Minutes of the Third GSUF Meeting
27 November 2000
National Physical Laboratory
| Participants: | Fiona Barr | British Energy, Hunterston B | |
| Michel Ceuppens | Canberra Packard, Belgium | ||
| Peter Danyluk | AWE Aldermaston | ||
| Julian Dean | NPL | ||
| Tony Dell | VLA | ||
| Jim Desmond | BNFL Geoffrey Schofield Laboratories | ||
| Mike Dolan | AWE Aldermaston | ||
| Steve Dunkley | Harwell Instruments | ||
| Trevor Hatt | Perkin Elmer | ||
| Elizabeth Howie | British Energy, Hunterston B | ||
| Simon Jerome | NPL | ||
| Satwant Johal | NPL | ||
| Elisabeth Jones | University Hospital of Wales | ||
| Steven Judge | AEA Technology QSA | ||
| John Lees | BNFL Magnox | ||
| Andrea Lewis | NNC WQCL | ||
| Richard Lukey | VLA | ||
| Bob Major | NNC | ||
| John Makepeace | NPL (Chairman) | ||
| Fiona Miller | UKAEA Dounreay | ||
| Andy Pearce | NPL | ||
| Martin Phillips | BNFL Berkeley | ||
| Calvert Pratt | BNFL Berkeley | ||
| Anne Ross | UKAEA Dounreay | ||
| Martin Rushby | AWE Aldermaston | ||
| Bob Sharrock | Urenco | ||
| Matthew Simpson | DERA RPS | ||
| Robin Treadwell | AWE Aldermaston | ||
| Tim Twomey | Perkin Elmer | ||
| Stephanie Vallet | Harwell Instruments | ||
| Doug Van Cleef | Perkin Elmer | ||
| Steve Waters | MRC Clinical Sciences Centre | ||
| Mike Woods | NPL | ||
| Simon Woods | NPL (Secretary) | ||
| Mike Youngman | NRPB |
1. Chairman’s opening remarks
The Chairman welcomed those present. He noted that this was an extraordinary meeting of the forum in that NMSPU funding only covered two meetings of the GSUF. In the forthcoming new three year programme, annual meetings were planned.
2. Minutes of the 2nd meeting – 29 October 1999
These were accepted without correction.
3. Matters arising from the minutes
Action 2.1: Simon Woods/Ian Adsley to discuss (use of AEAT decay data) with interested parties to agree a suitable format.
Discussions ensued as to the suitability of this approach. Opinion was split between users’ with some not wanting an alterable database whilst others preferred an easy load format. Mike Woods commented that there needs to be one agreed data set and that it should be agreed internationally. The current evaluation work being undertaken by an IAEA CRP will be accepted as authorative, but it comprises a limited set of data.
The Radiochemical Manual data itself is “owned” by AEA Technology with funding provided from the DTI through NMSPU. If this data were to be used, the legality of such a step would have to be checked with both parties.
Further discussion of nuclear decay data was deferred to later on the agenda.
Action 2.1a: All: Inform Simon Woods of any Millenium Compliance problems experienced for dissemination.
No problems reported. Action completed.
Action 2.2: NPL (Simon Woods) to devise and distribute a questionnaire on user requirements for intercomparisons.
Action 2.3: NPL (Simon Woods) to devise and distribute questionnaire to determine problems with low energy gamma-ray measurements.
These actions were deferred to later in the agenda.
Action 2.4: All to send any comments on the (MDA) subgroup proposals to Simon Woods by end of December.
Only one response has been received. Results of the working group will be redistributed with the current minutes to stimulate discussion. It was suggested that participants in the environmental intercomparison be asked to report MDAs. For the MDAs, participants should not be worried about the slight difference between 95% CL and k=2.
Action 2.5: NPL (Simon Woods) to gauge amount of interest in proposed meetings (with manufacturers), which manufacturers to target and identify topics for discussion.
