From dz@budoe.bu.eduThu Jul 18 08:52:12 1996 Date: Thu, 20 Jun 1996 12:35:27 -0400 (EDT) From: Dave Zimmerman To: zimm@Bnl.gov Subject: Minutes of Schedule Meeting (fwd) ---------- Forwarded message ---------- Date: Tue, 23 Jan 1996 09:00:31 -0500 (EST) From: MORSE@bnlarm.bnl.gov To: earle@buphy.bu.edu, monich@buphyc.bu.edu, varner@buphyc.bu.edu, OUYANG@buphyc.bu.edu, CAREY@buphyc.bu.edu, krienen@BNLDAG.AGS.BNL.GOV, messier@buphy.bu.edu, miller@buphyc.bu.edu, roberts@buphyc.bu.edu, worstell@buphyc.bu.edu Cc: c.disco@wmw.utwente.nl, koniczny@princeton.edu, lowenstein@BNLDAG.AGS.BNL.GOV, tkirk@bnl.gov, yamin@BNLDAG.AGS.BNL.GOV, roser@BNLDAG.AGS.BNL.GOV, lessard@BNLDAG.AGS.BNL.GOV, barton1@bnl.gov, geller@bnlux1.bnl.gov Subject: Minutes of Schedule Meeting Minutes of January 22, 1996 E821 Schedule Meeting We haven't had a schedule meeting in a while due to blizzards, etc. Encouraging progress has been made on the storage ring magnet testing. The time stability of the magnet is excellent. The short term time stability is better than 0.1ppm. This was our specification. The power supply had previously been tested with a resistive load. However, only NMR has this sensitivity. The long term stability is also excellent. After powering with cycling shown in g-2 note 223, for example, the field is ready to be measured within half an hour. This is a great improvement over the CERN magnet, which took many days to settle. Of course, the CERN magnet was not superconducting. The cryo/ magnet/ power supply/ quench protection is a major system. We have discovered many system problems which have been rectified: 1. We had false quench monitor triggers. Solution: We added filtering so we wouldn't pick-up the walkie-talkie. 2. The building drain froze flooding the building during the January thaw. Solution: We moved the cold Nitrogen exhaust line away from the building drain. 3. The cryo vacuum gate valves sometimes cycled spoiling the vacuum. Solution: We added code to the vacuum control system to prevent this. 4. There was a bug in the cryo control system which prevented updating of pressure readings. We found the bug and fixed it. 5. The compressed air system which controlled the vacuum and cryo valves sometimes exceeding the pressure specs. We added a pressure regulator and a drying system. 6. The UPS system failed. It has been fixed. One surprise was the asymmetrical forces on the wedges and pole pieces at low fields. We now understand that as due to the fact that they were designed to give a dipole field at 5200A. At full-field the mu of the iron is about 300. At half-field it is around 8000. In fact we see a large quadrupole moment in the field distribution at half-field. This is because the wedge angle is too large by 8000/300 at half- field! However, in order to get to full-field, we must ramp through the lower fields. The wedges were not adequately constrained against movement, ie. they moved at low field. This is being rectified. We have extracted the energy at 1000A, 1500A, and 2450A (half-field). The quench analysis agrees with the energy extraction data. We are writing a g-2 note. We have measured the "umbrella" effect in the magnetic field distribution after we extract the energy. However, it is much smaller than the CERN effect. Of course, the CERN magnet was not superconducting. John Jackson is calculating the forces on the wedges and pole pieces at low fields. Once we are sure we understand the effect, we will go to full-field. Although encouraging progress has been made, the "power magnet and shim" schedule has slipped about one month due to these unanticipated problems. Lee Roberts reviewed the progress at B.U. (see Fig.1). The electrostatic quadrupole electrodes should be here by Wednesday. Originally, they were scheduled to be here before Christmas. Yannis said this has caused a one month slip in the electrostatic quadrupole schedule. Wuzheng reviewed the inflector magnet progress. Last year the 0.5m prototype was successfully tested at KEK and at BNL in an external 1.5T magnetic field. The 1.7m inflector magnet was being tested at KEK during early January. The half-field test was very successful for the magnet and the superconducting shield. However, on excitation to full-field (2850A), it quenched at 1750A. We do not understand why it quenched. It was warmed up and examined. The quench occurred at the joint between the inner and outer coils. There was extensive damage to the joint superconductor. There is a slight possibility this magnet can be repaired. If so, the inflector schedule will slip by about one month. If we have to build a new one, it won't be done until next fall. Obviously, the project schedule now depends on the vacuum chamber the inflector branch points. I show below the project schedule if we don't install the inflector and electrostatic quadrupole for this year's run. I asked Hugh Brown to evaluate whether we can do the penultimate flash test this year with pion and muon injection without the inflector magnet. He is studying this. He mentioned that if we run the storage ring magnet at reduced field, this might give a good simulation of the flash without the inflector magnet. Respectfully submitted - Bill Morse. 96 Jan Feb Mar Apr May Task Name 2 16 29 12 4 18 8 29 20 V-line Construction XXXXXXXXXXXXXXXXX. . . . Cryo Prep .| . . . . . . . Cool-down .| . . . . . . . Power Magnet & Shim XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX Quad1 Test in Ring .| . . XXXX . . . Inflector BP .| . M . . . . . Vacuum Chamber BP .| . . M. . . . . AGS FY96 Run .| . . XXXXXXXXXXXXXXXXXXXXXXX Testbeam .| . . XXXXXXXXXXXXXXXXXXXXX- Tune Beam .| . . . .XXXXX . . Pi/Mu Injection Into Ri .| . . . . .XXXX---------