Minutes of the FT Uppgrade Meeting held on 20/7/99 ================================================== Present ------- Tim Greenshaw, Derrick Hill, Gary Markey, John Morris, Dave Sankey, Terry Sloan, Graham Stokes. Action Items from Previous Upgrade Meeting ========================================== Gary ---- The last 0.5mm FR4 PCB delivered to DL has been inspected and HV tests done. The board looks good. Remaining minor problems have been discussed with SpemCo. The HV test results were OK. The trip to SpemCo on Thursday 15/7/99 was disappointing. The promised complete set of boards for one chamber was not ready for inspection, though by the end of the visit a set of 6 large panels (for the front and back walls of the chambers) was ready. Of these the three of one handedness were OK and have been transported to DL, the three of the opposite handedness were not. One of the poor boards had problems with a track and on all of them the slots were cut in the wrong place. The latter error arises from a mistake in the CAD files which has now been rectified. None of the side walls were ready. SpemCo now say they will deliver the remaining boards on 22/7/99. The importance of them keeping to this schedule has been stressed as Derek Morrow is to come to DL on the 22nd to help with the glueing of the first set of PCBs to the Nomex panels (using vacuum bag technology). All bar one of the Nomex panels are now at DL and look very good. The final panel is to be delivered in September. The complete surface table looks very nice. Gary will order Aluminium honeycomb for the remaining 2 tables. Action ------ Gary Keep on nagging SpemCo. Order Alu. honeycomb. Graham S -------- Graham showed us his design for the inner and outer supports of the new^2 chambers. He proposes to take about 5mm off the inner tank ring, to give plenty of space for installation, and add a thin aluminium inner support ring. He has designed an outer ring structure to support the chambers at the correct position, but pointed out that the machining of this would be quite difficult and possibly expensive. He proposes to produce a new design based on a set of short aluminium arcs. These could be matched to the castellations on the Nomex panels in some way. There as some worry about exactly where the bolt holes in the U chanels in the tank are located, but it was pointed out that matching holes can easily be machined in our support structure if it should turn out that the drawings we have are innaccurate. Graham will check the holes in the radial chamber at DL. This will give us some idea if the drawings correctly represent the real world! Graham has also designed an aluminium replacement pre-amp cover and put the construction out to tender. The thickness is as yet undefined. We would like the covers to be as thin as is feasible. The final design will probably have to await the HERA shutdown so we can look at the tank and check that the aluminium fits. (There may be problems with straight/rounded corners as the aluminium can not be folded to exactly the shape of the original moulded plastic pre-amp covers.) I think we need 284 (say 300) pre-amp covers. (Please check this!) Action ------ Graham Modify design of outer support structure. Look at Radial and try and find plastic pre-amp cover. Tim --- The remaining Noryl measurements (with pins inserted) have yet to be done. Don couldn't find limits for the wire tensions, but Tim will derive these from the tables of measured wire tensions for the old planars; these have been given to him by Graham S (``borrowed'' from Graham H's files, sorry!). The nominal tensions are: 500g for the 120 micron diam. Cu-Be field wires. 125g for the 40 micron diam. Au plated W wires. These correspond to stresses of about 430 x 10^6 Pa for the field wires and 980 x 10^6 Pa for the sense wires. To put this in context, Young's modulus for Cu is 130 x 10^9 Pa, for W is 410 x 10^9 Pa. Action ------ Tim Get Noryl measurements done. Extract wire tension limits. Action Items from Test Meeting ============================== Derrick has brought with him: CAEN pods. Additional feedthrough (we now have two). Analogue 'scope. FADC. Dave has all necessary software. Tim has brought 12 SHV to ``funny lemo'' cables from Don. He was not able to find a front panel extender card. (One was found, currently in the BDC crate in the Rucksack at H1, but this is needed for H1 operation by Guenter Eckerlin.) Don is looking for another card. Outstanding are now: CAEN mainframe. 4 SHV to lemo cables (in crate with CAEN mainframe?). Action ------ Don Chase up CAEN mainframe and front panel extender. Studies of Pins =============== Dave and Derrick have looked at the ``series 2'' pins under the microscope and observed: a) The ends appear pitted. b) The nickel is visible over a length of a few mm at the chamber end and some screw-thread like banding is also visible. c) A burr is visible at the end of one of the pins. (For picture see http://hep.ph.liv.ac.uk/~green/fthome.html, follow links in information for this meeting.) Furthermore, Gary reported that during construction of a cell, it was difficult to get wire through one of the pins and that the wire then broke when this pin was crimped, suggesting that there was some debris in the pin. Conversations with Butty at Medelec resulted in him thickening the gold plating, but the nickel is still visible at the chamber end, as is apparent in the pictures of the ``series 3'' pins he sent us. (See web site again.) The gold is apparently removed during the swaging process. The banding visible on the series 2 pins can no longer be seen. He has also agreed to insert wires into the pins and remove all burrs to prevent the above problems. Comparison with pins machined for the previous planar chambers suggests that the series 2/3 pins may well be OK; the pitting observable may actually result in fewer unpleasantly sharp spikes than are visible on the original pins. A test is necessary however. It was decided that Gary will construct a cell with the series 2 pins (of which we have a few hundred) and that this will be gassed up in a tube and HV tested by Derrick. We will also get Butty to send us enough series 3 pins for one complete chamber. Gary and his team can then construct a chamber with these. With a little luck, this will be a perfectly good chamber. Depending on the outcome of the tests of the cell, we can place the order for the remaining pins or get Butty to do some more development work. Action ------ Gary Construction of test cell. Derrick HV test of test cell. Studies of crimping =================== The above test cell will serve to study the crimping procedure. Tensions can be observed over the next month or so to check there is no slippage. Action ------ Gary Look for signs of slippage in test cell. Software ======== John went through the software task list (see web site) and promised to organise a software meeting at Lancaster, to which Eram Rizvi will be invited, within the next two weeks. Action ------ John Organise software meeting and make sure we start to make progress on, in particular, pattern cluster finding, segment finding and segment linking. Next meeting ============ Tuesday 7th September 1999. There will be plenty of opportunities to get involved in testing at DL in the meantime!