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Workshop on cosmic ray and high energy gamma ray experiments for the space station era
472
CONFERENCE REPORTS
phase of the Interlaboratory Comparison Project. The main problem is the selection of an appropriately stable trapped electron signal from the eight or so which have been observed by the different groups. Several papers reported on procedures to improve reproducibility of the selected signal such as restricted grain size, organic content, etching, thermal annealing and measurement below room temperature (e.g. De Canni&e et al. (Universit6 Catholique de Louvain-la-Neuve, Belgium), Smith et al. (University of Leicester, UK), Wieser et al. (Neuherberg) and Yokoyama (Gif-sur-Yvette). In spite of these difficulties several attempts have been made to obtain dates for shells and bones because of their great importance for archaeologists and Quaternary geologists. Apart from the difficulties in selecting an appropriate signal to determine the equivalent dose, dating is complicated by assumptions concerning the annual doserate. Radtke et al. (Universit/it Dfisseldorf, W. Germany) reported that for one species of marine shell, Glrc#neris, the uranium content was a function of depth below the shell surface. The shell appeared to be a closed system since both uranium series and ESR ages on the inner and outer parts of the shell were in agreement with each other. Another shell, C e r a s t o d e r m a , was considered unsuitable for dating because the uranium content was thought to have varied with time. Bones are also likely to experience changes in their uranium content during the burial period, but interfering signals from organic radicals were shown to be a major problem by Sales et al. (University of Leicester).
Enamel from teeth seems to have a much greater potential for ESR dating, Griin and lnvernati (Universitfit K61n, W. Germany) reported on a wellresolved, radiation-sensitive ESR signal for hydroxyapatite in enamel. The signal is sufficiently stable to allow dating up to 1 Myr, has a high saturation level, and is unaffected by either grinding or light. These findings were supported by similar evidence presented by Schwarcz (McMaster llniversity, Hamilton. Canada). Once again, some problems are caused b> the uptake of uranium during burial. Both authors discussed the difficulties in beta dosimetry on account of the high accumulation of uranium in the dentine and cementum which surround the enamel. This Fourth Specialist Seminar on TL and ESR Dating was judged to be a great success by all those attending. The organisers, Professor G. A. Wagner and Dr E. Pernicka (Max-Planck-lnstitut f/,ir Kernphysik, Heidelberg, W. Germany), and Dr M. Grfinewald (Museum der Stadt Worms) were congratulated not just lk~r the smooth running of the meeting but also l\~r the organization of an exciting social programme which ~aried from an aweinspiring and mouth-watering buffet at a local castle to a wine-tasting at a vineyard overloooking the Rhine valley and an organ-recital at the Liebrauenkirche on the outskirts of Worms. Groups of delegates continued TL and ESR discussions whilst enjoying the local beer, wine and food often late into the night, and the camaraderie experienced at the meeting will linger in my memory f o r a long time. The Fifth Seminar will be held in King's College, Cambridge, UK, from 6 10 July 1987.
W O R K S H O P ON C O S M I C RAY A N D H I G H E N E R G Y G A M M A RAY E X P E R I M E N T S FOR THE SPACE S T A T I O N ERA Louisiana State University, U.S.A., 17 20 Octobcr 1984 DENIS O'SULLIVAN
School of Cosmic Physics. Institute of" Adwmced Studies, Dublin, Republic of Ireland TIlE MH~TINC;was held at Louisiana State University, Baton Rouge, from 17th to 20th October 1984 and ~as attended by more than a hundred delegates.
C O N F E R E N C E REPORTS
473
The opening talk which was to be given by Carlo Rubbia was cancelled and D. Cline of the University of Wisconsin substituted with some ideas on the search for supersymmetric particles in the space station era. The NASA director for the Space Station, Bill Raney, then covered the general aspects of the proposed programme along with the estimated costs of development. Funding will commence in the financial year 1987, and the cost of the initial capability will be ~-US$8 billion. It is expected that the first stage will be in orbit by 1993. Further general talks included one by a representative of Martin-Marietta Aerospace on possible uses of the Shuttle external tank as a craft for in-orbit applications. (At present the procedure is to jettison it and allow it burn up in the atmosphere). The remainder of the workshop dealt witk specific topics such as the search for anti-particles, high energy nuclear interactions, nuclear composition, Shuttle experiments, high energy gamma rays and a general look at space station facilities and detectors. The anti-particle session included some considerations of how space station experiments could be used to search for dark matter in the universe. Nuclear composition studies in the ultra heavy region were the subject of a talk by J. Waddington who also proposed the use of a large spherical cerenkov detector of up to 100 m 2 ster geometric factor. The gamma-ray session dealt mainly with an outline of the history of the field and the hopes and expectations for the Gamma Ray Observatory which is due to be launched in 1988. The mission will include experiments on high energy gamma-rays, nuclear gamma-rays and gamma-ray bursts. Possible extensions of these studies for the space station era were discussed. Solid state nuclear track detectors were well represented with papers by the Berkeley, Dublin, Louisiana, Michigan, Tara, Washington and other groups. Many of these papers dealt with the study of cosmic ray charge and energy spectra using the LDEF, Spacelab and Space Shuttle facilities. Overall, it was an exciting workshop with plenty of opportunities for discussing new ways of tackling the many outstanding problems in astrophysics. However, it was generally felt that delegates were too ready to propose old experiments, scaled up by a factor of ten or a hundred, instead of thinking afresh for the space station era. Despite this criticism I have no doubt that the meeting was fruitful and will be considered a significant milestone when that era dawns.
