Minutes of the Meeting of the Technical Board ============================================= January 17th 2001, 9:30 - 12:15 Hera (J. Spengler): --------------------------- A short summary of the previous HERA coordination meeting was given. Both H1 and Zeus have problems with their new vertex detectors. Zeus announced a delay of about three weeks. In addition, some of the Hera activities are delayed as well. Right now, the impact on the overall schedule is not clear.The final end of the shutdown will be fixed in a special meeting of the spokes persons, HERA and directorate on Monday 12.02.2001. A delay of the shut-down could result in a delay of the tram operation. In this case, we can not profit much from this delay. Beam-pipe (J. Spengler): ------------------------ The status of the new beam-pipe is as follows: The reboring of the Al cylinders which is done by an external company is delayed quite a bit and will be finished by end of this week. In contrast to this, the mechanical milling of the pipes (Zeuthen workshop) goes very well. Up to now, three segments were damaged during the very delicate milling process and have to be redone. Nevertheless, 23 out of 31 pipes are finished and their quality ( = tolerances) is excellent. Additional press folding tests were performed and by middle of Feb. we expect all segments to be ready for welding. Target (K. Ehret): ------------------ The machining of the new target mechanics goes well and about 80% are done. Following the assembly vacuum and functionality tests will take place at Dortmund. Klaus proposed to use round wires with a diameter of 50 mu because the operational experience with such a wire was very good during the previous running period. He recommended the following wire arrangement: iI - W, iII - C, bI - Ti, bII - Al, oI - Ti, oII - C, aI and a II - Fe, Pd, Pt??. A question concerning Be wires came up. In view of the new Al-Be beam-pipes it seems to be worthwhile to discuss this issue with the machine people. Vertex (B. Schwingenheuer): --------------------------- A more robust solution was found to avoid the Helix 2.2 problems (falls asleep if not being read out for some cycles). The new Helix 3.2 has been submitted and the first chips are expected by Feb 6. Inner Tracker (Th. Hott): ------------------------- Thomas reported a small delay of the time schedule (MS12+) due to illness of one technician. The Maxx chips for the trigger driver board were delivered two months earlier. H. B. Dreis just arrived in order to finalize the ITR gas system. Outer Tracker (H. Kapitza): --------------------------- Herbert reported on the repair status of the OTR. All PC and TC chambers are disassembled. The HV boards of PC1+ - PC4+, TC1+- and PC1- have been repaired. Right now they are working on PC2+ and PC4+ in parallel. A detailed damage analysis of TC1+ followed. TC1+ has 10 HV shorts, 7 of which showed up in turn-on situations. 7 faults are in layer 1 and/or in the cap region. When reopening TC1+ last week, no obvious problems were found. 2 HV shorts disappeared when removing the cap. A possible explanation is that the gas box expands by a few millimeters when turning on the gas. This gives some additional space to layer 1 modules to acquire their "natural" shape which might result in electrostatical instabilities for some of the wires. Layer 2 and 3 modules will not change their position because they have been adjusted during assembly. In addition to these turn-on problems (TC1- has as well 7 shorts), in total 6 shorts have been observed occurring during the up-time of PC1+ and TC1+-. This number corresponds to one HV problem per 46 hrs, which is (as expected, because ~90% of the HV shorts are due to capacitor problems) about a factor 10 of improvement compared to the failure rate including the capacitor problem. Inner high-pt (M. Danilov): --------------------------- The new PT3- was tested and 7 wires had to be removed. PT3+ will arrive at Desy in 3 weeks. To reduce the installation problems the support for PT2 and PT3 has been made movable. PT1 is still under study. Tests with a Fe-source showed that the pulse height can vary between 55 and 75 a.u. depending on the atmospheric pressure. Software is being developed to adjust the HV accordingly. The work to reduce the noise level suffers from long term instabilities of the measured noise level. Mischa proposed once more to use the high-pt chambers as a tracking device. About 5 tracks per event (5 MHz) can be reconstructed just using the inner high-pt information. The new trigger proposal has been extended to Muon tracks and clear evidence for Muon candidates was found. In min. bias events no Muon tracks were observed. See pdf-file containing all the transparencies. (Note of the ignorant minute taker: is this a solid proof that this trigger works and has sufficient suppression?) Outer high-pt (A. Schwartz): ---------------------------- Alan presented a detailed task list. Using the test setup in hall 5 the ASD8 noise could be reduced by an order of magnitude. The oscillation problem can be reduced by separating the read-out cables. This helps quite a bit