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16 DC’s on the support !!. 4 Levels of test Pretest HV Air + tightness Aquarium : functionality + tightness Cosmics Lab : other preamps + correct signal assignment inside COBRA up to panel == preamp calibration Cosmics p E5, with and without COBRA == preamp calibration + alignment.
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16 DC’s on the support !! DC status, 18.07.2007, je
4 Levels of test • Pretest HV Air + tightness • Aquarium : functionality + tightness • Cosmics Lab : other preamps + correct signal assignment inside COBRA up to panel== preamp calibration • Cosmics pE5, with and without COBRA== preamp calibration + alignment 17 DC‘s through level 2 + 13 DC‘s through level 3 + 3 DC’s partially level 3 DC status, 18.07.2007, je
Tightness a) Clean old pair with He b) New DC pair in c) Flush with 50%-50% 49.5% • HV in pure He (Aquarium closed) • As above • Flush He in Aquarium • Open Aquarium 48.6 % ~1 % DC status, 18.07.2007, je
a a • Sr90 , slits of > 5 cm • All signals present (anode asymmetry only if up and down) • Circle only with 4 correct cathodes • separation of 2 periods a Assy anodes Assy cath down Assy cath up DC status, 18.07.2007, je
Calibration AsyAn0 = [{(l/2+x)r + R} - {(l/2-x)r + R}] / [{(l/2+x)r + R} +{(l/2-x)r + R}] = 2x / ( l + R/r) AsyCat/(sum anode) = a+bsin(2*pix/period + phase) DC geometry Ok to +-.05 mm Iteratively : a) Project with a and optimize ratio of anode preamp gain or thin slit in the middle b) Fit cathn /(sum Anode) Clever fit like Boris and Sacha DC status, 18.07.2007, je
DC test with Cosmic ray (in Lab.) DC status, 18.07.2007, je
cosmic ray counters for DC wire alignment • 10 counters (10 plastic scintillators + 20 PMTs) are prepared • DC wire alignment will be performed w/o COBRA field DC status, 18.07.2007, je
cosmic ray counter for DC wire alignment (2) • event rate is estimated by MC # of hit / 5 hours • beyond hit rate map is corresponding to 5 hours running • “1 counter hit & 2 DC hit” are required • if we request 10k tracks for 1 wire at least, 90 hours are necessary DC status, 18.07.2007, je
cosmic ray in the COBRA field • event examples μ+ : 746MeV/c μ- : 607MeV/c DC status, 18.07.2007, je
0 9 1 10 2 11 3 12 4 13 5 14 6 15 7 16 8 17 DC trigger (Michel)== energy and resolution calib. • The definition of the standard Michel trigger : • just requiring the # of hit sector ≥ 4 , does NOT care “inner/outer” e+ inner outer • optional trigger : • (1)standard trigger + 1 hit in the “outer sector” • (2)standard trigger + TC hit (bar & fibre) DC status, 18.07.2007, je
momentum spectra (standard trigger) DC status, 18.07.2007, je
momentum spectra (optional trigger) DC status, 18.07.2007, je
Control of DC geometry • 2 print crosses measured relative to reference bolts in mech. Workshop • Same in COBRA by survey group • On the platform • Without end cap • (next days !) • Without COBRA DC status, 18.07.2007, je
photos DC status, 18.07.2007, je
photos DC status, 18.07.2007, je
Backgrounds • HV units, disappear with linear regulator for low supply • “Front end program” not polling but online time calibration • Up-down negligible with better up-down print grounding • print ground to metallic cover of Carbon support • Al contact between frames from up support to down support • Rate (temperature) dependence of DRS calibration next Chip DC status, 18.07.2007, je
Data reduction reject cells a) peak to peak of anode sum < 2*threshold in time window b) 2 neighbors with peak to peak of anode sum < 2*threshold in time window DC status, 18.07.2007, je
Second optimistic migration possibility to COBRA : today • Realistic migration to COBRA : Thursday, Friday • Aquarium • a) flushing gas (5 hours) + HV (last 3 hours of gas flushing) • b) measurement and analysis (2 hours ) • c) flush He in Aquarium (3 hours) • d) eventually measurement and analysis( 2 Hours) • total of 12 Hours • Support • a) flushing gas (7 hours) + HV (last <3 hours of gas flushing) • b) measurement and analysis of previous run (3-6 hours 40000 events) • c) change connection and cosmic Scintillator position(1 hour) • Total of 11 hours for the first after Aquarium run, < 7 hours for the others ( without repair) DC status, 18.07.2007, je
Finish testing on support • Transport and insert in COBRA • Measure geometry by survey group • Cabling in pE5 2 days • Test DAQ complete system • Cosmic without COBRA field (alignment) • Cosmic with COBRA field (when COBRA on) > 4 working days DC status, 18.07.2007, je
End DC status, 18.07.2007, je
photos DC status, 18.07.2007, je
photos DC status, 18.07.2007, je