35t TPC FEMB Status 20160302 - 35t - B.Kirby Major TPC FEMB - PowerPoint PPT Presentation

35t TPC FEMB Status 20160302 - 35t - B.Kirby

Major TPC FEMB Problems ● “High Noise” state - noise levels are unstable ○ Have some probability of going into a “high noise” state that makes data unusable ○ Need to identify best method of recovery, power-cycling works but may be risky ● Noise levels are generally large ○ Raw noise levels generally around 2000-2500e- ● Number of bad channels has increased due to hardware problems ○ FEMB03, FEMB14 producing corrupted data for ASICs 0-3 ○ FEMB09, FEMB10 off due to excessive current draw ○ 7 ASICs turned off after first power cycle following cryostat filling ○ Total # of bad channels = 550

Pedestal ENC > 20000 e- “High Noise” State Affects entire detector, never occurs on single FEMB RMS >100 ADC Oscillatory signal 3

Feb 26 Start of High-Noise State in Data Run 13159 event 3437 recorded start of high noise state Something simultaneously saturates nearly all channels, high noise starts 4 ~300us after

Current Draw in Normal and High-Noise State LV ASIC current draw in normal state: LV ASIC current draw in high-noise state: RCE00 = 1.136A FEMB00 - 1.145A RCE01 = 1.133A FEMB01 - 1.140A RCE02 = 1.12A FEMB02 - 1.12A RCE03 = 0.993A FEMB03 - 0.998A RCE04 = 1.09A FEMB04 - 1.09A RCE05 = 1.03A FEMB05 - 1.03A Current ~100mA lower on ASICs RCE06 = 1.13A FEMB06 - 1.13A during high-noise state, turning RCE07 = 1.03A FEMB07 - 1.03A them off generally stops the noise RCE08 = 1.03A FEMB08 - 1.04A APA3 FEMBs usually the cause, RCE09 - OFF FEMB09 - OFF, but not always RCE10 = OFF FEMB10 - OFF, RCE11 = 1.02A FEMB11 - 1.03A RCE12A = 1.02A FEMB12 - 0.900A RCE13A = 1.02A FEMB13 - 0.898A RCE14A = 1.02A FEMB14 - 0.913A RCE15A = 1.18A FEMB15 - 1.04A 5

High Noise State Recovery ● Need to identify best method of recovering from high-noise state ● Power cycling ASICs with lowered current draw generally fixed problem ○ Sometimes need to power-cycle all ASICs ○ However, power-cycling ASICs may be risking at cryogenic temperature, see FEMB09/10 ● Wire-bias trick ○ Likely inducing large transient that saturates amplifiers ○ Does not seem to work consistently ● Resetting / reconfiguring ASICs ○ This does not seem to work ○ Has some probability of causing the high-noise state ● Waiting - the high noise state seems to stop on it’s own on ~2 hour timescale ○ Possibly due to another saturating event?

Noise Measurements ● Noise during “normal” operation is relatively high ● Tried increasing ASIC gain and shaping time on Feb 26 to improve S/N ● Currently running with 14mV/fC gain, 3us shaping time ● Run 13851 recorded Feb 29, ~4300e- ENC raw, ~2500e- ENC after 11kHz subtracted Raw Noise Vs Channel # Run State Collection Induction Collection Noise Induction Noise Noise (ENC) Noise (ENC) 11kHz Subtracted 11kHz Subtracted 13851 Normal running 3200 e- 4300 e- 1600 e- 2500 e-

Feb 17 “Turn Everything Off” Test - Noise Increases Run # ELOG System State Collection Noise (e- Induction Noise ENC) (e- ENC) 11481 5927 “Everything off” 2310 4070 11484 5929 Turned on purity monitor, RTD, PC4 2340 4120 11487 SSPs turned on 2630 4430 11488 CCU and PTB turned on 2640 4490 11492 Wire-bias ramped, “high noise” state 11493 ASICs power-cycled, “high noise” removed 2690 4620 11494 Drift field bias ramped up 2870 4810 5936 Cameras back on 8 11504 5940 “Everything on” 2940 4780

Feb 22 Single FEMB Runs Noise Measurment in ENC Collection / Induction ENC After 11kHz Subtraction FEMB 1us 2us 3us Run ENC @ 1us ENC @ 2us ENC @ 3us FEMB00 12402 12404 12403 FEMB04 1020e- / 1880e- 1070e- / 1700e- 1160e- / 1740e- FEMB01 12408 12410 12411 FEMB05 1000e- / 1850e- 1050e- / 1830e- 1080e- / 1710e- FEMB02 12414 12413 12412 FEMB06 980e- / 1650e- 1000e- / 1570e- 1020e- / 1670e- FEMB03 12415 12416 12417 FEMB07 1020e- / 1840e- 1080e- / 1780e- 1100e- / 1850e- FEMB04 12420 12419 12418 ● Single FEMB study done with wire bias + FEMB05 12421 12422 12423 drift field off , other systems on (?) FEMB06 12426 12425 12424 ● Single FEMB noise ~1000 to 1100e- ENC FEMB07 12427 12428 12429 on collection planes, 1600e- to 1900e- ENC on induction planes 9 ● Can this be lowered?

Noise Measurements - APA0 sees “Ringing” “Ringing” packet: ~28kHz This is a sign that large noise seen on channel inputs is partly due to external pickup

Example Collection Channel Waveform with Track Signals Noise and Cosmic Track S/N Collection plane signals clearly visible Waveform Vs Channel After Correlated Noise Subtraction Waveform Sample # Example Induction Channel Waveform with Track Signals Online Channel # Induction plane signals lost in the noise

Bad Channel Status ● Number of bad channels have increased due to three problems: ○ Corrupted data on FEMB03 ASICs 0-3, FEMB14 ASICs 0-3 (might be recoverable) ○ FEMB09, FEMB10 power draw off ○ 7 bad ASICs following cryogenic power cycle (try running at 900mV baseline) ● Total number of bad channels = 550 ○ Includes individual bad channels, does NOT include broken wires

Summary ● Understanding FEMB instability and large noise levels is the top priority for cold electronics ● Significant improvement in noise levels due to choice of ASIC settings ○ However noise levels are still high, evidence of pickup from non-TPC related systems ● Propose another “everything off” test to pin down noise sources, 1 day ○ Turn everything non-TPC related off, take data with single FEMB and identify best possible noise level (pumps probably can stay on) ■ Vary FE-ASIC settings to see if improvement is possible ○ Turn on FEMB ASICs on one APA + wire-bias + drift field ○ Take ~4 hours of cosmic data ■ Determine if signal to noise is “acceptable”, improved over normal running mode ■ Measure how often “high-noise” state occurs ○ Add additional system components and measure changes in noise levels ● Reducing noise levels is valuable as it will improve proposed detector studies, and connection between noise levels and system instability is not clear