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 2/22/2019 DC_status,Je

HV supply < 100 V oscillations  OK 8 x 2 channels for dec-run Tests Noise – filter Optimize ramping Capacitors +DC charge loading Recovery, isolators polarizing time 2/22/2019 DC_status

preamplifier noise and DRS Input attenuation s of 400 first DRS channels [mV] Anode number 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) 2/22/2019 DC_status

DC Current-slit behavior OK Noise important Max current at 1700 V : ~5 mA May be 1780 necessary (first run 2000 V : 60 mA) 2/22/2019 DC_status

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 2/22/2019 DC_status

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 2/22/2019 DC_status

Near wing frame, protection longer new print Near wing frame, protection longer 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 2/22/2019 DC_status

gas regulation and DC tightness [Pa] [Pa] gas regulation and DC tightness Pressure sensors S1 S2 Flux in out DC‘s Dpf Dp manifold [Pa/(cc/min)] Dp/(Flux in+ Flux out) Consistency Dp/(Flux in+ Flux out) constant Dpf << Dp (S1+S2)/2 2/22/2019 DC_status

8 DC connected to manifolds Stabilize at or Ok if not 12 min Ln Dp Tightness 4 good 2 not so good 2 bad 8 DC connected to manifolds Stabilize at or Ok if not (not consistent with viscosity air-He) DC‘s (S1+S2)/2 Flux out (with Flux in = 50 cc/min) 2/22/2019 DC_status

Diffusion of He through Mylar 12 mm 1/2 atm 16x1450 cm2 4.6 cc/min 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 2/22/2019 DC_status

He-C2H6 Ratio dependence 1850 V 43% He, 50% He, 55.6% He .79 1.03 1.3  < 2 % stability, reproducibility 2/22/2019 DC_status

Sensor of He fraction in He-C2H6 mixture Gas system in Lab Understand and calibrate system perfectly Calibration of He content sensor or better suited sensor 2/22/2019 DC_status

Cable duct  radius – 2 to 3 mm Modify shape of C – supports  2.5 mm 4 Cable duct  radius – 2 to 3 mm Modify shape of C – supports  2.5 mm adapt new manifold to 1) 2/22/2019 DC_status

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 correlated anode up, anode down, cathodes) DC NaI DC 2/22/2019 DC_status

Tokio Scintillators Cosmic m COBRA Xe NaI DC 2/22/2019 DC_status

Schedule beginning 2007 Cathode + Hood Anode ( new prints) Feb 01 Feb 02 Mar 1 Mar 2 Apr 01 Apr 02 Mai 01 Mai 02 Jun 01 Jun 02 Jul 01 Cathode + Hood   4 weeks Anode ( new prints) 12 weeks construction 13 weeks (Tightness) Lab test Sr90,Mn54,cosmic, all triggered mount on support test on support (Sr90 ,self trigger, Mn54 trigger) (triggered cosmic m’s ’ ?) mount in Cobra test in COBRA (Sr90 for ,self trigger) (triggered cosmic m ‘s ?) „N bag“ 2/22/2019 DC_status

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 2/22/2019 DC_status

2/22/2019 DC_status