1. Itzhak Tserruya, July 7, 20041  Towards HBD Proposal  Ongoing activities and plans for the next two months Itzhak Tserruya HBD meeting at BNL, September 15, 2004

2. Itzhak Tserruya, July 7, 20042 HBD Proposal: (I) Layout 1. Physics motivation and background (Axel) - importance and significance of low-mass dileptons - summary of results at lower energies - expectations at RHIC - combinatorial background in PHENIX baseline detector and role of HBD 2. Ideal Monte Carlo simulations, system specifications (Summary of TN391) (Zeev) 3. Detector concept (Itzhak) 4. R&D results (Itzhak and Zeev ) - GEM gain in pure CF4 - Hadron blindness: * Photo-electron efficiency: - Gain saturation * Pion rejection factor: KEK results - Discharge probability - CsI quantum efficiency - Ion backflow - UV transparency of CF4 - Operation wih CsI photocathode - Absorption in H2O and O2 (Babak) - Tests in PHENIX environment (Craig) - Aging studies 5. Monte Carlo simulations and system performance (Ilia) 6. Electronics (Craig) - analog (Craig) - digital (Chi) 7. Trigger (David, Matthias) 8. Detector design and construction procedure (Itzhak) 9. Gas system (Craig) 10. Detector assembly and test facility (Sasha) 11. Estimated cost, Responsibilities and Time Table (Craig, Itzhak)

3. Itzhak Tserruya, July 7, 20043 HBD Proposal: (II) Logistics 1. Write all text in latex 2. Web page: https://www.phenix.bnl.gov/WWW/p/draft/fraenkel 3. Timetable u All material in place by 1 st week of October. u Release to the Collaboration in October Core Week?

4. Itzhak Tserruya, July 7, 20044 Ongoing Activities 1. Large GEM test 2. Full size prototype 3. Monte Carlo (see Ilia’s presentation)

5. Itzhak Tserruya, July 7, 20045 Large GEM Test  12 Large GEMs in house 8 standard + 4 Au plated active area 228 x 237 mm 2 high voltage segmentation on top and bottom faces  15 Frames with spacer in house  PCB with hexagonal pads ready  Stretching and gluing devices ready  Stainless steel box ready and vacuum tested  Extension to CsI evaporator under construction

6. Itzhak Tserruya, July 7, 20046 GEM design- Bottom side (not to scale) Operational area (holes), 228mm Copper coated area, 232mm Bottom segment, 5mm Exact segmentation scheme for the bottom side: 1 segment of 7.5mm +45 segments of 5mm + 1 segment of 4.5mm Bottom segments are Staggered by 2.5mm with respect to the top segments 3mm 19mm 4mm for SMD resistors 3mm 241mm Kapton > ~400 mm Holes: 140 um pitch 80/60 um diameter Gaps between segments: As for COMPASS 237mm 241mm 12 Large GEMs in house: 8 standard + 4 Au plated active area 228 x 237 mm 2 HV segmentation on both faces

7. Itzhak Tserruya, July 7, 20047 GEM design - Top side (not to scale) Gaps between segments: As for COMPASS Operational area (holes), 228mm Copper coated area, 232mm 3mm 19mm 4mm for SMD resistors 3mm 241mm Kapton > ~400 mm Holes: 140 um pitch 80/60 um diameter 237mm 241mm Top segment, 5mm Exact segmentation scheme for the top side: 46 segments of 5mm + 1 segment of 7mm

8. Itzhak Tserruya, July 7, 20048 G10 Frame Material G10 Thickness 1.5mm Width 5mm 249mm 5mm Thickness 0.3 mm 240mm + + + + 2.5 4 holes D2.5mm Very fragile but needed to limit the dead area Estimated dead area for a 5mm wide frame is 6%.

9. Itzhak Tserruya, July 7, 20049 The electrostatic pressure between GEMs: 0.5 N/m 2 Limit the sagitta to 100μ  Need a tension of app. 40 N/m Stretching Device

10. Itzhak Tserruya, July 7, 200410 Gluing Device Glue dispenser: 100μ thick layer 4mm width

11. Itzhak Tserruya, July 7, 200411 Full-size prototype 1. Box design finished 2. Working on the design of tooling and jigs 3. All raw materials ordered and most of them already in house. 4. The plan is to construct a full size box and to equip it with one detector element only. 5. Once tested, the box will be shipped to BNL. Expected to happen by the end of the year.

12. Itzhak Tserruya, July 7, 200412 Plans for the next 2-3 months 1. Large GEM test : Sept-Oct 2. Full size prototype: Oct-Nov 3. Monte Carlo: Sept –Oct. 4. Conferences u CAARI, October 10.15, Texas Bob u IEEE, October 16-22, Rome, Craig