RADIATION SAFETY AT THE NSLS

Introduction:

Radiation safety requirements for activities conducted at NSLS are defined in the BNL Radiological Control Manual and in internal NSLS requirements defined in this section of the PRM. When planning your work at NSLS, it is important that these requirements be properly addressed. BNL regulations are subject to Federal enforcement under the Price Anderson Act. In the recent past, serious single violations or repeated minor violations have resulted in substantial fines being paid by BNL. Individuals responsible for these violations are subject to disciplinary actions. Be sure that you understand what is expected during your work at NSLS. Contact a member of the NSLS Safety Staff whenever you have a question or need help.

Radiation Exposure:

• Ionizing radiation produced during operation of the Light Source consists mainly of high-energy Bremsstrahlung radiation and neutrons from the storage rings and injector, and x-ray synchrotron radiation from the X-Ray Ring. Lead and concrete shielding around the injector and storage rings and along the beamlines provide protection against photons and neutrons. This shielding may be removed or modified only with prior specific permission from the NSLS Safety Officer, and then only after the beamline or accelerator has been locked out so there can be no radiation exposure (Also see Safety System Work Authorization - PRM 3.4.1b).
• Radiation exposure to personnel working on the NSLS floor is quite low. Most personnel do not receive recordable doses as determined by BNL TLD radiation badges. Despite the low doses, personnel are expected to wear radiation badges whenever they are within the Controlled Areas of NSLS. In addition, in order to maintain radiation exposures as low as reasonably achievable (ALARA), personnel in the vicinity of VUV ring are asked to stand clear of certain areas during machine injection or special study periods. Personnel needing access to these areas will likely require additional training. Personnel must not enter a posted "Radiation Area" when radiation is present without a radiation work permit (Also see RWP PRM 3.4.1a).

Beam-line Radiation Protection:

• The energy spectrum of the synchrotron radiation in most X-Ray Ring beamlines extends to a few tens of kilovolts; a thin layer of lead and steel is usually an adequate shield against scattered radiation. However, the radiation intensity directly in the photon beam is extremely high. Any exposure to the beam would result in instant serious injury to the portion of the body exposed. Therefore, personnel access to the beam is strictly forbidden and controlled. Where appropriate, beam pipe flanges are secured with padlocks that can only be opened with keys that are part of the interlock system to protect against inadvertent access to the synchrotron beam.
• The hutches enclosing the experiments have personnel interlocks to allow access to the equipment and samples and yet prevent exposure to the synchrotron radiation. Once an experiment is set up, the user can operate these interlock systems, with little intervention from the operations staff. The personnel safety of beam line users at the Light Source depends on adherence to the operational procedures for accessing the hutches and on the integrity of the personnel interlock systems. Modification and maintenance work on these systems is rigidly controlled and monitored. Contact the NSLS Safety Officer or a NSLS Operations Coordinator if you have questions.

Radioactive Material and Sources:

• Radioactive material or contamination is normally not a significant factor at the NSLS. Material activation produced by machine operations is primarily limited to components of the NSLS vacuum system directly exposed to the electron beam. However, all material removed from the storage rings and injector must be surveyed prior to release to ensure that radioactive components are labeled and controlled properly. Contact the NSLS ESH Facility Representative for surveys.
• Radioactive materials used at the NSLS as part of a research or operational program must be utilized in conformance with the BNL Radiological Control Manual. Any radioactive materials brought to the NSLS must be identified in the initial Experiment Safety Approval Form. All such material must be labeled and controlled as specified in the Manual. Operating procedures and radiation work permits may also be required. Sealed sources must be entered into the NSLS inventory and a Source Custodian established. Additional training will likely be necessary for responsible personnel. Contact any member of the NSLS ESH Staff if you have questions.

 

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John Aloi (aloi@bnl.gov) maintains this document. . . . . DISCLAIMERS : Revised Date : July 26, 1999