Minutes of Quickal meet 24 Oct. 1997 Present D.Imrie A.L.Lintern P.S.Flower B.Kennedy D.Cockerill D.Imrie Derek reported on recent measurements of APD's. These were DC coupled with the anode at ground He measured the gain of the Russian tube RIE 018 and reported a best gain of 13.8. He has also measured the gain of some of the Electron Tubes APD, The tubes that have been delivered are 7 off with a Ni grid at 400 lines /inch (16.4 L/mm) S Nos. 10001 to 10007 7 off with a Cu grid at 400 lines /inch (16.4 L/mm) 7 off with a Ni grid at 200 lines /inch (8.2 L/mm) S. No 10001 10002 10003 10004 Gain 9.9 12.2 11.8 12.9 QE 16.6 14.9 20.2 14.5 Gain (M) 8 7.1 7.2 7.3 The gain was measured using Eddy's rig. The QE is the manufacturer's figure and is determined by using a well established technique. The tubes have a standard bi-alkali caesiated antimony photocathode Gain (M) is the manufacturers figure. The voltage is not given and this figure should be regarded as tentative. Derek has also set up a rig with M. Osborne at Brunel and measured an APD S. No 10007 Gain 7.5 QE 18.6 Gain (M) 6.1 A correspondence check still has to be made between the two rigs A.L.Lintern Laurie is working on the beam hodoscope. He can only glue lines of fibres in at a maximum of 2 rows per day and has 6 rows left to glue. He has discussed the position wrt the test magnet at Bristol and it was agreed that this should remain at Bristol Work has now started on the magnet in the PPD beam line area and is expected to take about 2 weeks Laurie will start flushing out the magnet in the next week. He will also be taking some leave. P.S.Flower Paul reported that he has collected his glass samples from Peter Hobson at Brunel and had discussions on problems with HfF4 quality. Peter had shown Paul a mass spectrometer analysis of a sample of Russian HfF4 which had 40 ppm Fe contamination. It was felt that either a sample of the same material should be analysed at Sheffield, or Sheffield should be given blind, a sample containing a known quantity of Fe. Paul reported that there were problems with the availability of the glass melting rig at Sheffield and it was felt that Paul should concentrate on the analysise of the data gathered with JM HfF4 and present it to Peter so that he could approach JM with a view to asking them to undertake some more sample analysis. Paul reported that present indications were that the new Russian HfF4 gave poor transmission when made into bigger samples. This may be caused by insufficiently reduced Fe, but to insure the effect is not optical a small sample would be cut from a big block and measured He will be on leave Tuesday and Wednesday. B.Kennedy Bruce was congratulated on the birth of a child. Bruce has been working on the OST document He has also worked with J.Hays on modifications to the end cap simulation code to take account of the cut away regions at the edges, this is now working. Bruce is working with Len Denton to investigate discrepancies between their calculated dimensions for block positions D.Cockerill Dave presented data from Gavin Davis and Dave Barney which suggested a linear relationship between energy resolution and crystal length. This looked anomalous and needs checking as it implies we are not at a well chosen crystal length. He also reported that recent calculations of neutron flux by Miko Hutanin taking into account the 5mm Al support plate suggested a significantly reduced radiation loading for the electronics. Dave then gave a listing of important dates 27-31 Oct. PDR readings, ECAL week 4 Nov. LHCC ECAL referees meeting 4-5 Nov. CMS Internal ECAL referees meeting 7 Nov. Reaction of LHCC referees 10 Nov. Cover & colour pages go to print 1 DEC FINAL DRAFT DATE !!!!!!!!!!! 8 Dec. 250 copies printed 15 Dec. 100 copies to LHCC secretariat 20 Jan 1998 CMS ECAL Open presentation to LHCC Next week ECAL Then on the test beam with the 3 by 3 array Dave at CERN till Nov. 9 Hope to test the Lyon amplifiers on the VPT's