LHCb VELO Testbeam

at Fermilab

Jianchun Wang

Syracuse University

Jianchun Wang 2

Track Data Format

C: Pixel Track Event for VELO

1. Magic cookie (01 02 03 04) I*42. Length of the block

I*4 3. Block type (7) I*44. Trigger event ID

I*45. Matched VELO event ID I*46. Distance from trigger jump I*47. Number of tracks

I*48. Number of hits (Track 1) I*49. Chi2 of fit F*410. Projected X at DUT

F*411. Projected Y at DUT

F*412. Track slope X F*413. Track slope Y F*414. Projected X error at DUT F*415. Projected Y error at DUT F*416. … ( Track 2)17. FF FF FF 00 I*4

A: Raw Track

1. Magic cookie (01 02 03 04) I*42. Length of the block

I*43. Block type (6) I*44. Number of hits

I*45. Tbdb ID ( Hit 1)

I*46. Chip ID

I*47. Local X

F*48. Local Y

F*49. Expected X resolution

F*410. Expected Y resolution

F*411. … (Hit 2)12. FF FF FF 00 I*4

B: VELO Alignment

1. Magic cookie (01 02 03 04) I*42. Length of the block

I*4 3. Block type (8) I*44. Number of VELO sensors I*45. X offset of sensor 1

F*46. Y offset of sensor 1

F*47. Angle around X axis of sensor 1

F*48. Angle around Y axis of sensor 1

F*49. Angle around Z axis of sensor 1

F*410. …11. FF FF FF 00 I*4

For pixel alignment: AAAAAA…

For VELO study: BCCCCC…

Jianchun Wang 3

Event Matching Between Pixel and VELO

There are fake trigger or trigger inefficiency, that are different in the two systems. Showing up in data ~ few counts difference over the whole run (~50K triggers). To determine and correct this trigger jump we rely on matching between VELO hit and

pixel track. Out of 115 runs 81 have this problem, totals 349 jumps. For some studies events around the jump should be excluded.

Accu. Number of VELO Hits

Trig

ger

Cou

nt O

ffset

Best match

Offset

pix_090420_111844

Jianchun Wang 4

Pixel Trigger Issue

The pixel trigger ID should be continuously incremented number starting from 0.

15 files with pixel trigger issues that the trigger number are not continuous.

In 3 runs, few trigger pockets were not sent out, resulting a jump of one count or few. This does not affect event matching between pixel and Velo systems.

In 13 runs, there were fake trigger pockets sent out (total 63 times). Because the trigger counter has cycle of 4096. Count smaller than in the previous event results in an increment of 4096. This was corrected manually.

Run pix_090420_094446

Pixel Trigger ID (100 bins)

Before After

Jianchun Wang 5

Summary Of Status

Pixel and VELO events are matched in all runs. Wrongly assembled VELO events are fixed. We need to regenerate date

files of these runs.

Pixel alignment is good enough for many studies. More precise alignment is on the way.

Tracks of reasonable alignment are generated. Tool is written to handle tracks.

Noise, efficiency, resolution, and TELL1 algorithm cross-checking are on-going.

Jianchun Wang 6

Data Sets

Detector Angle HV Setting Stations ADC

90 Lars90 Kazu

90, 20, 40 Chris P2V1 20.15 - 20.18 9ChrisLarsChrisLarsChrisLars

500 Lars500 + scan Chris500 + scan Kazu

8 500 + scan Kazu 5 P3V1 24.07 - 24.18 514 500 + scan Kazu 4.5+thin P4V1 26.06 - 26.15 630 500 + scan Kazu P5V1 26.19 - 27.09 77

500 + scan Kazu500 Chris

4 500 Kazu P5V3 27.20 - 27.22 99KazuChris

23

26

88

106

First

1

16

20

21.16 - 21.18

22.07 - 23.14

27.11 - 27.18

28.09 - 28.22

Time Range (date.hour )

21.08 - 21.10

21.12 - 21.14

19.13 - 20.11

VELO Pixel

0

8RF bottom

4

0RR

bottom

4

12

500

5

2-bit

binary

90

90

90

8RR top

RR middle

0

Geom Config

P2V2

P2V3

P1V1

P2V4

P2V5

P5V2

P5V4

Jianchun Wang 7

Residual On the 5th Station

Measurement – Track Projection (mm)

Num

ber

of E

ntrie

s (A

rb.

Uni

t)

Ncol > 1

Nrow > 1

Ncol = 1

Nrow = 1

DifferentScale

Resolution (mm)

ResidualRemove

track

Ncol > 1 7.6 5.8

Ncol = 1 120.0 119.8

Nrow > 1 8.3 6.6

Nrow = 1 12.7 11.7

Binary readout5 pixel stations

Simulated through iterations track proj. error ~ 4.9 mm

Jianchun Wang 8

Track Probability Issue

Simulationparameters

N Row N Col

1 >1 1 >1

Probability 0.759 0.241 0.978 0.022

Resol (mm)

11.7 6.6 119.8 5.8

Type Z (mm) X (10-3 X0)

X-pixel -450 9.5

Y-pixel -444 9.5

VELO 0 6.4

Y-pixel 317 12.5

X-pixel 514 9.5

Y-pixel 520 9.5

Non-gaussian

Prob (c2, ndof)

Tra

cks

(arb

. U

nit)

Exclude Ncol = 1

With multiple scattering

Prob (c2, ndof)

Tra

cks

(arb

. U

nit)

Expect

Seen Uniform dist for Ncol=1Gaussian for the rest

Jianchun Wang 9

Tracking Error

Multiple scatt.

