Intercomparison of extrapolation chamber measurements of the absorbed dose rate in tissue for beta radiation in the field of radiation protection
Project Description
The beta intercomparison was started in January 2004 at PTB. Because of difficulties with the custom bodies in Russia the VNIIM participation is postpone to the end of the comparison (August/September 2005). The time schedule was revised.
The Technical protocol is accordingly modified.Now the comparison equipment is located at STUK (Finland) and will come back to the PTB in May 2004. The Measuring Protocol of the PTB is almost ready and will be sent separately to the EUROMET TC-IR Chairman in the next days. The beta intercomparison was started in January 2004 at PTB. Because of difficulties with the custom bodies in Russia the VNIIM participation is postpone to the end of the comparison (August/September 2005). The time schedule was revised. The Technical protocol is accordingly modified.Now the comparison equipment is located at STUK (Finland) and will come back to the PTB in May2004. The Measuring Protocol of the PTB is almost ready and will be sent separately to the EUROMET TC-IR Chairman in the next days. The intercomparison will be performed using the absorbed dose rate in 0,07 mm tissue depth for beta radiation as measuring quantity. For beta radiation this quantity is the base for the measurement of the quantities of the directional dose equivalent H’(0.07) and the personal dose equivalent Hp(0.07) in the field of radiation protection.A flat ionisation chamber will be used as transfer chamber. The organization will be star shaped, after each participant measurement the chamber will be send back to the coordinator for constancy checks.. The chamber is combined with a complete measuring system (high voltage supply, electrometer and computer). At the laboratories of the participants the chamber will be calibrated in the beta reference fields of the radio nuclides Pm-147, Kr-85 (and/or Tl-204) and Sr-90/Y-90 at agreed calibration conditions. The calibration factors will be the comparison parameters.The recommendations of the ISO standard ISO 6980 are the base of the comparison measurements and evaluations.
Final Report 2008-02-14
The comparison has been completed and the results are available in the KCDB.
All the reports from the participant were received by the pilot laboratory, the last one by April 2007. The pilot laboratory produced a Draft of the final report which was commented and finally adopted by the participants, by EUROMET, and by the CCRI.
Progress Report 2005-11-16
The beta intercomparison was started in January 2004 at PTB.
5 participants finished their measurements. 4 of them have sent their measuring reports to the PTB.
The partner OMH cancelled the participation on this comparison. The schedule was changed because of unavoidable delays at the transportation of the equipment.
Now the comparison equipment is located at VNIIM (RU) and will come back to the PTB about December 2005.
The completion date of the comparison (final report) will be the end of June 2006.