Science IPT 20 October 2003. Wootten, van Dishoeck, Laing, Conway, Lucas, Jerome, Morita, Hills, Sterling, Mangum, Hasegawa, Tatematsu, Holdaway, Wilson Status of Action Items The telecon opened with a listing of action items on the Science IPT from various recent meetings--our own telecon of last month, mini-ALMA Week, the Correlator CDR and the AMAC meeting. Some of these will require substantial work; many have been satisfied already. The Operations Group has received some input from each of the IPTs and will discuss operations at a telecon on 21 October, in preparation for a report due 2003 Dec 31. Outstanding items include the queries from the draft report of the Correlator CDR: Correlator CDR: "The committee recommends that the Science IPT clarify the conditions under which the spectral dynamic range of 40 dB be required. Since the ALMA correlator is a 2-bit correaltor, the dynamic range can only be achieved if the narrowband power into the receiver is less than a certain small fraction of the total receiver power. The Science IPT must quantify what the maximum total narrowband power is into the receivers, as fraction of the total receiver noise power." "The science specifications indicating what the maximum sensitivity loss of the correlator must be should be further clarified. Nominally, with the European tunable filter card and a 2-bit correlator, the sensitivity loss in the correlator is 1-(0.88 x 0.985)=.133." Some simulations may be needed to determine imaging artifacts possibly caused by phase and amplitude errors in overlap region of tunable filter option for correlator. And a request by the Board to simulate imaging using an array consisting of two different antenna designs, using the designs and specifications for the two prototype antennas as examples. If array were to consist of half of one type and half of the other, what would the demonstrable effect be upon the sciece the array produces? Hills: simulate effect of two different designs which meet the same specifications. What are the realistic differences between the designs. Some things work better owing to common mode cancellations. Project news: Wootten: mini-ALMA Week, Correlator CDR and AMAC meetings have occurred. Several actions on the Science IPT are listed above. The Correlator design meets the science requirements. The two stage tunable filter takes the baseline correlator some way toward fulfulling Second Generation Correlator requirements. We recommend pursuit of the tunable filter design. The Correlator IPT will generate a list of modes available with the tunable filter so that the science IPT can consider the new science possibilities which it will enable. van Dishoeck: Successors appointed. Tom Wilson new EUPS, Robert Laing new EUInstrument Project Scientist. Based at ESO. RL 1 Nov, TW on 18 Nov. This will be Ewine's last Science IPT telecon though she will continue to serve on the ESAC and on the European ALMA Board. Wootten: Thanks to EvD for all of her guidance of the Science IPT. van Dishoeck: AMAC meeting. Presentations will be on almaedm. Overall feedback was that the work done has been enormous and of high quality. Project understaffed, particularly in JAO. They talked about JAO PS position. They will look inside the ALMA organization for interim staffing. Impressed with system engineering work which has been done. Comment on Project Plan also, that changes to this should follow implementation of the plan. Science items--first on the science requirements document but never presented to AMAC. Illustrated with recent science examples. Second presentation on DRSP. They thought we were farther ahead than many other big projects were, very impressed with this. Operations. What is the plan for reconfiguration. This will be driven in some sense by the DRSP. Conway--we don't really know what it will do so versatility should be a feature of the plan. Holdaway--demand may well evolve. Conway--cycle through on 9 month timescale. With 40 configurations and four antennas every three days then this limits time spent in the most compact configuration. There will be an iteration, with input from other IPTs via the Operations telecon, and from the DRSP, and the reconfiguration plan will evolve. Design Reference Science Plan--reviews received, closed since early September when submitted to the ASAC. A few areas were late, CSEs and SZ have now been added. Outflows also added. ASAC members reviewed the proposals, comments were received and authors were asked to respond or not. Future work also noted--correlator setups, etc. Calibration accuracy needed for the programs. Computing IPT would like a similar effort for the Early Science. Hills noted that the item on the agenda to discuss the memos from D'Addario had been missed out. Hills- loss of sensitivity which results from loss in specification on phase coherence is a critical issue. Holdaway--is in discussion with Larry. Larry says the atmosphere won't limit sensitivity 95% of the time. Losses due to phae fluctuations and decoherence set equal to electronics. I think that phase fluctuations in electronics should be compared to those in the atmosphere. Hills: Loss of coherence is straight loss of sensitivity--there all of the time. Second issue accuracy after a certain amount of integration. We need to look at this very closely. On coherence 2.5x slacking spec but actual accuracy one integration to the next is 5x worse. This is a pretty dramatic. Wootten said that as arguments converge there will be a joint telecon between Systems Engineering and the Science IPT to discuss this. Imaging--nothing substantial to report. SSR. Lucas noted news from correlator CDR had dominated the last agenda. A Data rate discussion also occurred. New correlator filter design will increase the data rate and we cannot increase it too much owing to expense on archive and other elements. Now we think we will take into account the DRSP information and understand the data rate for these programs as input for the prescription. Deadline of end of year for that. Do this during next face to face meeting in November. EvD: This is good to hear. RL: Top priority programs don't really always drive the peak data rate. We will make a plan on how to get the appropriate information together. For face-to-face meeting we will review the software, consequences of the calibration plan also. Discussion document on export data format also. Site: Order in which pads are built. The inner configuration will be built, owing to its complexity, after the ring of pads surrounding it. Both sets should be available for early science however.