Ground Plane Data Analysis Heng-Ye Liao, Alan Hahn, Cheng-Ju Lin, Sarah Lockwitz 11/08/2017
Setup of Ground Planes Instrumentation TOP-NORTH (TN) TOP-EAST TOP-WEST (TE) (TW) TOP-SOUTH (TS) BEAM PLUG PLATE (BP) VERTICAL-UP (VU) VERTICAL-DOWN (VD) Bottom (BOT)
Simplified Electrical Circuit of Ground Planes Instrumentation Ground Planes [1] [2] instrumentation [0] 4.7 MΩ DAQ 10 V TVS R=5.7 kΩ Diodes 39 V MOV Voltage divider 1 MΩ (Pomona box) Voltage limit of the ground plane DAQ: ±10 V [0]Circuit inside cryo [1]Circuit outside cryo to limit the input voltage to ±10 V [2]Circuit to reduce the high input impedance
Readouts of Ground Planes To ground NI DAQ Signal readout D-sub connector Ground Planes instrumentation 4.7 MΩ DAQ Pomona boxes 10 V TVS R=5.7 kΩ Diodes 39 V MOV Voltage divider 1 MΩ [2] [1] [0] Outside cryostat Inside cryostat
Ground Plane Signals ] V m [ Q A D I N Responses of other ground planes e h t n i e g a t l o V A signal on the vertical-down ground plane d e r u Saturation because of 39 V MOVs s a e M Time since start of this data set [sec] ● Ground plane (GP) signal: Currents across 1 MΩ resistor ● Calibration of signal in the NI DAQ: → 1 mV is equivalent to 1 uA, i.e. 1 V signal in a ground plane ● DAQ sampling rate: 1 kHz ● Signal shape: A signal in one ground plane is negative. Other GPs are capacitively coupled to the field cage (voltage drops on the field cage) ● GP Signal Detection: Any GP trace above 5 mV or below -5 mV ● Event Display: Pre-trigger: 10 msec / Post-trigger: 400 msec
Ground Plane Signals: Multi-Hit Signals A Two-Hit Example: Vertical-Up + Beam Plug Plate An example of a multi-hit event
Ground Plane Signal: “No-Visible-Hit” ● No Visible Hit (NVH) signal: Ground planes response to the activities of the field cage
Ground Plane Signal: NVH Cont’d Toroid always triggers for this type of event. → It indicts that this type of GP event is associated with fast discharge + A time delay signal ● NVH signal with a delay signal (NVHD) ~ 4 sec later
Ground Plane Signal: NVH Cont’d ● Few words about the NVH signals → No viable hit doesn’t mean there is no hit. Simply because the sampling rate of the NI DAQ is not fast enough. Fast discharge 1 µs A typical toroid signal for a fast discharge (Screen grab taken by Alan)
Ground Plane Data Taking ● Before 10/03, we do not have the vertical-up ground plane data, due to the cable connection problem. Vertical-up ground plane was not connected before 10/03
Ground Plane Data Taking ● Before 10/03, we do not have the vertical-up ground plane data, due to the cable connection problem. ● To have better time resolutions on the pickoff signals, we implemented the east, the west, and the beam plug pickoff to the NI DAQ after 10/12. ● We lost data due to the hard drive crash event → Some info can still be extracted from the 35ton e-log ● Data analysis on the ‘good’ data sets (with GP signals+Heinzinger signals)
GP Activities (Steady HV) - Time Distribution Events with no Events with no Ramping up Toroid signals Ramping up Toroid signals from 135 kV to 145 kV from 135 kV to 145 kV After VU was fixed Transition phase (Flushing N 2 gas to the beam plug) Events associated with Events associated with Toroid signals (fast discharges) Toroid signals (fast discharges) We lost the data in this period. Lost data due to the hard drive crash. Lost the communication with the Heinzinger.
Summary of Ground Plane Activities (Steady HV)
Summary of GP Activities (HV Discharges) Event Time Stamp of Trigger Set HV Power Supply Tripping Time Time Stamp # Ground Plane [kV] of Toroid 1 09/23/17-06:06:35.436 PM BP 130 09/23/17 06:06:37.752 PM 09/23/17-06:06:37.--- PM 2 10/01/17-07:03:43.253 AM BP 145 10/01/17 07:03:43.297 AM 10/01/17-07:03:43.--- AM 3 10/02/17-09:50:00.455 AM NVH 120 10/02/17 09:50:01.159 AM - 4 10/13/17-05:36:43.181 PM NVH 130 10/13/17 05:36:43.660 PM 10/13/17-05:36:43.461 PM 5 10/19/17-09:11:34.326 AM NVH 115 10/19/17 09:11:34.801 AM 10/19/17-09:11:34.625 AM 6 10/19/17-07:23:13.355 PM NVH 120 10/19/17 07:23:13.724 PM 10/19/17-07:23:13.510 AM ● Toroid saw HV trips → Fast discharges ● 6 GP events are associated with HV trips 4 are NVH and 2 are BP (+VU) ● Reminder: Before we fixed the VU ground plane (10/03), there were no VU signals. From our observation, BP always comes with VU.
Summary & Outlook ● Ground Planes are sensitive to activities associated with the field cage: Ramping up, HV trips, slow discharges, and fast discharges → Good tools for HV Monitoring ● For the Phase 2 HV test → No obvious single weak spot ● Activities near the top-west and the beam plug-plate area ● Working in progress: -Studying in the time-correlated signals of the east/west/beam Plug pick-offs -Trying to study more for the ‘fast-discharge’ GP events from their traces
Backup
GP Activities after HV Trips Event GP Time Stamp Trigger Power Supply Tripping Time Time Stamp of Toroid # 1 09/15/17-11:37:10:533 AM MH 09/15/17 11:36:52.793 AM - 2 09/17/17-07:33:53:106 PM MH 09/17/17 07:33:17.804 PM - 3 09/17/17-07:34:39:677 PM MH 09/17/17 07:33:17.804 PM - 4 09/18/17-05:10:49:877 PM NVH 09/18/17 05:10:48.868 PM - 5 09/21/17-02:53:43:450 AM BP 09/21/17 02:53:42.309 AM 2017_09_21-02_53_42.--- 6 10/01/17-07:04:14:039 AM MH 10/01/17 07:03:43.297 AM - 7 10/02/17-09:33:03:161 PM NVH 10/02/17 09:33:02.796 PM 2017_10_02-21_33_02.--- 8 10/03/17-03:59:27:376 PM BP 10/03/17 03:59:27.235 PM 2017_10_03-15_59_27.--- 9 10/13/17-05:38:51:808 PM MH 10/13/17 05:36:43.660 PM 0 10 10/19/17-09:14:51:269 AM VD 10/19/17 09:11:34.801 AM 0 11 10/19/17-09:16:45:819 AM MH 10/19/17 09:11:34.801 AM 0 12 10/19/17-07:23:37:475 PM VD 10/19/17 07:23:13.724 PM 0 ● 50% of the GP events are MVHs; 3 associated with fast discharges
GP Activities during Ramping Up Heinzinger HV [kV] ● GP Entries : - BOT: 26 - VD: 1 - NVH: 12 BOT VD NVH
Extracting Info from Pick-offs
Instrumentation of Pick-Offs To GP DAQ B.P. PO to GP DAQ Blocking capacitor Pick-off GP DAQ 10 V [1] Zener Diodes Pomona Box [2] Keithley [1] Not shorting out the Keithley signals → 3kV capacitor (OIM Z5U) [2] Protection on ground plane DAQ → 10 V Zener Diodes (1n758)
Recommend
More recommend
