4/28/2020

Paul Rubinov

Central Fiber Tracker cylinder Discriminator output every 396 nsec for L1 Amplitude signal readout for L3 and offline

AFE and CFT

8 photons VLPC 9 o K 50 fC

DISCR ADC AFE

(x512)

4/28/2020

Overview- talk outline

1) Physics impact 2) AFEII proto boards 3) TriP-t proto chips 4) AFEII-t board design become a project AFE1c replaced by AFEII-t

Different people are working along these 4 paths. This is critical: we have to work on parallel tracks. I will describe our status as of Dzero internal review (Jan 24 th )

4/28/2020

AFE IIt - Cost and Schedule

  

We have a more detailed plan than shown on the previous slide!

Full Project Plan has is fully loaded with costs and resources including peoples names!

We are keeping this plan updated:

  

Experience so far Feedback from the people doing the jobs.

Feedback from Dzero internal review.



The key use of this plan is to spot manpower “holes” and schedule problems.

Al Bross summary slide for cost and schedule at the internal review:

    

No technical issues have been discovered to date that would impact either cost or schedule



Or our philosophy/model regarding Test and Commissioning M&S and manpower costs are understood The contingency (M&S and manpower) in the project plan is understood There is no schedule contingency in the project



4w possible if Vendor Qualification of AFE IIt production is deemed unnecessary Manpower is on board



Except for D0 University Group

 

1) Physics motivation

We have come a long way in understanding the impact of living with AFEI at high L.

Source is talks by Mike Hildreth and Juan Estrada given at the recent AFEII internal review.

What is the cost of living with AFEI?

What are the benefits of adding timing info?

 

1 st a few slides to remind you about AFEI issues.

Slides on MC work to understand how these issues extrapolate to the future, how AFEII/Trip-t can help.

4/28/2020

SVX saturation (2)

800

The problem was studied in the 4 cassette test stand during summer 2004 (DØ Note 4495). Histogram of VRB = 1, Board= 1, Chip=3, Chan=59 Histogram of VRB = 1, Board= 1, Chip=3, Chan=59

450 400 700 350 600 300 500 250 400 200 300 150 200 100 100 50 0 1 10 19 28 37 46 55 64 73 82 91 100 109 118

AFEI 1ch spectrum- no early pulse

127 136 0 145 154 10 19 163 28 172 37 181 46 190 55 199 64 208 73 217 82 226 91 235 100 244 109 253 118 127 136 145 154 163 172

Bond=1, Ave=44.33, StdDev=15.58, Discriminator Counts=0 AFEI 1ch spectrum- 8V, 40ns early pulse

181 190 199 208 217 226 235 244 253 At 30% occupancy (12 crossings) – 4 Hits integrated in pipeline – “Typical” integrated charge on front end » 40 pe – 40% drop in Signal for “triggered” hits on average 4/28/2020

Juan Estrada & Peter Hasiakos

7

Tick to Tick (1)

data from the detector

~20 ADC/pe The pedestal moves up to 1 pe for the high gain pixels, this effect is much more significant in the stereo layers…

4/28/2020 8

Discriminator-ADC crosstalk confirmation in DØ data Special runs were taken to study the effect seen in the test stand using real data. Left plot: shift in ADC counts from nominal peds at 30% discr occupancy (~15 ADC/PE)

SVX Typical channel

Right plot: “typical” ch ped shift as a function of DISCR

SVX

This analysis was done by Avdhesh Chandra from TIFR.

9

Z



bb Event Simulation

• Several samples generated so that the progressive addition of defects could establish a clear trend • Same 1000 Z  bb events used for each sample • Here, 12mb corresponds roughly to 3x10 32 instantaneous Lumi • Samples: – “default” MC, 0 minbias overlay – “default” MC, 12 minbias overlay = “perfect” = “messy” – “realistic” 2004 CFT, 12 minbias – “bad sift” 2007 CFT, 12 minbias – “saturated” 2007 CFT, 12 minbias = “current + messy” = “degraded + messy” = “worst performance” 4/28/2020January 24, 2005 Mike Hildreth – AFE II Internal Review, part 1 10

