An Absorbed Dose Water Calorimeter: Theory, Design, and Performance
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چکیده
منابع مشابه
An Absorbed Dose Water Calorimeter: Theory, Design, and Performance
Two calibrated thermistors sandwiched between two insulative polyethylene films were immersed in a 30 cm cube of water having a low thermal diffusivity. The product of the specific heat of water and temperature rise gave the combined effect of the local absorbed dose and any heat defect at a position along a temperature profile produced by cobalt-60 irradiation. The dose rate was near 18 mGy/s ...
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National Institute of Standards and Technology, Gaithersburg, MD 20899-0001 The NIST sealed water calorimeter is intended for direct measurement of absorbed dose to water. This calorimeter was used for a series of approximately 3700 measurements to investigate the so-called heat defect, that is, anomalous endothermic or exothermic effects caused by dissolved gases. The three systems investigate...
متن کاملAbsorbed dose to water reference dosimetry using solid phantoms in the context of absorbed-dose protocols.
For reasons of phantom material reproducibility, the absorbed dose protocols of the American Association of Physicists in Medicine (AAPM) (TG-51) and the International Atomic Energy Agency (IAEA) (TRS-398) have made the use of liquid water as a phantom material for reference dosimetry mandatory. In this work we provide a formal framework for the measurement of absorbed dose to water using ioniz...
متن کاملComments on 'Converting absorbed dose to medium to absorbed dose to water for Monte Carlo based photon beam dose calculations'.
Current clinical experience in radiation therapy is based upon dose computations that report the absorbed dose to water, even though the patient is not made of water but of many different types of tissue. While Monte Carlo dose calculation algorithms have the potential for higher dose accuracy, they usually transport particles in and compute the absorbed dose to the patient media such as soft t...
متن کاملThe Graphite Calorimeter as a Standard of Absorbed Dose for Cobalt-60 Gamma Radiation
Absorbed dose to water in a cobalt-60 gamma-ray beam has been determined using a thick-walled graphite ionization chamber. The chamber was calibrated in a graphite phantom against a graphite calorimeter, and the graphite calibration factor was converted to a water calibration factor using published energy absorption coefficient ratios and a measured replacement factor. Comparisons between the g...
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ژورنال
عنوان ژورنال: Journal of Research of the National Bureau of Standards
سال: 1982
ISSN: 0160-1741
DOI: 10.6028/jres.087.016