 10,000 times brighter than is currently available. The brilliant x ray beams produced by the APS are expected to provide the most sophisticated tools known for scientists to understand the behavior of new materials and the processes by which they are formed. The brilliance of APS x rays (essentially the areal density of photons/s in a narrow energy band) should be able to reveal the precise positions of atoms as new materials are formed and the mechanisms by which these positions give materials unique properties. APS x rays will have energies high enough to probe the innermost shells and excite electrons in virtually any atomic or molecular subshell of atoms heavier than those previously studied. Construction of the machine began following the groundbreaking in June, 1990 and completion is scheduled for 1996. Just recently, the Linac Building has become available for beneficial occupancy. The machine will utilize a 200 MeV, 60 Hz electron linac (~ 23 m long) to accelerate electrons into a 15 m long section of the tunnel, which houses a 7 mm thick tungsten target (~ 2 radiation lengths) used to produce positrons. The electron gun and buncher system will deliver 50 nC/pulse (about 1.7 A of 30 ns width) at a repetition rate of 48 pps. The Linac Test Stand recently achieved successful operation of the gun and an initial accelerating section to produce 50 nC/pulse and 50 MeV electron beams. Positrons from the W converter, in the range 8-10 MeV and within the appropriate acceptance angle, will be captured by a positron linac (~ 31 m long) and accelerated to 450 MeV. A conversion ratio of 0.0083 positrons/electron in the W target and 60% transmission of the positrons in the positron linac is expected, giving a net ratio of 0.005 positrons/electron. The positron pulses are accumulated (24 each half second) in a 30.6 m circumference Positron Accumulator Ring (PAR) and injected into a 7-GeV, 2 Hz racetrack-shaped Booster Synchrotron (368 m in circumference). The positrons are accelerated to 7-GeV and injected into the Storage Ring, which has a circumference of 1104 m. Injection continues until 100 mA of circulating current (2.3E+12 positrons) is achieved. The positrons are held in a desired orbit by 80 bending magnets (each 4.5 degrees of bend) and by an accelerating rf potential which balances the energy loss per turn due to synchrotron radiation production in the bending magnets and the insertion devices. Insertion devices, called "wigglers" or "undulators", are made up of arrays of magnets of alternating magnetic fields which cause wiggles or undulations in the path of the positrons as they pass through the device. For each movement of the particle (wiggle or undulation), the particle experiences an acceleration and may radiate electromagnetic energy (photons). Since the positrons and photons are both moving at essentially the speed of light, the intensity of the photons is greatly multiplied along the path through the device, depending upon the number of magnets in the array. Similarly, bending of the particle in a magnetic field may also give rise to the emission of radiated energy. The radiated energy in the form of photons is referred to as synchrotron radiation. The radiation is emitted in the forward direction in a very intense, narrow beam. The synchrotron radiation, from the bending magnets and the insertion devices, is sent down an experimental beam line to a shielded First Optics Enclosure (FOE) where it encounters a mirror or a monochromator which deflects a portion of the beam down to another enclosure (Hutch) where the radiation is used in the various experimental investigations. The APS will have 35 bending magnet and 35 insertion device beam lines available, which can produce about 100 beams to accommodate as many as 300 investigators at one time. The shielding philosophy for the APS utilizes sufficient concrete (or equivalent thickness earth berm) as a bulk shield to achieve reasonable global shielding of accelerator components for distributed losses in the system. Localized shielding, which may consist of iron, lead, dense polyethylene or special castable shields is planned for high loss points. In some cases, exclusion zones or limited time access may be required to meet the DOE requirement of an average of 0.5 mrem/h. An APS Project limit of 100 mrem in the event of a single point loss of the entire beam at a given location has also been incorporated in the design of the shielding. Basic shielding on the Linac provides 2 m thickness of normal concrete (or a combination of concrete and earth berm of equivalent shielding ability), except for the 15 m section of the converter. Here, 0.4 m of iron and 1.6 m of concrete are used on the non-bermed side, while 0.3 m of iron and concrete-earth berm are used on the roof and other side. Local shielding of the W target with Pb and dense polyethylene is also planned. The shielding of the PAR is 1.3-1.5 m of concrete, which will be supplemented by Pb shielding of any high loss points. The shielding of the Booster Synchrotron is basically 0.8 m of concrete, or concrete-earth berm, except in the regions of injection from the PAR to the Synchrotron and extraction from the Synchrotron to the Storage Ring. Local shielding with Pb and dense polyethylene are planned for the regions of potentially high loss; namely, septum magnets, kickers and other components. Significant local shielding of the extraction region high loss points may be needed. The shielding of the Storage Ring consists of 0.8 m of normal concrete on the inner circular wall of the SR tunnel, and 0.56 m of high density concrete on the outside, or ratchet, wall, except for the part of the ratchet which is approximately normal to the tangent to the orbit. The wall for this case is 0.8 m of high density concrete, with a 0.46 m square, 0.25 m thick Pb plug, centered about the experimental beam line and backed by a 0.36 m square, 0.55 m thick normal concrete plug. Supplemental shielding of the high density concrete is provided by additional Pb placed at strategic locations to intercept and attenuate upstream bremsstrahlung which may miss the 0.25 m thick Pb plug. Because of the DOE requirement to report potential or actual doses in excess of 10 mrem/y at the site boundary, the roof shielding on the Storage Ring is 1 m of normal concrete since the ring is only 140 m from the site boundary. Shielding of the doors on the ratchet wall is accomplished by a castable shielding of 65% Pb, 34% of a neutron shield mixture and 1% of boron carbide, all contained in a door frame of 3/8 inch thick steel walls. Other planned shielding, in addition to that discussed above, consists of extra Pb in order to provide local shielding around the Storage Ring in areas of high, unexpected losses of positrons which could cause elevated readings outside of the ratchet wall on the experimental floor. Studies concerning the implication of the "top-off mode" are presently being considered. The results of the study may have an important bearing on additional shielding needs, especially in the First Optics Enclosure, for which access during this operation may be essential. Harold Moe is a certified Health Physicist working at Argonne National Laboratory, Illinois. CLOSING THOUGHTS ========================================================================= ``The better part of valour is discretion'' Shakespeare, Henry IV,I,V,4