----------------------------------------------------- ALMA Science Advisory Committee Teleconference, 4 December 2002 Draft Minutes Participants: R. Bachiller, A. Benz, G. Blake, L. Bronfman, P. Cox, R. Crutcher, N. Evans, S. Guilloteau, M. Gurwell, T. Hasegawa, M. Ishiguro, R. Kawabe, J. Mangum, D. Mardones, J. Richer, S. Sakamoto, P. Schilke, P. Shaver, P. Vanden Bout, E. van Dishoeck, D. Wilner, C. Wilson, A. Wootten, S. Yamamoto The proposed agenda was adopted, and the minutes of the last teleconference were accepted. 1) Status Report P. Vanden Bout reported on the activities of the JAO. There have been many meetings, and the project plan and budget are being updated. He reported briefly on the ACC telecon on 3 December; it is an important time at the moment, as the State Dept. is nearing the conclusion of its work, and the Bilateral Agreement is coming up. At a PR telecon on 3 December a number of items were discussed, to be shared between the two partners: a video, a brochure, a logo, the website, and a PR plan. There were no new developments on Chile. G. Mangum reported on the acceptance plan for the Vertex antenna. Tentative dates are 13-22 December, but may slip. The surface is presently 75 micron rms. P. Vanden Bout reported that the Alcatel antenna is progressing quite well. 2) Reports from Recent Backend and Frontend Reviews Concerning LOs, A. Wootten said that various options had been discussed. Tests will take place over the next few months, leading to a decision. A report on the review is being prepared. S. Guilloteau said that it may be difficult to support frequency switching; the ASAC may have to be consulted on this. A. Wootten mentioned the preparation of specs for the frontends. The frontend groups would prefer that the specs be relaxed by 25%. There was some concern regarding the frontend bandwidth. The stability requirement was debated – it is a hard spec to reach. The final input for the specs document is due this week. C. Wilson asked how specs were changed in the Project Book. P. Vanden Bout replied that such changes would come to the JAO, which would consult the ASAC for advice. 3) Proposed correlator upgrade A. Wootten referred to the new memo 441. A possibility is that the ALMA correlator could be improved, based on developments for the EVLA. The number of channels could be increased in wideband mode, from 256 to 8192 channels in 2 GHz; the spectral resolution performance of the system would be increased by factors as high as 32. The increased data rate would be a challenge. The change would mean new boards, and would cost about $0.5 million (which could be covered from contingency). R. Bachiller endorses the plan, saying that it would solve the main limitation of the baseline correlator. A. Wootten said that the 2nd generation correlator would still have a place. C. Wilson said that the ASAC should focus on the science; she will write draft recommendations. 4) Report from Science IPT E. van Dishoeck said that the 8 November meeting had been very successful. She said that, from the community input (at the meeting and via questionnaire), a strong central node was preferred for the Regional Support Center. There were discussions on possible upgrades (e.g. the receiver band priorities). Views and concerns were expressed about software, particularly AIPS++. There was also some discussion on how to attract more young people to the project. The community encouraged more such meetings, perhaps every 1-2 years. The presentations from the meeting are on the website http://www.eso.org/projects/alma/meetings/gar-nov02/ A. Wootten said that a similar meeting will be held in North America in mid 2003. E. van Dishoeck said that the refinement of IPS milestones has continued. The main recent event was the new configuration design, based on a new topology map. Surveyors were presently staking out positions on the site. C. Wilson asked whether more weight was being given to the longer baselines on the Y+ configuration, and this was confirmed by A. Wootten. A. Wootten said that milestones for the calibration group are coming up, and that progress is being made on several fronts, leading up to calibration specifications. C. Wilson said that there are several science examples for calibration; any further examples should be sent to S. Guilloteau. 5) Update on upcoming software IDRs C. Wilson gave an update on the software internal design reviews. She pointed out that relevant documents will shortly be available on the website, and the ASAC liaisons are encouraged to look at them. 6) AIPS++ audit M. Gurwell gave comments on the audit document. C. Wilson pointed out that there was nothing on speed, and that many calibration items remained to be filled in. It was commented that it would be useful to see similar audits of other relevant software packages. A. Wootten said that an internal NRAO technical review of AIPS++ is planned in January. Some ASAC representatives will attend. H said that ASAC members are encouraged to use AIPS++. C. Wilson suggests that ASAC members read the audit document, which will be discussed in the next telecon. 7) Dates of face-to-face meeting and ASAC composition The next face-to-face meeting will take place sometime in the period between 31 March and 17 April, at IRAM in Grenoble. ASAC members were requested to send their constraints on these dates to A. Wootten. C. Wilson said that the ASAC will stay the same until it is re-constituted by the new ALMA Board. 8) Next teleconference The next ASAC teleconference will take place on Wednesday 8 January at 15:30 UT.