Determination of the secondary electron equilibrium using an extrapolation chamber
To ensure that the external personnel dosimetry program conducted by U. S. Department of Energy (DOE) contractors is of the highest quality, the DOE established the Department of Energy Laboratory Accreditation Program or DOELAP. The contractor`s dosimetry program is assessed against the criteria set forth for dosimeter performance and the associated quality assurance and calibration programs. Although personnel dosimeters are not processed or calibrated by Fermilab, a proactive quality assurance program is in place to ensure accurate monitoring. This program includes quarterly blind testing of the dosimeters used by personnel. During the on-site assessment conducted of Fermilab`s external dosimetry program during May 1994, an observation with regard to equipment maintenance and calibration was made: ``calibration personnel should probably review the electron secondary equilibrium needs at various irradiation distances from the {sup 137}Cs irradiation systems`` The majority of the secondary electrons are generated through interactions of the beam with the collimator. Secondary electrons increase the low energy component of the radiation field, increasing the shallow doses measured. For dosimetric purposes, this increase needs to be defined so appropriate corrections to calculations or modifications to the facility can be made. Prompted by this observation, a study was designed to investigate the electron secondary equilibrium in the facility used for the blind testing by determining the dose equivalent as a function of depth in a tissue-equivalent medium. This presentation summarizes the methodology utilized and results of the investigation.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- AC02-76CH03000
- OSTI ID:
- 412176
- Report Number(s):
- FNAL/C-96/318; CONF-970134-1; ON: DE96050562; TRN: 97:001152
- Resource Relation:
- Conference: 30. midyear topical meeting of the Health Physics Society, San Jose, CA (United States), 5-8 Jan 1997; Other Information: PBD: Sep 1996
- Country of Publication:
- United States
- Language:
- English
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