CALICE MAPS Meeting, RAL, 20/05/08 ================================== Present: Jamie Crooks, Paul Dauncey, Anne-Marie Magnan, Owen Miller, Marcel Stanitzki, Renato Turchetta, Mike Tyndel, Nigel Watson Minutes: Paul Minutes of previous meeting: No changes. Renato has confirmed that Mark Prydderch is able to act as external referee for the FDR. Report on PDR: Jamie summarised the outcome of the PDR which was held on Thu 1 May. We will produce a sensor V1.1 which will be consistent with the existing PCB and DAQ. All pixels will be shapers but the two capacitor variants will be retained. The test structures will also be converted to be shapers. The three known bugs will be fixed and Rebecca Coath will join the effort to attempt to implement two extra trim bits (to go from four to six bits total). Since the PDR, Jamie has scheduled some days within the contingency to do the updates to the test structure resulting from Rebecca's work. These would be following the FDR on Fri 13 Jun. If there are a lot of changes following the FDR, then we could have an update to the FDR just before submission. Renato reported that we do not yet have a firm price for the next fabrication round; our budget is 35k total. The splits we want are, in priority ordering: 6 wafers, 12mu epi, deep p-well 3 wafers, 12mu epi, non-deep p-well 3 wafers, 12mu epi, deep p-well, high-resistivity epi 3 wafers, 5mu epi, deep p-well We need both to get high-resistivity wafers and get the foundry to use them. The former seems straightforward. The latter is more tricky; the foundry requires deep p-well under all circuitry except the sense diodes. This would require us to cover the memory columns and put a deep p-well guard ring around the outside of the bulk pixel array. Any change to the design at this stage needs to be regarded as having some risk so whether these changes are worth doing for the high-resistivity option (which is not essential for our programme) needs some thought. Renato and Jamie should think through the issues and present this at the next meeting, together with the motivations for studying the high-resistivity option in the first place. Sensor 1.0 testing: Jamie has replaced several wafer #10 sensors with wafer #8 ones and has seen a much higher yield; see his spreadsheet on the usual web page. This means the issue seems to be related to the wafer, not changes to the gluing or bonding process. Owen showed results on his trim studies; see slides on the usual web page. He finds the trim unit is around 3TU with a modified PCB. There was some discussion on the cause of the double-band structure on slide 7 but it is not yet understood. The missing trim bits in slide 25 were thought to be due to the step size in the threshold scan so Owen will try interpolating between the points to get a more accurate value. [Note added after meeting: Marcel had contributed some plots for this study and these were distributed after the meeting; see usual web page.] Anne-Marie showed some first results using a laser system at Imperial on charge sharing; see usual web page. So far, no diodes are visible in these scans, which does not match well to the simulation. Paul also showed results from the laser system on pixel uniformity and a comparision of quadrant 0 and 1 shapers. The apparent crosstalk seen when unmasking pixels could be serious and needs further investigation. Nigel reported that they have not got the cosmics system running due to missing information on the trigger distribution (and potentially other issues). Paul will get Matt Noy to send Nigel the required connector locations. Conferences: Marcel has submitted several abstracts for conferences; see slides on usual web page. We need to see how many are accepted. For TWEPP and IEEE, the talks will be more technical so the RAL/TD people would be the more natural candidates. The most urgent is ECFA in Warsaw, starting on Mon 9 Jun. We have asked for a MAPS talk in the ECAL session but this has not yet been confirmed. Assuming it is, then the candidates available were John Wilson and Owen. Nigel will fix this up with one of them. Marcel will be giving the SiD ECAL talk at this meeting and so can mention MAPS in this as well. Next meeting: The next meeting will be by phone on Wed 4 Jun at 13.00. This will be followed by the FDR on Fri 13 Jun at 10.00.