Saturation Simulation

• Example from Z  bb events – multi-jets plus 12 minbias events – (overestimate of effect) – SVX response begins to saturate (slowly) after 9 p.e., fully saturated above 100pe – Drastic reduction of track multiplicity, number of CFT hits Number of Tracks per beam crossing 4/28/2020January 24, 2005 Number of CFT Hits per beam crossing Mike Hildreth – AFE II Internal Review, part 1 11

b-tagging results

• SVT Tagger per-jet forward-tag efficiencies for all B jets: Sample: Default MC, 0mb Default MC, 12mb 2004 CFT MC, 12mb Bad SIFT MC, 12mb Saturated SVX, 12mb Loose Tag 0.416

0.418

0.404

0.377

0.335

Tight Tag 0.322

0.321

0.318

0.287

0.217

• no discernible difference in backwards tags • up to 40% loss in relative efficiency compared with 2004 MC – AFEII recoups about 75% of this efficiency loss 4/28/2020January 24, 2005 Mike Hildreth – AFE II Internal Review, part 1 12

Time Resolution vs. Occupancy

• For events with 9mb overlaid, timing (z) resolution vs. CFT layer. –

not

ruined by occupancy – outer layers fare better than inner layers, as expected rms = 28.2cm

rms = 28.0cm

PMR: based on VERY detailed MC. Spare slides section has details.

4/28/2020January 24, 2005 Mike Hildreth – AFE II Internal Review, part 1 rms = 26.2cm

rms = 24.9cm

13

More Timing Results

• Timing cut: efficiency vs. rejection for various layers, multi-muon events, 9mb events overlaid (12mb looks similar, slightly worse) Layer 1 Layer 4 Layer 8 (.9,.74) (.9,.32) (.9,.42) – here, “fake” hits are those on found tracks which are caused by another MC particle besides one of the muons 4/28/2020January 24, 2005 Mike Hildreth – AFE II Internal Review, part 1 14

This is the summary slide from Mike H. talk at the internal Dzero review • Current SVX-SIFT AFE will seriously degrade the tracking performance at high occupancies – Saturation may be the dominant effect • under study • Trip-t timing will be useful for pattern recognition – will eventually be limited by multi-hit fibers – outer layers can still benefit even to the highest luminosities – one more handle to combat high occupancies 4/28/2020January 24, 2005 Mike Hildreth – AFE II Internal Review, part 1 15

2) AFEII prototypes



First AFEII prototype is now on the cryostat and taking data.



Next 4 slides show the AFEI problems that AFEII is designed to solve:

  

SVX saturation.

SVX tick to tick ped variation.

DISCR to SVX data cross talk.

Did we fix them? Judge for yourselves.

4/28/2020

AFEII proto: Results

 

Biggest concern is SVX saturation Test: inject huge LED pulse, (7V, 80ns) measure small pulse in the same superbunch

3pe in xing 20 -> readout > 100pe in xing 5

4/28/2020

450 400 350 300 250 200 150 100 50 0 1 10 19 28 37 46 55 64 73 82 91 100 109 118 127 136 145 154 163 172

Bond=1, Ave=44.33, StdDev=15.58, Discriminator Counts=0

181 190 199 208 217 226 235 244 253

AFEII proto: Results



Tick to tick variation in pedestals.



Reset is identical every xing, so there is none.

The sum of data from xing 5, 8, 11 , 14 , 17 , 20 all 64ch from module 1

PMR: I included the individual xing plots in spare slides section, if you wish to check in more detail.

4/28/2020

AFEII proto: Results



Discr to ADC xtalk: it is impossible to make a plot like this with AFEI

Plot from AFEII with 30% discr occupancy.

Compare to AFEI with 32% discr occupancy

4/28/2020

one chan…

AFEII proto: Results



Discr to ADC xtalk: it is impossible to make a plot like this with AFEI

Plot from AFEII with 30% discr occupancy.

Compare to AFEI with 32% discr occupancy

4/28/2020

many chan…

3) TriP-T prototypes



Leo Bellantoni is now leading this effort.

Notes: Cyan = timing out Green = analog out Input: ~30fC@60nS

PMR: Typical scope trace in lieu of picture of Leo in front of scope.

4/28/2020

Summary shown by Leo at the Dzero internal review

 TriP-t is fully fuctional and basically performs as expected  Answers to specific questions: •

t A

-info pulse lowers

A

-info pulse 3 1 / 2 ~ 4% of

t

-pulse; effect on ratio in adjacent fibers ought to be even smaller • • Time pulse gain setable from 2 ~20 mV/ns Time output walk ~44 ps/fC for pulses with ~2 or more p.e.

