High Voltage Tests At CERN Heng-Ye Liao, Francesco Pietropaolo, Francesca Stocker, Kevin Wood HV Consortium Meeting 03/21/2018
Motivation ● Q u i c k t u r n a r o u n d t e s t s o f h i g h v o l t a g e c o mp o n e n t s f o r p r o t o D U N E ● D e v e l o p me n t o n h i g h v o l t a g e d i a g n o s t i c s t o o l s 2
Test Setup Ground Planes Ground Planes High Voltage Cable High Voltage Cable ● Heinzinger Power Supply ● No RC filter in the load 10 cm drift gap I-beams for testing I-beams for testing ~ 100 kV Field Cage Profiles Field Cage Profiles ● All FC profiles are at same potential TOP View 3
Monitoring Instrumentation View port for View port for LED illumination LED illumination Rpi Camera Rpi Camera Antenna Antenna Ground Planes Ground Planes ProtoDUNE Ground Plane ProtoDUNE Ground Plane Pick-off Board Pick-off Board Side View 4
High Voltage Test in Air HV Activities at 100 kV in air 5
Simplified Sketch of Cryogenic Setup 1.19bar Recirculation-purification purifer Heat exchanger Circuit ● LAr Consumption: ~4 l/hr Gas LAr 4l/h ● ~2 days to empty the inner vessel Purifed LAr HV-T est 1.22bar Setup Inner Vessel 200 l Drawing by Pure LAr Francesca Outer Thermal Bath 6
Discharge During HV test @ 105 kV - Discharge around the HV cable - Bubble formation after discharging → Live stream at CERN: http://icab04.cern.ch:18160 7 (See details of connection in the backup slides)
Ramping Up Discharge on the HV Cable 147 kV 142 kV 55 kV 60 kV 03/16/2018 Note: Need to scale by ~1.58 on current & voltage readout from Heinzinger 8 (calibration issue)
Discharge After 147 kV Video Credit: Kevin 9
Typical HV Discharge Event from the HV Cable GP signal saturation because of 10 V TVS diode in the circuit Software Credit: Kevin 10
Typical HV Discharge Event from the HV Cable Software Credit: Kevin 11
Candidates of the “I-beam Events” 120 kV 110 kV 100 kV - Few candidates of the “I-beam events” from the Heinzinger readouts - No time-correlated ground plane events associated with these candidates 12 p.s. Need to scale by ~1.58 on Heinzinger voltage & current
Status ● Refill LAr on March, 09, 2018 ● Record GP & Antenna traces after 03/12/2018 ~12:00 ● Stable running HV at 100 kV Observed no HV activities associated with I-beams ● HV at 147 kV Observed discharge on the HV cable only ● HV at 110 kV 3 candidates of “I-beam events” on Heinzinger, no time-correlated GP traces ● Observe cosmic-ray events in the test setup -Different polarity of GP traces, no time-correlation with Heinzinger -Ballpark calculation of the signal size 5 tracks of cosmics are ~ 10 mV signal in the GP DAQ? (Assuming µ as MIP, dE/dx~ 2.1 MeV/cm ) ● Currently running at 120 kV ● Plan to go higher 13
Backup 14
E-Field Simulation for the Orientation of the FC Profiles (Bo) 15
Live Stream of the HV test at CERN ● Connection Inside CERN: - Open VLC player Media > Open Network stream > Type http://icab04.cern.ch:18160 ● Connection Outside CERN: - Make an SSH tunnel through lxplus.cern.ch ssh -v -N -L localhost:18163:icab04.cern.ch:18160 -p 22 USERNAME@lxplus.cern.ch - Open VLC player & type http://localhost:18183 16
Events with Different Polarity & No Time Correlation with Heinzinger 17
Simplified Electrical Circuit of Ground Planes Instrumentation Ground Plane 50 kΩ 10 V TVS 720 kOhm DAQ Diodes resistor 39 V MOV 250 kΩ [1] [2] [0] Housing in a Pomona box [0] Circuit in the cryo [1] Circuit outside cryo to limit the input voltage to ±10 V [2] Voltage Divider to handle the signal size 18
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