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CSV Plan status Robert Laing ESO Science IPT

CSV Plan status Robert Laing ESO Science IPT. Recent changes. Complete rewrite to take account of rebaselining and revised delivery schedule Proposal for delay to Early Science Relation to AIV and Operations

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CSV Plan status Robert Laing ESO Science IPT

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  1. CSV Plan statusRobert LaingESOScience IPT

  2. Recent changes • Complete rewrite to take account of rebaselining and revised delivery schedule • Proposal for delay to Early Science • Relation to AIV and Operations • Change of scope: additional ALMA-J antennas and receiver bands; initial consideration of 7m array • Schedule • Staffing plan • Verification matrix

  3. Definitions • ASAC report Oct 2005. No conceptual changes, but terminology is different from that of Jan 2005 AIVC meeting and earlier ASAC meetings. • Assembly, Integration and Verification (AIV) is a construction activity led by the JAO Project Engineer to integrate the ALMA sub-systems into a single working system. • Commissioning covers initial testing, interaction with SI and other construction IPTs to identify and resolve faults, optimization, training of Operations staff and documentation • Science Verification (SV) is the end-to-end testing of an ALMA science mode done using a science project proposed by an external user (ASAC). • An ALMA public image (API) is a large-scale project whose primary purpose is to convince the wider community/public of the value of ALMA (ASAC). • CSV = Commissioning and Science Verification

  4. Equipment available • CSV starts with the delivery of a verified 3-element interferometer at the AOS, although there are pre-commissioning activities in support of AIV. • Bands 3, 4, 6, 7, 8, 9 available (maybe not 4 and 8 on the first few antennas) • All types of 12m antenna used for inteferometric commissioning. • Test single-dish and interferometric observing in parallel; 2 subarrays. • Initial configurations compact; thereafter First Science Configurations as already defined • Baseline correlator + Tunable Filter Bank

  5. Early Science • Current schedule and definition of Early Science assumes an antenna delivery profile which is no longer valid. • Decision on what modes to offer for early Science would have to be made very soon (~3 months) after the start of CSV. • Therefore (in accordance with ASAC recommendations) consider a delay to Early Science, but enhanced capability. • Current proposal is a straw man, for discussion, but is consistent with the most recent Operations budget and staffing plan.

  6. Early Science – proposed definition • At least 16 antennas fully commissioned (more in process of integration) • Receiver bands 3, 4, 6, 7, 8, 9 • Interferometry in single field or pointed mosaic mode • Significant (TBD) range of spectral modes, including TFB • Circular and linear polarization (not mosaic) • Single-dish mosaic (position and beam-switch) and OTF. • 2 subarrays operational

  7. Timescales • CSV milestone on handover of verified 3-element interferometer at AOS (currently 2008Q4) • Early Science decision point (which modes to be offered) CSV + 12 months • Early Science CSV + 20 months • (For reference, 16 antennas available for commissioning CSV + 15 months)

  8. AIV Activities • AIV is responsible for: • Antenna acceptance • Antenna integration • Single-antenna tests at OSF • Single-baseline interferometry at OSF • Single-antenna and single-baseline interferometry at AOS • CSV team needs to be closely involved in these tests, both to contribute experience and to train new staff. Details are TBD.

  9. Main CSV activities (1) • Close-packed array • antennas 1-4 on closely-spaced pads • Band 3 only • Early Science array • Additional bands • Baselines to 4(?)km – depends on pad availability • Correlator configurations • Mosaics • Polarization • Addition of total power data • Verification against Science Requirements

  10. Main CSV activities (2) • Observation calibrations • Phase calibration, fast switching and WVR development • Calibrator surveys • Temperature and flux scale • Bandpass • Instrumental polarization • Antenna and array calibrations • Pointing, focus • Primary beam and surface • Antenna location • Delay

  11. Main CSV activities (3) • Single-dish modes • Mosaic with beam and position switching • On-the-fly mapping • Autocorrelation and continuum total power • [Frequency switching] • Total power calibration • ACA 7m array (from CSV + 12 months, roughly)

  12. Task durations (1) • Split into broad categories: • Commission observing modes • Observation calibration • Array and antenna calibration • Single-dish • ACA 7m array • Estimate durations and approximate phasing within CSV phase up to early Science • Many activities in parallel (flexibility; weather) • Assumptions about SV fraction, array downtime

  13. Task durations (2) • Current numbers: • Modes 230 days • Observation calibration 150 days • Array/antenna calibration 95 days • Single dish 60 days (in parallel) • ACA 7m array TBD (in parallel) • Assume 20% downtime on average (more initially) and 10% SV fraction • Consistent with a ~20-month programme

  14. Staffing • Project Scientist + 2 commissioning scientists • Science IPT staff on rotation • Division of Science Operations • Ad hoc specialists • ARC staff on rotation Concept is that Operations staff form an integral part of the commissioning team: there is no “handover”

  15. Staffing profile Required/available 2008 20/31.5 2009 27/33 2010 34/35.5 Numbers 2011-2012 TBD, but essentially no Science IPT manpower available to supplement Operations. Marginal, given the additional duties of Operations staff: more tuning required.

  16. Science Verification • Discussed by ASAC in October 2005 • Main goals • Test ALMA modes end-to-end using projects from user community • Feedback to CSV team • Early access to ALMA data for the community • Modes fully commissioned before SV; PS responsible for decision to issue call • Open call for proposals, not using formal machinery; review for scientific value (external) and feasibility (CSV team) • Data public immediately • Projects executed by CSV team/Operations; include QA • ALMA Public Images are a subset of SV

  17. Verification • Draft verification matrix available • Need to demonstrate that ALMA meets its science requirements, but with an incomplete array. • Verification matrix is more complex, parameterized by number of antennas, range of baselines, ….. • Scaling for sensitivity is straightforward, image fidelity and dynamic range somewhat less so.

  18. Commissioning after Early Science • Much still to do, including completion of ACA 7m array, Band 10 • Primarily carried out by Operations staff • Planning just starting …

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