Harwell Instruments and EG&G both present at the forum and had agreed to give presentations (see later).
Action 2.6: All to submit any data they may have on this (226Ra 186 keV) transition to Simon Woods.
Two user responses received. Simon Woods will give a short presentation on the apparent resolution of the problem later in the forum.
Action 2.7: NPL (John Makepeace) to investigate the possible funding of a third meeting of the GSUF within the current NMSPU Ionising Radiation programme.
This forum. NMSPU have agreed to the principle that the minimum should be at least once a year. Action completed.
4. User discussion
4.1 226Ra
Simon Woods gave a short presentation detailing a new measurement of the alpha branching ratios reported at the MARC V conference in Hawaii. From these data, a gamma-ray emission probability for the 186 keV transition of 0.0364(4) may be derived, in agreement with directly determined values (which previously deviated by 9% from values derived from decay scheme balances).
It was noted that Alan Nichols (Harwell) was in the process of undertaking a re-evaluation of this radionuclide as part of the Decay Data Evaluation Project. This new evaluation will be public domain.
4.2 Propagation of uncertainties in detection limits
Many users consider only statistical uncertainties and ignore any systematic components. An accepted method of propagation needs to be defined.
Michel Ceuppens (Canberra Packard, Belgium) informed the forum that their software takes systematic uncertainties from the efficiency curve, but uncertainties in positioning and density are not taken into account. Consequently, a user will need to increase any reported MDA, estimated from the sample background, to compensate for this.
In a similar vein, Doug van Cleef (Perkin Elmer, USA) commented that the principal component to an MDA is the background uncertainty. If numerous measurements of blanks are taken, this will include uncertainties, such as positioning, in an empirical manner. A single measurement is not ideal. Other uncertainties may be propagated by normal methods.
NPL does run courses on uncertainties. What most users require is a body to examine, identify and quantify all uncertainties, with national laboratories disseminating the methods. It was suggested that a sub-meeting of the GSUF be held to consider this topic.
| Interested members: | Bob Sharrock |
| Matthew Simpson | |
| Richard Lukey | |
| Steve Judge | |
| Mike Youngman | |
| Tony Ware | |
| Bob Major |
Tony Ware commented that the Chemistry Commission has also raised this topic.
4.3 ISO 9000:2000
The forum members were generally happy with this accreditation system. The majority of those present were covered for QA; 1/3 through ISO and 2/3 through UKAS.
4.4 Questionnaires
Members of the forum suggested a number of additions to the questionnaires relating to actions 2.2 and 2.3. These suggestions will be incorporated into the documents and the forms distributed to all interested parties, preferably as Word 6 documents.
Action 3.1: NPL (Simon Woods) to amend and distribute questionnaires.
4.5 Radionuclide decay data libraries
It was suggested that a “cut and paste” format could be the way forward, but some participants were worried about validating such a format. There needs to be fields to identify references and alteration dates. The manufacturers present indicated that they were amenable to this idea.
There is a strong requirement for an international body to agree upon a data set. It was suggested that an appropriate assembly might be ICRM.
5. Manufacturers’ presentations
5.1 Michel Ceuppens (Canberra Packard)
| Topics: | Genie 2000 v2.0 |
| TCS theory | |
| ISOCS/LABSOCS | |
| Traceability |
5.2 Doug van Cleef / Tim Twomey (Perkin Elmer)
| Topics: | X-Cooler |
| Detector configurations | |
| DigiDART | |
| SMART 1 HPGe | |
| GammaVision 5.2 | |
| Isotopic |
6. Concluding discussions
It was noted that the IRMF maintain a register of people providing services, primarily commercial but also internal. It was felt that the GSUF should follow this route.
Action 3.2: NPL (Simon Woods) to devise and distribute a suitable questionnaire
It was noted that information would only be made available for dissemination with the express permission of the service provider.
Simon Woods
Secretary, GSUF