when only a few boards are connected. However, this solution is very difficult to realize for the complete chamber. RICH (P. Krizan): ----------------- Peter reported that some PM's will be replaced in spring. Up to now, nobody has been found who can handle the gas system in the future. TRD (V. Saveliev): ------------------ The test area in hall 1 has been prepared and they are waiting for the delivery of the hit boards. The production of the FE boards at Desy continues as planned. ECAL (S. Shuvalov, M. Bruschi): ------------------------------- Sergei reported on the upgrade status. There is no argument to replace the innermost modules. Therefore the replacement procedure will not be tested. A Co source is available to measure the longitudinal profile of the innermost modules. Some mechanics for this test is in preparation. The upgrade of the inner HV system is almost finished. Up to now, all inner bases and 40% of middle/outer have been modified to improve the noise situation. According to Marco, the first modified ADC board (gain has to be reduced to compensate for the larger signals due to the CW base modification) will be tested his week. 1000 channels will be modified per week. All boards will be available by mid March. Mechanical supports to improve the Sharc connection were proposed by Mr. Quehl. All 250 supports will be ready in a few weeks. The tests of the energy inhibit card at Bologna revealed some pick-up noise problems in the analog part of the board. In order to improve the slow control, high and low voltages will be monitored and scalers will be installed to measure the pretrigger rates. MUON (P. Karchin, U. Husemann): ------------------------------- Paul expressed his concerns about the current noise levels in West Hall. They are much higher than during the running period which makes it difficult to judge on the success of the improvement program. The reinstallation of both MU3+ and Mu4+ is somewhat behind schedule. A test setup with the pad electronics has been prepared at MPI-Heidelberg and they are looking into different options. Ulrich summarized the situation of the Muon pretrigger electronics. Most of the pretrigger link boards (PLB) are in Dortmund to improve the fixation of the optical links. The pixel mapping boards (PMB) are tested right now and the pretrigger coincidence units (PCU) need some small repairs. The complete system will be reinstalled by middle of May. First Level Trigger (H. Fleckenstein): -------------------------------------- All FLT setup information is now available in one data base, which can be accessed by DAQ. In order to speed up the message transfer, the RPF protocol is being modified. The channel masking of dead and hot wires (OTR) and latency effects have been included in the FLT simulation. For hard selected J/psi --> mu+mu- events the efficiency per track was found to be 23%. This number includes the pretrigger system eff., but not the pad efficiencies. The upgrade of the trigger link boards is underway. However, there will be a lack of manpower for the exchange of hardware. Second Level Trigger (P. Kreuzer): ---------------------------------- The ITR was integrated into the SLT code. When comparing the SLT algorithm before and after ITR ingration, a drop in efficiency is observed. This is due to misalignment of ITR chambers and due some software problems. L2Magnet code was upgraded. Si8, MC1 and MS01 hits were added. The ROIs need further optimization. The CnA software is updated. DAQif (interface between Arte DST and raw event format) has been updated (OTR and Muon); ITR will be included soon. A realistic simulation of the SLT requests has been made which will allow to optimize the switch performance by modifying the SLT switch connections. Fourth Level Trigger (J. Hernandez): ------------------------------------ As soon as the actual reprocessing is finished, the Linux system of the farm will be upgraded. For this purpose, a customized HERA-B installation was produced which has been included to the Desy installation server. The CAN bus control for power on/off, temperature and voltage monitoring is under preparation and will be installed in March. The data logging will be improved by using a dedicated powerful logging machine (up to now, an offline machine (hbserv) was used). As a second topic, Jose described the planned upgrade of our online computing. The present configuration has several disadvantages: too many online servers, different Linux installations, dependence on AFS. The number of server machines will be reduced, hb-con machines will be removed, all PCs will have the same Linux installation and the online running will be decoupled from AFS. Data Aquisition (V. Rybnikov): ------------------------------ The RPM implementation with threads discussed in the last meeting is finished. The new SHARC to PCI driver is ready. The work to improve the switch performance by changing the connection scheme has started and new cables for the SLT-switch connection were ordered. Mogens Dam came to Desy and tried to repair the bad SLT PCs. Some of the problems are still pending due to missing spare parts.