Argonne National Laboratory - Jan 11, 2013

GEM Upgrade GEM Upgrade for for

CMS Forward Muon SystemCMS Forward Muon System

Marcus HohlmannMarcus Hohlmann(an IF-EF liaison for gaseous detectors)(an IF-EF liaison for gaseous detectors)

Florida Institute of TechnologyFlorida Institute of Technology

Argonne National Laboratory - Jan 11, 2013

Instrumentation Frontier Community Meeting – Snowmass Process 2013

MOTIVATION & INTRODUCTIONMOTIVATION & INTRODUCTION

1/11/2013 GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL 2

Premise for CMS GEM upgradePremise for CMS GEM upgrade• CMS was designed with a “hermetic and redundant muon system” –

Joe Incandela, CERN “Higgs Discovery” Event, 7/4/12

• But: CMS currently has the least redundancy in the most challenging muon region, i.e. at |η| > 1.6:

Bakelite RPCs descoped in high-η region (lack of rate capability);

only Cathode Strip Chambers currently present

• Long-term functioning of the muon system into LHC Phase II (beyond Long LHC Shutdown 3) is of vital interest for CMS. Use Phase I to evaluate muon technology for Phase II.

• The high-η muon region in particular will need robust and redundant tracking and triggering at the anticipated increasingly higher muon rates

Additional muon detectors with high spatial and temporal resolution in the high-η endcap region could bring benefits

in triggering, reconstruction, and ID for muons: → GEMs


CMS GCMS GEM EM EEndcap Chambersndcap ChambersThe currently un-instrumented high- RPC region of the muon endcaps presents an opportunity for instrumentation with a detector technology that could sustain the radiation environment long-term and be suitable for operation at the LHC and its future upgrades into Phase II: GEM Detectors

GE3/1

GE4/1

GE1/1in nose of

first Endcap Yoke

CMS Detector

GE1/1 simulation geometry


Integration into CMS Integration into CMS Four superchambers in their final positionon endcap yoke

Installation sequence:

A. Conde Garcia Mounting on yoke disk

Superchamber(Two Triple-GEMs)


Expected Benefits for Reconstruction & TriggerExpected Benefits for Reconstruction & Trigger

M. Maggi (Bari) – GEM Workshop 3

Strip Readout granularity: # GEM strips / # RPC strips (orig. TDR)

Expected gains in momentum resolution at high-pT

Acceptance impact: distribution of 4 muons in H → ZZ → 4µ

Paolo Giacomelli (Bologna) & Markus Klute (MIT) – GEM Workshop 3

1.6<<2.4

for one GEM station

Expected CSC inefficiency at PU=400 due to Cathode LCT - Anode LCT timing mismatching

Staving off looming muon trigger inefficiencies at high-

Simulation

A. Safonov (Texas A&M)


CONSTRUCTION CONSTRUCTION OF FULL-SIZE GEM PROTOTYPESOF FULL-SIZE GEM PROTOTYPES


Evolution - GEM foil stretchingEvolution - GEM foil stretchingCurrent state-of-the-art: Self-stretching assembly sans spacers (CERN)

Readout PCB

GEMs

Drift electrode

Tightening the horizontal screws tensions the GEMs& seals gas volume

Detector base pcb

R. De Oliveira, CMS-GEM/RD51Workshops CERN & U. Gent

Allows re-opening of assembled detector for repairs if needed.

only glue joint in assembly

2012


33rdrd GE1/1 Prototype: GE1/1 Prototype: ““Self-Stretched - Sans SpacerSelf-Stretched - Sans Spacer””

GEM tensioningGEM foil in inner frame assembly

GEM foil with inner & outer frame

Inside of readout board with O-ring sealChamber closed byreadout board with

Panasonic connectorsfor frontend electronics

compact HV divider

Vias for strips sealed w/ kapton

HV noisefilters

-sector with 384 radial

readout strips (12.4 cm long)

base pcb with drift electrode

CERN 2012

No spacers in active volume


GEM active area: 990 mm (220-445) mm Single-mask technology 1D radial strip read-out with 3 8 128 = 3,072 channels 35 HV sectors 3/1/2/1 mm gap sizes Gas mixtures:

