CSC Trigger Primitives Test Beam Studies

1Endcap Muon meeting: CMU, Oct 19, 2003 J. Hauser UCLA

CSC Trigger Primitives Test Beam Studies

Main Test Beam 2003 Goals:• Verify the peripheral crate electronics (mainly DMB/TMB) are

ready for production.

• Complete a trigger electronic chain test from CSCs all the way to the Track-Finder trigger.

Subsidiary Goals:• Find and fix hardware/firmware bugs and annoyances.

• Find and fix software bugs and annoyances.

• (Re-)demonstrate proper triggering and DAQ readout.

• Shake out new OO software package.


Beam Test Setup

Peripheral Crate2 DMB, 2 TMB1 CCB, 1 MPC

FED crate 1 DDU

PC

TTC crate

DAQ Data

Trigger primitives

S1 S2 S3

beam

CSC 1 CSC 2

Track finder Crate

TRIDAS


Beam Test Setup

/ From front

end cards

2 TMBs and DMBs

MPC

CCB + TTCRx

• 2 CSC’s, all on-chamber boards• Peripheral crate• Track Finder• CMS readout board• Up to 80K events read out in 2.6s

spill


Typical Muon Event (CSC1 tilted)


2003 Test Beam Chronology• Phase I – structured beam

• May 23-June 1• ALCT timing tests• CLCT and TMB studies• High-rate tests

• Phase II – unstructured beam• June 13-28• CLCT and TMB studies• Low-rate and high-rate tests

• Phase III – additional structured beam• September 18-22• Trigger optical link data transmission tests (MPC to SRSP)


Phase I Results• Optimal timing found• Fairly high efficiency (~98-99%) achieved• Peripheral crate system basically working as

desired• Chamber angle, HV, threshold scans


Structure repeats during 2.6 s spill length

48 bunches25 ns bunch spacingbunch width 3-5 ns

SPS orbit period

1.2 s

23 s

2003 Synchronous Beam Structure


Bunch Structure, ALCT Delay Tuning

BX efficiency vs. ALCT delay setting 0-31 ns

Chamber 1 Chamber 2

Expect muons in 48 out of 924 bx verified by CLCT bxn from data


BX Distributions With Optimal Anode Delays

Note logarithmic scale

Cathodes: • Data mostly in 3 bx

(no fine time-adjustment possible)

Anodes: • Data 98.7% in 1 bx

(after fine time-adjustment)

Chamber 1 Chamber 2


CLCT Positions• Relative position

of key half strip from CLCTs from chamber 2 vs. Chamber 1

• Note: Chamber 1 is vertically higher than Chamber 2 (thus the offset in position).

Zoom


LCT Efficiency vs. Comp. Thresh.• HV=3600v


LCT Efficiency vs. HV


Trigger Rate Tests

Expected LCT rate at LHC < 25 KHz (ME1/1)

data consistent with dead-time = 225 ns

Chamber #1 CLCT

0

500

1,000

1,500

2,000

0 500 1,000 1,500 2,000 2,500 3,000

Beam Intensity (KHz)

CL

CT

Ra

te (

KH

z) SLHC (10xLHC) SLHC

(10xLHC)


Number of LCTs (Run 529)

Cathodes show ~4% 0-LCT events

• Early run, before timing tuned

Anodes show ~10% 2-LCT events


Look at 2-ALCT events

Differences:• Bunch crossing counter

• Wire group


An Event w/ 2 Chamber 1 ALCTs

• Anode hits satisfy 6-hit requirement in 2 adjacent key wire groups


Patterns and Quality in ALCT and TMB Logic xxx__ ly 0 _xx__ ly 1 __x__ ly 2 __xx_ ly 3 __xxx ly 4 __xxx ly 5

ALCT Pattern

TMB Patterns

x___ x___ xx__ _x__ _xx_ __x_

pattern 1

_x__ _x__ _x__ _x__ __x_ __x_

pattern 2

x___ x___ xx__ _x__ _x__ _x__

pattern 3

_x__ _x__ _x__ _x__ _x__ _x__

pattern 4

__x_ __x_ _xx_ _x__ _x__ _x__

pattern 5

_x__ _x__ _x__ _x__ x___ x___

pattern 6

__x_ ly 0 __x_ ly 1 _xx_ ly 2 _x__ ly 3 xx__ ly 4 x___ ly 5

pattern 7

Patterns:

Qualities for ALCT and CLCT:Quality=3 6 layers in pattern

Quality=2 5 layers in pattern

Quality=1 4 layers in pattern

Quality=0 <=3 layers in pattern


Half-/Di-Strip CLCT PatternsNominally phi_b=0, but small tilts, esp. chamber 2


CLCT Quality, Pattern vs. Phi_b

Phi_b (tilt)

Quality (layers)

Pattern


Test Beam Periods 2&3• Timing-in procedures improved & documented• Very high efficiencies achieved

• Highest trigger efficiency of 99.9% required low rate (few kHz)

• 2-chamber “excellent event” (CFEB, CLCT, ALCT) efficiency limited to 99% due to CFEB timing

• Improved scans taken:• Angle scan

• HV scan

• Comparator threshold scan

• Pattern requirements scan

• Logic scope read out on most data

• True time history of LCTs read by SR/SP input FIFO (see Darin/Alexei talks).


CLCT Pattern RequirementsExample – “excellent event” (2xCFEB, 2xCLCT,

2xALCT) percentages:

Di-strip Pretrig. Layers

Half-strip Pretrig. Layers

Pattern Layers

Run # Excellent Event Eff.

(off) 4 1 1133 98.9%

4 4 1 1134 98.8%

3 3 1 1132 98.0%

3 3 3 1131 97.9%

4 4 4 1126 94.7%

(off) 4 4 1119 94.7%

(off) 3 3 1120 94.7%

(off) 2 2 1121 92.6%


Digital Comparisons LCTs vs. Simulation• Simulation “DIGIs” start

from raw hit data• ORCA classes used

• Added modifications to reflect test beam TMB firmware (due to FPGA limitations)

• In principle, tests ALCT, CLCT, and TMB logic.

• So far, mainly a good debugging tool for simulation

• Present level of ALCT disagreement:

• ALCT Wire Group: 1.75%/1.99%

• ALCT Quality: 0.15%/0.41%

• CLCT disagreement ~10% (see plots on right)


Comparison of LCTs to Simulation• ORCA simulation has some shortcomings and

needs updating:• Pretrigger # of layers is still hardcoded.

– Was varied during test beam data-taking

• No drift delay in ORCA after pretrigger – just uses any hits within 4 bx of some reference bx.

• ORCA logic selects highest quality only, doesn’t prefer half-strip patters to di-strip patterns as per hardware.

• Simplification for test beam TMB allows only 1 CLCT per CFEB

• These are being addressed right now.


Comments on Results• Timing in the system takes effort but getting

easier (~2 weeks -> 1 week -> 2 days)• Almost everything can be done remotely with software.

• Procedures must really be streamlined to deal with 468 chambers…

• When timed in and experts are present:• Electronics hardware is reliable (nothing flaky).

• Data quality is terrific, esp. compared to other CMS subsystems…

• Trigger and readout efficiencies are very good.

• It will be hard work to streamline for 468 chamber operation…

CSC Trigger Primitives Test Beam Studies

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