Malaysian participation in the IAEA/WHO postal TLD and postal ionisation chamber intercomparison programmes: analysis of results obtained during 1985-2008.

During the years 1985-2008, the Secondary Standards Dosimetry Laboratory of Malaysia (SSDL Malaysia) has participated 37 times in the IAEA/WHO intercomparison programmes. This paper reports an analysis of the intercomparison data and demonstrates that the quality of the SSDL calibration service is well within the limits required by IAEA.

Accurate measurement of exposure rate from a 60Co teletherapy source: deviations from the inverse-square law.

A cylindrical gamma-ray 60Co source of activity alpha is predicted to produce an exposure rate X at a distance d in vacuum, given by X = gamma(T)(alpha/d2), where gamma(T) is the specific gamma-ray constant. It has been documented that this formula may be used to approximate X with an accuracy of 1% from a source of length l, provided that d/l > or = 5. It is shown that the formula is accurate to 0.

Absorbed Dose to Water Determination Using IAEA, HPA, NACP, AAPM, NCRP and ICRU Protocols for 1.25 MeV Gamma Ray 6 MV and 10 MV X-Rays: An Intercomparison of Results when IAEA was taken as a Standard Protocol.

Absorbed dose to water was measured with ionisation chambers NE 2561 (#267), NE 2581 (#334), NE 2571 (#1028), using the IAEA standard water phantom. The ionisation chamber was inserted in the water phantom at a reference depth dependent on the type of the radiation quality used. Three radiation qualities were used namely 1.