Include Ncol=1

Residual (mm)

sx sy

5 stations

No No 7.47 6.32

No Yes 7.42 6.30

Yes No 7.73 6.53

Yes Yes 7.69 6.51

Multi-ccatt. only 2.07 1.74

4 stations

Yes No 7.71 7.72

Yes Yes 7.68 7.68

Multi-scatt. only 1.85 1.85

5 pixel stations

Tracking Error from Pixel (mm)

Y

X

Log

( nu

mbe

r of

tra

cks

)

Calculated without multiple scattering

Multiple scattering contributes 1.7-2.1mm to track projection error.

One can select events of better tracking error.

Measurements of Ncol=1 improve track projection precision, although distort the track probability distribution.

Jianchun Wang 10

Look at R/ F Data

X ( mm)Y

( m

m)

Effective Track Angle (degree)

Signal (ADC)

Matched Hits

We took data at nominal 0, 4, 8, 12 degrees rotated around horizontal axis.

The effective angle is smaller due to concentric strips.

Pixel coverage

Jianchun Wang 11

Effective Track Angle (Degree)

Per

cent

age

of H

itsCharge Sharing (I)

Cluster Size

All pitches & track angle

Seed threshold = 6 ADC ~ 9.6 Ke

Side threshold = 3 ADC ~ 4.8 Ke

Strip pitch (40, 50) mmNstrip = 1 Nstrip = 2

Nstrip = 3

R sensor of R/ f pair

Range: angle0.5

Jianchun Wang 12

Charge Sharing (II)

Pitch ( mm)

40 – 5050 – 6060 – 7070 – 8080 – 90

90 – 100

Effective Track Angle (Degree)

(Nst

rip >

1)

/ N

tota

l (%

)

R/f data is split into 1 of angle & 10 mm of pitch sub-samples.

Sub-samples of 0, 3, 7 and 11 are with reasonable large statistics.

Strip Pitch (mm)(N

strip

> 1

) /

N to

tal (

%)

Angle ( )-0.5 – 0.52.5 – 3.56.5 – 7.5

10.5 – 11.5

Jianchun Wang 13

Velo Resolution Measurement

s<Resid = 19.2 mm

<strk> = 8.0 mm

Nevent = 175K

Rvelo – Rtrack (mm)

sResid = 18.0 mm

<strk> = 5.1 mm

Nevent = 12.5K

Rvelo – Rtrack (mm)

Trk error = (pixel)1.85mm (multi-scatt.)

<strk> = quadratic average over all trks

Tracking Error from Pixel (mm)

Error < 6 mm

To improve tracking precision one has to sacrifice statistics.

Jianchun Wang 14

Resolution vs Pitch

R sensor of R/ f pairV

elo

Hit

Res

olut

ion

(mm

) Preliminary !.Angle ( )- 0.5 – 0.52.5 – 3.56.5 – 7.5

10.5 – 11.5

Strip Pitch (mm)

Seed threshold = 6 ADC ~ 9.6 Ke

Side threshold = 3 ADC ~ 4.8 Ke

Tracking projection uncertainty removed from resolution.

Tracking precision is determined for each point ( ~ 4.7–5.4 mm).

Error bar represents only statistic error.

Linear charge weighting, eta-correction not applied yet.

Jianchun Wang 15

Tracking Precision

For each track the projections on Velo and projected errors in both X and Y directions are calculated using the corresponding pixel resolutions. R and error in R is calculated from X/Y.

For each sample (point), the projection error is quadratically averaged over all tracks used.

Projection error due to multiple scattering is ~1.85 mm obtained from simulation.

The alignment error is to be determined.

Angle ( )- 0.5 – 0.52.5 – 3.56.5 – 7.5

10.5 – 11.5

R E

rror

Fro

m T

rack

Pro

ject

ion

(mm

)

Strip Pitch (mm)

Jianchun Wang 16

Resolution vs Track Angle

Pitch ( mm)

40 – 5050 – 6060 – 7070 – 8080 – 90

90 – 100

Effective Track Angle (Degree)

Vel

o H

it R

esol

utio

n (m

m)

Effective track angle is determined in plane perpendicular to the strip.

Sub-samples of 0, 3, 7 and 11 are with reasonable large statistics.

Other angles are due to concentric strip, thus with small amount of hits.