Ar/CO2 (70:30; 90:10)Ar/CO2/CF4 (45:15:40; 60:20:20)

Gas flow ≈ 5 l/h

New self-stretching technique has been applied to the full-size CMS GE1/1 GEMs4 prototypes produced & tested at CERN in 2012

1 prototype to be assembled & tested at Fl. Tech in early 20135-8 new final prototypes to be produced for installation of 4 during first LHC long shutdown (LS1)

Full-size GE1/1 Detector PrototypesFull-size GE1/1 Detector Prototypes


Rui De Oliveira

As a lot of dust was released when inserting screws into FR4 frames; CERN has replaced FR4 by PEEK for inner frames.

PEEK is one of the best polymers in terms of:-radiation tolerance-mechanical properties-outgassing-chemical resistance

Use O-ring to seal outer frames to drift plane; removes ALL glue joints

Panasonic readout connector

Readout PCB

GEM foilsOuter frame

Inner frameDrift Board

On-foil protection resistors

Next: No Gluing & PEEK frameNext: No Gluing & PEEK frame

Now PEEK


LHC Long Shutdown 1LHC Long Shutdown 1


GE1/1

GE1/1

ME1/1

ME1/1

ME2/1

YOKE

GE2/1

P5 CAVERN UXC

Prop

osed

to C

MS

Upg

rade

Man

agem

ent

4 GE1/1 GEM chambers in LS1

CMS

Integration & Installation of 2 GE1/1 superchambers = 4 GE1/1 chambers

Measure in situ:•Rates, Background/Noise, Stability, Uniformity, Efficiency•Spatial resolution

– In actual high-η environment – In actual magnetic field

• Split signal to CSC and participate in CMS muon trigger and reconstruction• Install new pre-production trigger motherboards on chambers that overlap with GEMs• Prove that the electronics design is working and demonstrate in situ that we can operate

CSC TMB with GEM input in various operating regimes• Reduce CSC X-Y ambiguity and ghosts• Once we go back to beam operations, demonstrate the above again, this time measuring

muon trigger rates and efficiency with and without GEMs.

Objective: Participate in CRAFT 2014

Proof ofConcept

GEM DAQ Prototype System for LS1GEM DAQ Prototype System for LS1

P. Aspell

DAQ also with link to newCSC Trigger Mother Board

Gigabit Link Interface Boards


CURRENT R&D:CURRENT R&D:ZIGZAG STRIP READOUTZIGZAG STRIP READOUT


Previous Work @ BNLPrevious Work @ BNL

7/24/2012 HEP Division Seminar, ANL - Marcus Hohlmann

-100

-80

-60

-40

-20

0

20

40

60

80

100

3000 3500 4000 4500 5000 5500 6000 6500 7000

Reconstructed Position [µm]P

ositi

on E

rror

[µm

]

Zigzag strips:

• Charge sharing among adjacent strips allows quite sensitive position-interpolation in x-direction

• We are sacrificing the measurement of the 2nd coord. (y) to gain precision in the 1st coord. (x)

• CMS GE x/1 detectors are currently intended for 1D-coordinate measurements, so the zigzag approach is applicable to these detectors

x (measured coordinate)

Previous exp. studies show <100 µm resolution with 2 mm strip pitch is possible:

y

15

Concept:

ava-lanche

BNL


Zigzag strips vs. straight stripsZigzag strips vs. straight strips

Can reduce # of readout channels(and electronics cost) by 70% of current design

Improve resolution by factor 3-4

Pitch [mm]

Typical Resolution [µm]

Zigzag strips & analog r/o 2.0 80Straight strips & VFAT(current design, short end)

0.6 300

Improvement factor w/ zigzag strips

3.33 3.75

A “figure of merit”: 3.33 × 3.75 = 12.5

~ Potential for order of magnitude improvement over current design

Well worth a try!