 Further work is warranted for:   

A

-pulse nonlinearity Optimization of parameter space Documentation PMR: this work is in progress. Currently incorporating feedback from Abder.

4/28/2020 22

4) AFEII-t design



Was on hold until AFEII prototype was up– now starting integrate lessons from AFEII prototypes.



Stefano Rapisarda is joining this effort.

4/28/2020

Summary

 

Recently concluded Dzero internal review

awaiting report/recommendations of the committee



Progress on 4 fronts since last PMG status report: 1.

Physics case has much more detail.

2.

3.

4.

AFEII on the cryostat and taking data. (same cass. as used for AFEI studies by Juan and Peter) Better understanding of TriP-t, studies in progress, needed manpower (Leo) now on board.

AFEII-t engineering help identified and on board (my understanding).

4/28/2020



Spares go here

4/28/2020

SVX Saturation (1)

Event (photons produced) crossing clock 1 crossing=396 ns

Reset at the beginning of the

 Q 1

superbunch.

The voltage at the input amplifiers goes up, but it can hit the maximum. After this point, it can not detect any more photons.

 Q 0 4/28/2020 26

4/28/2020

SVX Discr cross talk

27

Default CFT Monte Carlo

1. Energy Deposition of Geant particles, mapping to fibers, photon generation: 2. Photons ordered by arrival time at VLPC, converted to photo-electrons 3. Total charge calculated, including sampling distribution 4/28/2020January 24, 2005 Mike Hildreth – AFE II Internal Review, part 1 28

Modifications to the CFT Simulation

• The results presented here are based on a new version of the CFT digitization code that includes: – realistic light yields – realistic gain spectra – realistic thresholds – small amount of pedestal noise to simulate threshold spread • (readout thresholds have one setting for 64 channels) This simulation provides the “Current CFT” detector model (One thing missing: tick-by-tick pedestal shifts) 4/28/2020January 24, 2005 Mike Hildreth – AFE II Internal Review, part 1 29

Modifications for High-Lumi CFT

• For purposes of comparison, we have created a “CFT 2007” simulation to model the “un-upgraded” AFE system at high luminosities. This includes: – degradation of CFT light yield by 18% from radiation damage – VLPC gain is lowered by 18% due to high singles rates – (total of 40% signal loss) – higher readout threshold (1.5  2.5 p.e.) • this would be implemented to fight the occupancy caused by the pedestal shifts – SVX pedestal shifts as a function of occupancy • at 32% occupancy (linear with occupancy) – SIFT1: -1pe, SIFT2: -0.5pe, SIFT3: +1pe, SIFT4:+3pe – Saturation of SVX response according to bench tests 4/28/2020January 24, 2005 Mike Hildreth – AFE II Internal Review, part 1 30

• Light yield comparisons for data and MC (with zero-bias events overlayed) – “most probable” values (fit peaks) are similar in both • Detailed understanding of MC/Data differences in light yield spectra are under study – Possible role of SVX Saturation

More plots

4/28/2020January 24, 2005 Mike Hildreth – AFE II Internal Review, part 1 31

Timing Data in CFT Monte Carlo

• Expected correlation (“time-walk”) of low ADC signals clearly seen in simulation • can be corrected on average for better timing resolution for all hits • not done yet for these studies 4/28/2020January 24, 2005 Mike Hildreth – AFE II Internal Review, part 1 32

b-tagging results

• JLIP Tagger per-jet forward-tag efficiencies for all B jets: Sample: Default MC, 0mb Default MC, 12mb 2004 CFT MC, 12mb Bad SIFT MC, 12mb Saturated SVX, 12mb Loose Tag 0.460

0.460

0.442

0.438

0.409

Tight Tag 0.364

0.371

0.360

0.343

0.308

• no discernible difference in backwards tags • up to 15% loss in relative efficiency compared with 2004 MC – AFEII recoups about 75% of this efficiency loss 4/28/2020January 24, 2005 Mike Hildreth – AFE II Internal Review, part 1 33

4/28/2020

AFEII raw data, pipeline 20

4500 4000 3500 3000 2500 2000 1500 1000 500 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 Series1

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AFEII raw data, pipeline 17

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AFEII raw data, pipeline 14

4500 4000 3500 3000 2500 2000 1500 1000 500 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 Series1

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AFEII raw data, pipeline 11

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AFEII raw data, pipeline 8

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AFEII raw data, pipeline 5

4000 3500 3000 2500 2000 1500 1000 500 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 Series1