The radiation protection community at Fermilab is presently busy with the conclusion of the current fixed target physics run. At the conclusion of this operational period, there will be a lengthy shutdown during which the historic Main Ring conventional accelerator will be removed from the same enclosure that houses the superconducting Tevatron. When operations resume with the Tevatron, the new Main Injector, separately housed, will supply the protons. The Main Injector will produce roughly 10 times the proton intensity of the present Main Ring. At present, several important radiation measurements are being made to properly address the control and shielding of these higher intensity beams. The current 800 GeV fixed target run has required a large number of special radiation measurements to support it. As it draws to a close, the number and complexity of these measurements have continued as it is recognized that this is the last chance to operate some beams for quite some time and data is needed to support future improvements in the shielding.
During the present run, Fermilab has decided to revisit the adequacy of its program and methodology for protecting groundwater resources against radioactivation. The Laboratory Director at Fermilab has always had a keen interest in this issue. This interest has recently led the Director to appoint several committees consisting of physicists, engineers, and radiation safety professionals to review both the design of the various beam absorbers and their operational histories. This "work in progress" is already leading to some lessons-learned that should eventually result in improved shielding designs and in better operational procedures to monitor and control the beams. We are in the process of carefully reviewing our methods for calculating the shielding of our beam absorbers and are critically questioning our assumptions. Some of these lessons-learned may well prove to be of interest to the larger community.
The PET RFQ (Positron Emission Tomography Radiofrequency Quadrupole) accelerator at Fermilab was used for some preliminary radiochemistry studies. Beam currents were low and thus the total collective dose equivalent was easily kept small. At Fermilab, the building housing the accelerator is surrounded by concrete blocks. This will not be the case when the accelerator is relocated in Louisiana. Studies are being undertaken now to determine how to effectively shield the accelerator in Louisiana.
Recently, Fermilab's activation analysis laboratory achieved a perfect score in the U. S. Department of Energy's quality assurance program administered by the DOE Environmental Measurements Laboratory. In addition to the routine analysis of a variety of samples containing radionuclides, this facility also provides support for the beam flux measurements used to calibrate the beam monitoring equipment and in some cases provides the absolute normalization of beam intensity. During the present run, we have also provided hundreds of special-use TLDs in order to support the physics research program. These TLDs are used to measure radiation levels in the high energy physics apparatus in order to monitor potential radiation damage to key components of the experiments which Fermilab hosts. The radioactive source program has now been improved so that source users can find data concerning the various radionuclides we have available as well as their present status with respect to our training requirements on an internally available World Wide Web page.
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