Fermilab is now heavily involved in the much-needed seven-week accelerator shutdown that started September 8. One of the major jobs planned for this shutdown is a series of repairs and improvements to the 8 GeV booster to reduce beam losses and improve its performance for stable, high-intensity operations needed for the rest of the Tevatron Collider Run II, MiniBooNE, and the near future NuMI experimental research programs. As we have remarked previously, the booster now transports annually more protons than it has during its previous three decades of operation. The improvements include the addition of collimators to localize some unavoidable losses to certain well-shielded locations and the replacement of some sections of the beam line to ease aperture restrictions. Because of the high levels of residual activity at the booster, the Beams Division Head made the difficult decision to suspend operations of the MiniBooNE experiment one week early to allow time for the residual radioactivity to cool down to manageable levels. (Submitted by Kamran Vaziri.)
Another related activity was a Beams Division all-hands meeting called by the division head. The head of the Particle Physics Division that is responsible for all the experiments also spoke at this meeting since large numbers of people from that division and others are being enlisted to work in the accelerator during the shutdown. The main theme of the meeting was the importance of attention to the safety aspects of the planned work. Personnel were admonished to remember to take the time to do their job correctly, which includes doing it safely. All of these steps, taken to reduce beam losses and dose to personnel, are important measures to maintain doses as low as reasonably achievable (ALARA). It is inevitable that this shutdown will result in some exposures but the work being done should pay dividends in the reduction of future doses to personnel. (Submitted by Kamran Vaziri.)
It is well known that the Tevatron Collider Run II silicon vertex detector (SVX-II) in the Collider Detector at Fermilab (CDF) would eventually have to be replaced due to radiation damage. In order to anticipate when replacement for the SVX-II is necessary, the experiment needs to know when the sensors and readout chips will no longer provide useful data, which is directly related to the amount of radiation that these devices encounter. Thus, we have conducted dosimetry measurements for the barrel-4 silicon for the CDF 2000 engineering run. This has been done by using in-house thermoluminescent dosimetry (TLD) equipment assigned to the Fermilab Environment, Safety, and Health (ES&H) Section. The TLDs are procured especially for uses of this type and are not those used for routine personnel monitoring. Using TLDs, we measured both the photon and thermal neutron doses at multiple locations surrounding the silicon detectors. Our measurements are in good agreement with damage predictions and will be important for the design of future detectors. There is still work to be done to further quantify the neutron component and the associated energy spectrum. Results of these measurements have been published and further details can be obtained from Susan McGimpsey. (Submitted by Susan McGimpsey.)
As most of our colleagues at U.S. Department of Energy (DOE) Office of Science accelerators know, the possibility of making a transition from self-regulation by DOE to "external regulation" by the U.S. Nuclear Regulatory Commission (NRC) and by the U.S. Department of Labor's Occupational Safety and Health Administration (OSHA) continues to be studied. To that end, short visits to Fermilab by representatives of both agencies were recently made to prepare for more extensive reviews to come later, probably during the autumn. While the eventual regulatory conditions are at present unknown, Fermilab is taking the approach that these outside reviews can be viewed in a positive way by taking advantage of having people not connected with or influenced by DOE practices look at our program from an independent point of view. The main NRC review of Fermilab is now scheduled for mid-November. We can hardly wait! (Submitted by Don Cossairt.)
The United States Particle Accelerator School (USPAS) holds classes for which academic credit can be earned if certain conditions are fulfilled. These sessions are conducted twice yearly at a location near a major research university. Once again, a one-week course entitled "Radiation Physics, Regulation, and Management" will be offered at a session of the USPAS to be held in Madison, Wisconsin, in June 2004. Don Cossairt of Fermilab and Sayed Rokni of Stanford Linear Accelerator Center (SLAC) will be the instructors. In the past, the American Academy of Health Physics (AAHP) has awarded continuing education credits for this course, and those credits have been applied for again for this session. Also of interest to the readers of this newsletter is a related course to be offered the following week entitled "System Safety and Safety Systems for Accelerators" to be taught by Kelly Mahoney and Sandra Prior of Thomas Jefferson National Accelerator Facility (TJNAF). For more information, see the web link for the USPAS. On that web page, one should click on the link for the session in Madison, Wisconsin, for June 21-July 2, 2004. There one can find the details and, in the near future, the link to the necessary application forms. It should be noted that the fees for these courses are low compared to those charged for commercially offered courses of similar duration and intensity. Other courses taught at the USPAS provide an excellent opportunity for personnel involved in radiation protection at accelerators to learn more about the accelerators themselves. Madison, a vibrant university town, is generally a nice place to be at that time of the year. (Submitted by Don Cossairt.)