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MEG DC

MEG DC. HV supply pre amplifier noise and DRS Input attenuation protection in pure He  new print gas regulation, DC tightness, He-C 2 H 6 ratio N bag Calibration schedule. Capacitors +DC charge loading. Recovery, isolators polarizing time. HV supply < 100 V oscillations  OK

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MEG DC

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  1. MEG DC • HV supply preamplifier noise and DRS Input attenuation • protection in pure Henew print • gas regulation, DC tightness, He-C2H6 ratio • N bag • Calibration • schedule DC_status,Je

  2. Capacitors +DC charge loading Recovery, isolators polarizing time HV supply < 100 V oscillations  OK 8 x 2 channels for dec-run Tests Noise – filter Optimize ramping DC_status

  3. s of 400 first DRS channels [mV] Anode number preamplifier noise and DRS Input attenuation For physical big pulse Ratio e+/big pulse const For « edge » big pulse At least rate increas with HV sqrt([6 V on]2 - [6 V off]2) DC_status

  4. DC Current-slit behavior OK Noise important Max current at 1700 V : ~5 mA May be 1780 necessary (first run 2000 V : 60 mA) DC_status

  5. Noise • Much larger than in lab • Much larger than first measurement in PE5 • Fast contribution (see Matthias) already found in HV supply as used in December 2007 run • « slow » component { 1-2 ms) needs more work DC_status

  6. protection in pure He Capacitors, edges, resistance in pure He (< 2% impurities) Imbed elements in Araldit, stable homogenous no temperature effect < 65 0 Threebond white and grey , needs humidity temperature effects already at 55 0 Edges better with next print DC_status

  7. new print Increase distance Carbon frame to HV lines,not to suffer from Threebond „bad“ isolator properties  3 layers with wenn possible HV line in the middle layer Near wing frame, protection longer DC_status

  8. Pressure sensors S1 S2 DC‘s Flux out Flux in Dp/(Flux in+ Flux out) [Pa/(cc/min)] [Pa] [Pa] gas regulation and DC tightness Dpf Dp manifold Consistency Dp/(Flux in+ Flux out) constant Dpf << Dp (S1+S2)/2 DC_status

  9. 12 min Ln Dp 8 DC connected to manifolds Stabilize at or Ok if not (not consistent with viscosity air-He) Flux out (with Flux in = 50 cc/min) (S1+S2)/2 DC‘s Tightness 4 good 2 not so good 2 bad DC_status

  10. C2H6 If diffusion 1/180 negligible If leak ½ .36 cc/min He .09 p/min 16DC,.5 atm  .72 cc/min 40 cc/min  2 % Diffusion of He through Mylar 12 mm 1/2 atm 16x1450 cm2 4.6 cc/min DC_status

  11. He-C2H6 Ratio dependence 1850 V 43% He, 50% He, 55.6% He .79 1.03 1.3  < 2 % stability, reproducibility DC_status

  12. Sensor of He fraction in He-C2H6 mixture • Gas system in Lab • Understand and calibrate system perfectly • Calibration of He content sensor orbetter suited sensor DC_status

  13. 4 • Cable duct  radius – 2 to 3 mm • Modify shape of C – supports  2.5 mm • adapt new manifold to 1) DC_status

  14. Calibration methods • lab aquarium ( DRS + cables for 2 DC) • Mn54 triggered ( 5.9 keV,835 keV photo peak) • Sr90 triggered (< 2 MeV b) • Cosmic m triggered • Lab support ( DRS + cables for 2 DC) (check all channels correctly connected and correlated anode up, anode down, cathodes) • Mn54 triggered (for the temporarily outer DC) • Sr90 not triggered • Cosmic m (triggered ? , complicated) • COBRA (not closed)(check all channels correctly connected and correlatedanode up, anode down, cathodes) • Sr90 not triggered • Cosmic m triggered DC NaI DC DC_status

  15. Tokio Scintillators Cosmic m COBRA Xe NaI DC DC_status

  16. Schedule beginning 2007 „N bag“ DC_status

  17. New anodes  largest time consumer (production rate known) Adapt to N bag conditions, New manifolds in optimized position New hood and cathode frame : Andrei and Nicolai  mostly done Replace anodes on DC04 t0 DC11, construct 8(10) new DC LV+HV cable labeling + mount: Test in aquarium with gas regulation, mount and test on support of modified and new DC Transport, and insert of support with 16 DC and TC+N bag in COBRA Test cabling in COBRA DC_status

  18. DC_status

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