&


R&D: Zigzag strips to reduce readout channel R&D: Zigzag strips to reduce readout channel count while maintaining high spatial resolutioncount while maintaining high spatial resolution


CA

D D

esign by C. P

ancake, Stony B

rook2 mm 2 mm

55Fe spectrum

Stand. CERN10cm × 10cmTriple-GEM

Gasgain

@ FIT

2012 CMS/RD51 beam test @ SPS2012 CMS/RD51 beam test @ SPS

M. Staib (FIT)

Zigzag Resolution = /2 = 73 µm

looking for hit in 5mm window centered on track

150 GeV/c µ & beams

June 2012

preliminarypreliminary

M. Staib (Fl. Tech)


Next steps for zigzag r/oNext steps for zigzag r/o• Develop successively larger zigzag strip

readout boards: – 30cm × 30cm (Detector already assembled)– 100cm × 45cm CMS GE1/1– GE2/1 prototype? (1.5-2m long)

• Test performance – Spatial resolution in magnetic field– Timing resolution achievable with analog readout


THE “BIGGER PICTURE”THE “BIGGER PICTURE”Some thoughts on…


Problem:• Experiments to face high

rates at LHC (HERA-B)

• Aging encountered in

original Micro-Strip Gas Counters (MSGC’s)

• MPGDs show sizable spark rates

Solution:→ First MPGDs invented: high readout granularities with microstrips and small pads lowering occupancies

→ Move avalanches away from materials (microstrips) towards empty space (hole): Gas Electron Multiplier

→ Distribute gain over several elements: Double-GEMs, Triple-GEMs


GEM Evolution: Problems & Solution GEM Evolution: Problems & Solution

Problem:• GEM detector size limited

to ~ 40cm × 40cm by alignment of two masks during production

• Detector construction using external stretching of GEM foils and epoxy glue (curing time) slows down assembly

• Spacers eat into GEM detector acceptance

• Rising demand for foils

Solution:→ Develop single-mask production process; allows large-area GEMs (currently up to 1m)→ Devise “self-stretching sans spacer” assembly technique (CMS GEMs)

→ Ditto…

→ Upgrade CERN workshop


GEM Evolution: Problems & SolutionGEM Evolution: Problems & Solution

NB: ALL solutions so far have basically come from CERN; US by far not a leader!

Problem:• Large-area GEM detectors,

e.g. in muon systems, require large number of electronics channels and big DAQ systems rising cost

• One dimension of chambers limited by width of Cu-Kapton foil base material (~60cm)

• Industrial foil production notoriously problematic (Tech Etch, New Flex)

(Future) Solution:→ Scalable Readout System→ Zigzag strips?→ Frontend electronics with much higher chan. integration (à la KPiX); could we do, say, 4k ch. on a single chip!?→ Work directly with industry? Involve NL’s?

→ Ditto; joint ventures between industry & HEP beyond SBIRs?


GEM Evolution: Problems & SolutionGEM Evolution: Problems & Solution

Brainstorming for “2020”Brainstorming for “2020”• In a phone meeting, someone asked the important question “Can MPGDs

complement silicon as vertex/tracking detectors in highest-rate environments to save cost?” Electron-Ion Collider detector designs in NP

• Can we automate chamber assembly (use robotics)? Cheaply mass-produce a “standard” large-area GEM detector (akin to the CERN standard 10cm × 10cm GEM detectors used for R&D)?

• Can we marry commercial flexible foil circuits and GEM foil technology? Put cheap surface mount readout electronics directly on r/o strip foil or on a GEM foil? => Save chip bonding, connectors, cables, i.e. cost. (see also Julia Thom’s talk on novel technology in EF sessions)

• Can we make MPGDs much more attractive to commercial applications (medical imaging, homeland security,...) so we can get cheap industrial mass production going?


Thank you for your time!Thank you for your time!


Argonne National Laboratory - Jan 11, 2013

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