#01 November 30, 1995 _/ _/ _/ _/_/_/_/ _/_/_/_/ _/_/ _/_/ _/_/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/_/_/_/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/_/_/_/ _/_/_/_/ ATOMIC MASS DATA CENTER ------------------------------------------------------------ I - GENERAL INFORMATION The CSNSM has the pleasure to announce an on-line Data Center dedicated to Atomic Masses. The main goal of AMDC is to give progress reports on the evaluation of masses and to put at the user's disposal the most recent data: Ame'95 is already documented (see II). The NUBASE database and the NUCLEUS pc-program, when completed, will also be distributed through AMDC. Furthermore, we propose that AMDC and the bulletin be a place where information on masses can be exchanged. All those working on topics related to atomic masses could keep the community informed, in a non-official way, on the latest developments of their work, whether experimental or theoretical. As an example, this first AMDC bulletin gives some news from our laboratory. We indeed hope that next issues will distribute news from YOUR work. The AMDC bulletin itself would benefit from being brief. It is therefore suggested to present in it short news that could, if desired, refer to more detailed documents (ascii or postscript) that will be added to the database (see e.g. III and the refered postscript document) To retreive one or more of the documents or files quoted below, connect to the AMDC by anonymous-ftp. Example: ftp csn-hp.in2p3.fr user: anonymous password: your electronic address cd pub cd AMDC (please type AMDC in capitals) get readme.mas95 get mass_rmd.mas95 quit II - NEWS FROM THE ATOMIC MASS EVALUATION ------------------------------------------------- | "THE 1995 UPDATE TO THE ATOMIC MASS EVALUATION" | | (Ame'95) | | by G. Audi and A.H. Wapstra | | | | Nuclear Physics A595 (1995) 409-480. | | (December 25, 1995) | ------------------------------------------------- The first update of the Atomic Mass Evaluation (Ame'95) is with the printer. A preprint of the accompanying text is available as "ame95.ps" from the AMDC. Six files resulting from the evaluation are also in AMDC: mass_rmd.mas95 Recommended masses rct1_rmd.mas95 Recommended reaction energies, table 1 rct2_rmd.mas95 Recommended reaction energies, table 2 mass_exp.mas95 Experimental masses rct1_exp.mas95 Experimental reaction energies, table 1 rct2_exp.mas95 Experimental reaction energies, table 2 their description is given in "readme.mas95" III - NEWS FROM EXPERIMENTS ON MASSES The MISTRAL experiment / M. de Saint Simon Nov 95 The adaptation of the RF spectrometer to atomic mass measurements is under way at Orsay. The re-designed RF system will be tested in December. Optimization of the beam transmission and the mass resolving power should start in February 1996. A brief status report on the MISTRAL experiment is available from the AMDC as a PostScript file "mistral01.ps" IV - NEWS FROM THE THEORETICAL MASSES Pairing in nuclear mass calculations / Duflo-Zuker Nov 95 The contribution of pairing energy to the nuclear masses is relatively important (2 MeV difference between even-even and odd-odd nuclides in the region of lead). It is well taken into account for almost all nuclides by a term varying as A^(-1/3). But this correction is insufficient for the very light masses (A<20). We show that with only 2 terms varying in A^(-4/3), one for the even N=Z nuclides, and one for the odd N-even Z with N>Z (and symmetrically, even N-odd Z with N