Bulletin #07 October 29, 1999 _/ _/ _/ _/_/_/_/ _/_/_/_/ _/_/ _/_/ _/_/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/_/_/_/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/_/_/_/ _/_/_/_/ ATOMIC MASS DATA CENTER -------------------------------------------------------------------- I - GENERAL INFORMATION Please see the general information given in bulletin #01. To retrieve one or more of the documents or files available on the AMDC, connect to the AMDC by anonymous-ftp: ftp csnftp.in2p3.fr cd pub/AMDC get document.list or access to the AMDC Web: http://csnwww.in2p3.fr/amdc/ "document.list" is the comprehensive list of documents and files available from AMDC. The AMDC bulletin is sent electronically 2 to 4 times per year. To subscribe / unsubscribe please send an email to: audi@csnsm.in2p3.fr II - NEWS FROM THE EVALUATIONS The most recently published evaluations are AME'95 and NUBASE'97. For consistency it was decided to have the masses in NUBASE'97 exactly as in AME'95. In the future it is planned to have the AME and the NUBASE evaluations published together, the first time in a year from now. Such a publication is urgently needed, because of the impressive number of new results that were published since AME'95 and NUBASE'97. Complementary information is given at the AMDC as file "masstables/santafe.ps". III - NEWS FROM EXPERIMENTS ON MASSES Clark University & Yale beta-gammas / Daeg Brenner October 1999 The Clark University Nuclear Structure Laboratory, in cooperation with colleagues at the Yale University Wright Nuclear Structure Laboratory, has begun a program to measure masses of neutron deficient nuclides which lie near the rp-process path. The classic technique of beta-gamma coincidence spectroscopy is used, augmented with a moving tape collector. State-of-the-art Ge clover gamma-ray detectors combined with a single plastic scintillator beta detector are used for these measurements. Recent results can be found at AMDC "experimental/brenner.doc(.ps)" or by contacting dbrenner@clarku.edu New Results at SPEG / F. Sarazin October 1999 A mass measurement experiment by a time of flight method around N=28 (Z<20) with the SPEG spectrometer at GANIL has brought some new and decisive observations to understand the weakening of the N=28 shell closure. More than 30 masses have been obtained in the region of interest, 8 of them for the first time. The analysis shows clearly the existence of a pseudo-shell closure at N=26. The evidence of a new isomeric state in 43S is corroborated by a shell model calculation. The vanishing of the N=28 shell closure appears to be mainly due to deformation effects and shape coexistence. For further information, please contact: sarazin@ganil.fr The MISTRAL experiment / C. Thibault October 1999 In 1998 and 1999 we measured masses produced by ISOLDE: 23-30Na, 27Al, 25-26Ne, 25-27Mg, 29-32Mg, 30Al, 39K, 41-47K, 46-48Ca and 47-48Ti. The reproducibility of the measurements from run to run determined the accuracy of each individual measurement to be 8.10^-7 while the uncertainties from statistics were typically around 2-3.10^-7. Final accuracies stand between 10 and 20 keV. In the case of 30Na (half-life: 48 ms), the obtained uncertainty is about 1 order of magnitude better than previous ones. The value obtained for 30Na is in agreement with 3 of the values used in AME'95, but corresponds to a more tightly bound nucleus than measured by TOFI in 1991. These results are part of C. Toader's thesis (Orsay, July 16, 1999, soon available at the AMDC as file "experimental/toader.doc.zip" 1.6Mb), and a paper is in preparation. More news on this experiment is available at: http://csnwww.in2p3.fr/massatom/mistrpres_en.html The ESR Schottky experiment / T. Radon October 1999 A novel method for direct, high precision mass measurements of relativistic exotic nuclei has been successfully applied in the storage ring ESR at GSI. The nuclei of interest were produced by projectile fragmentation of 930 MeV/u bismuth ions, separated in-flight by the fragment separator FRS, stored and cooled in the ESR. The mass values have been deduced from the revolution frequencies of the coasting cooled ions. We have measured 115 new mass values with a precision of about 100 keV and a resolving power of 350000 for the neutron-deficient isotopes of the elements 56