Proposal for November 1996 Hall B Commissioning V. Burkert, D. Sober, and CalCom Working Group 16 July 1996 INTRODUCTION As can be seen from the proposed accelerator schedule, only 6 days of beam are planned for Hall B in November, with a 10 week gap before the next beam is due in the Hall. Then, beginning on February 5, beam will be delivered to Hall B continuously, with only six 2-day breaks scheduled during the next 15.5 weeks (up to the May 24 Memorial Day holiday, which is as far as the 1997 schedule has been announced.) The November run is primarily for accelerator beam tuning, presumably first at 800 MeV and then at higher energy. Only if a satisfactory beam is obtained in less than 6 days will there be beam time available for beginning the CLAS commissioning, and the quality of the beam during that time may not be exactly what we would wish. Nonetheless it would be extremely valuable to begin checking out the Hall B detector systems in November, so that major problems identified under beam conditions can be fixed during the 10 week shutdown which precedes the long commissioning run. ----------------------------------------------------------------- | Accelerator Schedule (as of 10 April 1996): | | | | 11/14/96-11/21/96 Beam to Hall C E-94-014 (Stoler) and | | for commissioning Hall A | | | | 11/22/96-11/27/96 First beam to Hall B | | | | 11/28/96-12/01/96 Thanksgiving Holiday | | | | . . . | | | | 02/05/07-02/17/97 4 GeV 30 uA CW polarized beam to Hall A | | E-89-003/-033; | | 100 nA to Hall B; install T20 in Hall C | ----------------------------------------------------------------- The goals of the July 16 meeting were 1. To set achievable goals for system readiness for the November run, including the cosmic-ray calibration period which precedes it. 2. To set relative priorities for measurements to be made during the November run, with the understanding that the time actually available for such measurements may be considerably less than 6 days (and possibly 0), and that some or all of the program may have to be postponed to February. PROPOSED SCHEDULE: 1. Installation of detectors should be temporarily suspended 6 weeks before November run, i.e. 10/11/96. 2. Week of 10/14: Move south clam shell and forward carriage into installed position. Complete cabling of detectors. 3. Weeks of 10/21, 10/28, 11/4: Cosmic-ray testing of all installed systems (using trigger counter at CLAS target position) 11/01/96-11/21/96. 4. Weeks of 11/11 and 11/18 (through 11/21): Complete installation of beamline, target, mini-torus, add scintillator in place of region I, etc. 5. Ready for beam (as available) 11/22/96-11/27/96. Adequate personnel must be made available for both the cosmic-ray and the beam runs. MINIMAL READINESS REQUIREMENTS FOR COSMIC-RAY AND BEAM TESTS: o Minimal DAQ and trigger (Level 1), run control o At least one sector installed, instrumented, operational: Reg.II + Reg.III + TOF + EC + CC Choice of sector coordinated with LAEC and LATOF: 3 or 5 o'clock (Reg.I availability would greatly enhance value of tests, but not expected) o Additional chamber of scintillator outside mini-torus (in lieu of Reg.I) o Basic beam line instrumentation: BPMs (Accel. Div.) vacuum Faraday cup targets for (e,e'): 12C (0.3, 3, 30 mg/cm2), CH2 (3 mg/cm2) mini-torus o CLAS torus o Tagger magnet GOALS OF COSMIC-RAY RUNS o Check out trigger, DAQ, and run control o Check on-line monitoring and event display o Check operation of installed detectors (HV, timing, ...) o Check reconstruction software o Perform minimum ionizing particle calibration of ECs, TOFs (?) o Other: To be provided by Working Groups o Take data with torus B field OFF/ON (leave ON for beam run) ORDER OF MEASUREMENTS TO BE MADE WITH BEAM Estimated Priority 8-hour shifts* o Begin with CLAS torus field on o Tune beam line up to tagger magnet 3 (accel.) Tagger magnet on (e beam to tagger dump, to protect CLAS); no radiator o Measure background rates (from tagger dump) 1 A in CLAS and tagger detectors o Tagger magnet off o Steer e beam to Faraday cup 1 (accel.) o CLAS torus on, no target: o Optimize backgrounds from beam 2 A o Tune lowest posible current 0.5 (accel.) A o Thin C target in (L < 10^33 cm^-2 s^-1 => 3 mg/cm2 12C at 100 nA) o Electron triggers (Level 1): TOF.EC.[CC], ...LAEC... o Vary EC energy threshold to get clean trigger 0.5 A o Check events using CLAS Event Display 0.5 A o Take data with EC.TOF to check CC efficiency 0.5 A o On-line histograms for diagnostics: to be defined by Working Groups o Write data for off-line analysis 4 A o Test Level 2 trigger in 1 sector (?) 1 B o Mini-torus on o Optimize mini-torus current, observing drift chamber currents and TOF, EC, CC, Reg.I scint scaler rates 1 B o Take data with minimum ionizing trigger in EC, TOF for calibration 1 B? o Tagger magnet on, radiator in, beam counter at Faraday cup: o Write data to check tagger counter timing, etc. 2 A __________ Total 18 (= 6 days) * The time estimates include the overhead in turning on magnets, etc.. They are based on optimistic estimates for the requirements of the accelerator group. In the event that beam tuneup and steering takes longer, we have the option of o scaling back the time allotted to commissioning tasks, or o dropping tasks of lower priority from the list.