Jianchun Wang 17

The Eta Curve

Track Hit Fraction

Center of Strip N Center of Strip N+1

Only Strip N has Charge

Clu

ster

Fra

ctio

n

Only Strip N+1 has Charge

( )

i

Cluster Fraction

ADC i N

ADC

One strip shift due to tracking precision

All pitches & angles

Nstrip = 1 removed

Jianchun Wang 18

The Eta Curves Of Small Pitches

Clu

ste

r F

ract

ion

Track Hit Fraction

Angle=0 Angle=3

Angle=7 Angle=11

Pitch = (40-50) mm

Nstrip = 1 removed

Jianchun Wang 19

The Eta Curves Of Small Pitches

Clu

ste

r F

ract

ion

Track Hit Fraction

Angle=0 Angle=3

Angle=7 Angle=11

Pitch = (40-50) mm

Cluster fraction=0 or1 correspond to nstrip=1, indicating how charge sharing varies with hit position.

Jianchun Wang 2020

Uniform Irradiation:6 VELO year eq.Useful for resolution, efficiency & S/N vs pitch, angle (x-axis rotations)

Uniform Irradiation:0 VELO year eq.Useful for resolution & S/N vs pitch, angle (x-axis rotations)

Varying Irradiation:0-6 VELO year eq.Useful for resolution, efficiency & S/N vs. pitch and dose

Jianchun Wang 21

RR Module: Position of irradiation spots

• Beam at the top

• 500V on each sensor

Tell1 8n-in-p

Tell1 5n-in-n

Beamlow irrhigh irr

Bottom

Top

• RR_0deg_Top_latency_0x17_delay_40ns_Kazu_HV500-20090427-081938.mdfRR Files used:

Jianchun Wang 22

Jianchun Wang 2323

N in N

Jianchun Wang 24

Header Height Vs V2.5

Kazu’s setting, at FNAL

header height = 28.48 ± 1.48

T = 23 - 27 °C, Kazu setting

T = 4 - 8 °C, Kazu setting

T = ~ 2 °C, Kazu setting

T = ~ 27 °C, Chris setting

We tried to find out what value V2.5 was during testbeam.

Obtained from one run. Uncertainty of value is about 0.1-0.2. Sigma indicates spread among 64 links.

Chris’s setting, at FNAL

header height = 29.34 ± 1.12

Header height is also affected by T and electronics setting, not just V2.5 alone.

Jianchun Wang 25

Header Height vs Temperature

V2.5 at nominal value

Kazu setting

H = 50.934 – 0.1754 T(C)

VELO Containers

Jianchun Wang 26

Namespace Member Locations

EvtInfoLocation Default Raw/Velo/EvtInfo

VeloErrorBankLocation Default Raw/Velo/VeloErrorBank

VeloFullBankLocationDefaultPedestals

Raw/Velo/ADCBankRaw/Velo/PedBank

VeloFullFPGADigitLocation Default Raw/Velo/FullDigits

VeloProcessInfoLocation Default Raw/Velo/ProcInfo

VeloTELL1DataLocation

ADCsTell1ADCsPedestalsHeadersSimADCsSimPedsSubPedsPedSubADCsFIRCorrectedADCsBitLimitADCsReorderedADCsCMSuppressedADCsCMSNoiseMCMSCorrectedADCs

Raw/Velo/DecodedADCRaw/Velo/RealAndDummyRaw/Velo/DecodedPedRaw/Velo/DecodedHeadersRaw/Velo/SimulatedADCRaw/Velo/SimulatedPedRaw/Velo/SubtractedPedRaw/Velo/SubtractedPedADCsRaw/Velo/FIRCorrectedRaw/Velo/ADC8BitRaw/Velo/ADCReorderedRaw/Velo/ADCCMSuppressedRaw/Velo/CMSNoiseRaw/Velo/ADCMCMSCorrected

VeloClusterLocationDefaultEmulated

Raw/Velo/ClustersEmu/Velo/Clusters

VeloLiteClusterLocation Default Raw/Velo/LiteClusters

Transient Event Store for Emulator

Jianchun Wang 27

Sector ID / Array

Inner strips Outer strips

commentmin max min max

1Strip 0 170 683 1023 (171, 341) inner

& outer stripsIndex 0 170 192 532

2Strip 171 341 1024 1364 (171, 341) inner

& outer stripsIndex 576 746 768 1108

3Strip 342 511 1365 1706 (170, 342) inner

& outer stripsIndex 1152 1321 1344 1685

4Strip 512 682 1707 2047 (171, 341) inner

& outer stripsIndex 1728 1898 1920 2260

Normal data from each hybrid are stored in an array of 2048 = 64x32 elements, indexed by either the electronics channel or the strip ID.

In emulator dummy elements are added to mimic 4 FPGAs. The overall size is 2304 = (64+8)x32.

Before reordering data are stored in the order of electronics channel. And 2x32 dummies are added after each 512=16x32. ( DecodedADC, SubtracedPedADCs, FIRCorrected, and ADCMCMSCorrected).

The pedestal are still stored in an array of 2048 (SubtractedPed).

After channel reordering data are stored in the order of strip ID. For R sensor 2x32 dummies are added after each 512 strips (16x32). For F sensor each sector occupies 18x32 elements with inner strips the beginning of first 6x32 and outer strips the beginning of next 12x32 in the table (ADCReordered, ADCCMSuppressed).