CONFERENCE REPORTS
phase of the Interlaboratory Comparison Project. The main problem is the selection of an appropriately stable trapped electron signal from the eight or so which have been observed by the different groups. Several papers reported on procedures to improve reproducibility of the selected signal such as restricted grain size, organic content, etching, thermal annealing and measurement below room temperature (e.g. De Canni&e et al. (Universit6 Catholique de Louvain-la-Neuve, Belgium), Smith et al. (University of Leicester, UK), Wieser et al. (Neuherberg) and Yokoyama (Gif-sur-Yvette). In spite of these difficulties several attempts have been made to obtain dates for shells and bones because of their great importance for archaeologists and Quaternary geologists. Apart from the difficulties in selecting an appropriate signal to determine the equivalent dose, dating is complicated by assumptions concerning the annual doserate. Radtke et al. (Universit/it Dfisseldorf, W. Germany) reported that for one species of marine shell, Glrc#neris, the uranium content was a function of depth below the shell surface. The shell appeared to be a closed system since both uranium series and ESR ages on the inner and outer parts of the shell were in agreement with each other. Another shell, C e r a s t o d e r m a , was considered unsuitable for dating because the uranium content was thought to have varied with time. Bones are also likely to experience changes in their uranium content during the burial period, but interfering signals from organic radicals were shown to be a major problem by Sales et al. (University of Leicester).
Enamel from teeth seems to have a much greater potential for ESR dating, Griin and lnvernati (Universitfit K61n, W. Germany) reported on a wellresolved, radiation-sensitive ESR signal for hydroxyapatite in enamel. The signal is sufficiently stable to allow dating up to 1 Myr, has a high saturation level, and is unaffected by either grinding or light. These findings were supported by similar evidence presented by Schwarcz (McMaster llniversity, Hamilton. Canada). Once again, some problems are caused b> the uptake of uranium during burial. Both authors discussed the difficulties in beta dosimetry on account of the high accumulation of uranium in the dentine and cementum which surround the enamel. This Fourth Specialist Seminar on TL and ESR Dating was judged to be a great success by all those attending. The organisers, Professor G. A. Wagner and Dr E. Pernicka (Max-Planck-lnstitut f/,ir Kernphysik, Heidelberg, W. Germany), and Dr M. Grfinewald (Museum der Stadt Worms) were congratulated not just lk~r the smooth running of the meeting but also l\~r the organization of an exciting social programme which ~aried from an aweinspiring and mouth-watering buffet at a local castle to a wine-tasting at a vineyard overloooking the Rhine valley and an organ-recital at the Liebrauenkirche on the outskirts of Worms. Groups of delegates continued TL and ESR discussions whilst enjoying the local beer, wine and food often late into the night, and the camaraderie experienced at the meeting will linger in my memory f o r a long time. The Fifth Seminar will be held in King's College, Cambridge, UK, from 6 10 July 1987.
W O R K S H O P ON C O S M I C RAY A N D H I G H E N E R G Y G A M M A RAY E X P E R I M E N T S FOR THE SPACE S T A T I O N ERA Louisiana State University, U.S.A., 17 20 Octobcr 1984 DENIS O'SULLIVAN
School of Cosmic Physics. Institute of" Adwmced Studies, Dublin, Republic of Ireland TIlE MH~TINC;was held at Louisiana State University, Baton Rouge, from 17th to 20th October 1984 and ~as attended by more than a hundred delegates.
C O N F E R E N C E REPORTS
473
The opening talk which was to be given by Carlo Rubbia was cancelled and D. Cline of the University of Wisconsin substituted with some ideas on the search for supersymmetric particles in the space station era. The NASA director for the Space Station, Bill Raney, then covered the general aspects of the proposed programme along with the estimated costs of development. Funding will commence in the financial year 1987, and the cost of the initial capability will be ~-US$8 billion. It is expected that the first stage will be in orbit by 1993. Further general talks included one by a representative of Martin-Marietta Aerospace on possible uses of the Shuttle external tank as a craft for in-orbit applications. (At present the procedure is to jettison it and allow it burn up in the atmosphere). The remainder of the workshop dealt witk specific topics such as the search for anti-particles, high energy nuclear interactions, nuclear composition, Shuttle experiments, high energy gamma rays and a general look at space station facilities and detectors. The anti-particle session included some considerations of how space station experiments could be used to search for dark matter in the universe. Nuclear composition studies in the ultra heavy region were the subject of a talk by J. Waddington who also proposed the use of a large spherical cerenkov detector of up to 100 m 2 ster geometric factor. The gamma-ray session dealt mainly with an outline of the history of the field and the hopes and expectations for the Gamma Ray Observatory which is due to be launched in 1988. The mission will include experiments on high energy gamma-rays, nuclear gamma-rays and gamma-ray bursts. Possible extensions of these studies for the space station era were discussed. Solid state nuclear track detectors were well represented with papers by the Berkeley, Dublin, Louisiana, Michigan, Tara, Washington and other groups. Many of these papers dealt with the study of cosmic ray charge and energy spectra using the LDEF, Spacelab and Space Shuttle facilities. Overall, it was an exciting workshop with plenty of opportunities for discussing new ways of tackling the many outstanding problems in astrophysics. However, it was generally felt that delegates were too ready to propose old experiments, scaled up by a factor of ten or a hundred, instead of thinking afresh for the space station era. Despite this criticism I have no doubt that the meeting was fruitful and will be considered a significant milestone when that era dawns.