CALICE MAPS Meeting, RAL, 26/01/10 ================================== Present: Jamie Crooks, Paul Dauncey, Owen Miller, Tony Price, Marcel Stanitzki, Mike Tyndel, Nigel Watson Minutes: Paul Papers: It seems unlikely that the DECAL concept, at least in terms of the TPAC sensor, will continue beyond the existing sensors; no further design changes are planned or funded. Hence, we should push through the write-up of what has been done with TPAC and produce papers during 2010. Paul went through his ideas for how the results we have, or expect to have, should be divided up between the papers; see slides on usual web page. In terms of the numbering for the papers used there: 1 The DECAL simulations will be redone by Nigel. He will contact Anne-Marie to get the latest versions of her digitisation code. Marcel will be paper editor. This will be submitted to NIM. 2 This paper needs some further measurements using the laser and the Fe55 source (see below). Mike suggested removing the bulk results due to the overlap with paper 3 but there will be several more variants and possibly no bulk laser measurements in paper 3, so they will probably not be very similar. Jamie suggested saving the diffusion timing measurements for paper 3 as the significant result would be from timing differences for standard and hi-res sensors. Paul will be the paper 2 editor. The original suggestion was that this paper would be submitted to IEEE/TNS but this journal has a guidance paper limit of 8 pages while the current draft is 28 pages. Hence, it should probably be submitted to JINST. 3 There are quite a few measurements still needed for this paper but paper 2 should take priority. This paper will not include any radiation hardness results as these would take too long to do and it is not clear how this would be measured without a significant beam test programme. There could also be a problem with activation of the gold in the sensor PCBs at high fluences. 4/5 These will be started following the DESY beam test in March. Paul will check the impact factors for the various journals and check if Renato has views on which journal to submit to. The latex and plots for the two existing papers should be copied into the SPIDER svn repository and this will be done by Marcel or Nigel. The files for the future papers should be kept there also. Jamie showed some slides of the different variants of sensor available from the three TPAC fabrication rounds; see the last three of his slides on the usual web page. The first measurements to do are with Fe55 on the test pixels for 5mu deep p-well for pre-shape 1.0 on TPAC1.1. Fe55 results for the two deep p-well variants of the pre-sampler 1.0 test pixel on TPAC1.0 are also needed. These should be relatively quick to do but a longer run would be required to do the 5mu deep p-well pre-shaper 1.0 bulk pixels ("array") on TPAC1.0, which Marcel estimated would take ~4 weeks. Conferences: Marcel raised the issue of conference abstracts. We have results to show, e.g. the CERN beam test data, but we may be limited by travel funds. Marcel will circulate a list of upcoming conferences to see who would be available and able to go. DESY beam test: Jamie also showed some slides on sensor preparations for the DESY beam test; see the first part of his talk on the usual web page. We should have two sensors for each of the three non-standard TPAC1.2 sensor variants. There is an issue with there being very few unpotted TPAC1.2 sensors left of any variants. There is no problem with using the laser on these but the Fe55 photons will not penetrate the potting compound. Hence, it would be useful to collect every PCB and return it to RAL so that more TPAC1.2 sensors can be mounted if needed. There is a sensor PCB still at Bristol which should be returned asap. Paul will check for TPAC1.0 or 1.1 sensor PCBs at Imperial; there are no TPAC1.2 boards there. Birmingham has no PCBs of any type. An alternative to potting would be to use a transparent rigid cover over the sensors; CERN have used watchglasses to protect sensors. This seems reasonable but we would need to get these and check they work very soon if we are to avoid potting the remaining five sensors currently being bonded and trimmed. Marcel will chase this up. Jamie cannot start any new measurements until the CHERWELL1 design is completed (~April) which is also after the DESY beam test and hence when the USB_DAQs will become available again. Paul went through some details of the beam test EUDET interface and other issues; see slides on the usual web page. Paul will contact Erika Garutti to see if there are larger scintillators with HV and readout logic already available in the beam line at DESY. If not, then Nigel will ask John Wilson if he can get something suitable. Easter will limit the end of the beam test period; it is not known if the beam will run or not over the Easter weekend, but we should assume we need to finish before Good Friday (Apr 2). Starting on Mon 8 Mar would then give 3.5 weeks and this seems reasonable. If DESY do not want to grant us this much beam time, then starting on Mon 15 Mar is the best option as this will give more preparation time. Paul will contact Jaap so he can book this asap. When the dates are fixed, we should book transport and rooms. Paul favoured driving out with a car-sized van as this prevents delays and loss of equipment which are possible when shipping. Beam test analysis: Owen showed some slides on the MIP efficiencies; see usual web page. He uses a one-sigma square window, where the one-sigma is usually around 20mu, so the window is a square of roughly 40x40mu2. Extending this by the additional 25mu on each side as described in the talk therefore increases it to around 90x90mu2, which is effectively a little more than two-sigma. It was not clear how much of the efficiency increase is due to simply including more of the Gaussian tails; the stability of the efficiency to varying the window size should be checked. Tony showed some slides on the double-hit statistics; see usual web page. He finds some odd results for the calculated monostable widths which are not yet understood. Tony also looked at overall hit rates in electron runs with tungsten compared to pion and non-tungsten runs. It would be expected that the hit rate would be higher with tungsten due to the showers but this might be washed out by the noise rate. There were only a few showers per bunch train compared with the 8000 bunch crossings in the train. Next meeting: This will be at RAL on Wed 10 Feb, starting at 10am.