Instrumentation Frontier Community Meeting – Snowmass Process 2013

GEM Upgrade for CMS Forward Muon System

Marcus Hohlmann

(an IF-EF liaison for gaseous detectors)

Florida Institute of Technology

Argonne National Laboratory - Jan 11, 2013

MOTIVATION & INTRODUCTION

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

Premise 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 C

M

S. Use Phase I to evaluate muon technology for Phase II.

• The

high η

muon region in particular will need

and triggering robust and redundant tracking

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

GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL 1/11/2013 3

CMS G

EM

E

ndcap Chambers

The 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

operation at the LHC and its future upgrades into Phase II: and be suitable for

GEM Detectors GE3/1 GE4/1 GE1/1 simulation geometry

GE1/1

in nose of first Endcap Yoke

CMS Detector

1/11/2013 GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL 4

Four superchambers in their final position on endcap yoke

Integration into CMS

Installation sequence: Superchamber (Two Triple-GEMs)

A. Conde Garcia 1/11/2013 Mounting on yoke disk GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL 5

Expected Benefits for Reconstruction & Trigger

Expected gains in momentum resolution at high-p T Staving off looming muon trigger inefficiencies at high-

 Simulation for one GEM station

Expected CSC inefficiency

at

PU=400

due to Cathode LCT - Anode LCT timing mismatching A. Safonov (Texas A&M)

Acceptance impact:



distribution of 4 muons in H → ZZ → 4µ 1.6<



<2.4

M. Maggi (Bari) – GEM Workshop 3 Strip Readout granularity: # GEM strips / # RPC strips (orig. TDR) 1/11/2013 Paolo Giacomelli (Bologna) & Markus Klute (MIT) – GEM Workshop 3 GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL 6

CONSTRUCTION OF FULL-SIZE GEM PROTOTYPES

1/11/2013 GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL 7

Evolution - GEM foil stretching

Readout PCB

Current state-of-the-art: Self-stretching assembly sans spacers (CERN)

GEMs Drift electrode Detector base pcb Tightening the horizontal screws tensions the GEMs & seals gas volume only glue joint in assembly

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

2012

R. De Oliveira, CMS-GEM/RD51Workshops CERN & U. Gent 1/11/2013 GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL 8

3 rd GE1/1 Prototype: “Self-Stretched - Sans Spacer” No spacers in active volume GEM foil in inner frame assembly

GEM foil with inner & outer frame GEM tensioning

Vias for strips sealed w/ kapton

compact HV divider 

-sector with 384 radial readout strips (12.4 cm long)

HV noise filters

Inside of readout board with O-ring seal

1/11/2013 Chamber closed by readout board with Panasonic connectors for frontend electronics GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL

CERN 2012

9

Full-size GE1/1 Detector Prototypes

  

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/CO 2 ( 70:30 ; 90:10)



Ar/CO 2 /CF 4 ( 45:15:40 ; 60:20:20)



Gas flow ≈ 5 l/h

1/11/2013

New self-stretching technique has been applied to the full-size CMS GE1/1 GEMs 4 prototypes produced & tested at CERN in 2012 1 prototype to be assembled & tested at Fl. Tech in early 2013 5-8 new final prototypes to be produced for installation of 4 during first LHC long shutdown (LS1)

GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL 10

Next: No Gluing & PEEK frame

Panasonic readout connector Outer frame Use O-ring to seal outer frames to drift plane; removes ALL glue joints On-foil protection resistors Readout PCB GEM foils Now PEEK Inner frame Drift Board 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

1/11/2013

Rui De Oliveira

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

LHC Long Shutdown 1

P5 CAVERN UXC

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

GE2/1 ME2/1

Objective: Participate in CRAFT 2014

ME1/1

GE1/1 GE1/1

ME1/1 YOKE CMS

Proof of Concept 4 GE1/1 GEM chambers in LS1

• •

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. 1/11/2013 GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL 12

GEM DAQ Prototype System for LS1

DAQ also with link to new CSC Trigger Mother Board

1/11/2013

Gigabit Link Interface Boards

GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL

P. Aspell

13

CURRENT R&D: ZIGZAG STRIP READOUT

1/11/2013 GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL 14

Previous Work @ BNL

Zigzag strips:

Previous exp. studies show <100 µm resolution with

2 mm

strip pitch is possible: y 100 80 60 40 20 0 ava lanche 3500 4000 4500 5000 5500 6000 6500 7000 -40 -60 -80 -100 BNL

Reconstructed Position [µm]

x (measured coordinate)

Concept:

• Charge sharing among adjacent strips allows quite sensitive

position

-

interpolation

in x-direction • We are sacrificing the measurement of the 2 nd coord. (y) to gain precision in the 1 st coord. (x) • CMS GE x/1 detectors are currently intended for

1D-coordinate

approach is applicable to these detectors measurements, so the zigzag

Zigzag strips vs. straight strips

Zigzag strips & analog r/o Straight strips & VFAT (current design, short end) Improvement factor w/ zigzag strips Pitch [mm] 2.0

0.6

3.33

Typical Resolution [µm] 80 300 3.75

1/11/2013 Can reduce # of readout channels (and electronics cost)

by 70%

of current design

&

Improve resolution by factor 3-4

A

“

figure of merit

”

: 3.33

×

3.75 = 12.5

~ Potential for order of magnitude improvement over current design



Well worth a try!

GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL 16

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

@ FIT

55 Fe spectrum

Stand. CERN 10cm × 10cm Triple-GEM

Gas gain

1/11/2013 2 mm 2 mm GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL 17

2012 CMS/RD51 beam test @ SPS

Zigzag Resolution =



/



2 = 73 µm 150 GeV/c µ &



beams

1/11/2013 M. Staib (FIT)

June 2012

looking for hit in 5mm window centered on track M. Staib (Fl. Tech) GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL 18

Next 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

1/11/2013 GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL 19

Some thoughts on…

THE “BIGGER PICTURE”

1/11/2013 GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL 20

GEM Evolution: Problems & Solution

•

Problem:

• Experiments to face

high rates

at LHC (HERA-B)

Aging spark

encountered in original Micro-Strip Gas Counters (MSGC’s) • MPGDs show sizable 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 1/11/2013 GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL 21

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 1/11/2013

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

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

GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL 22

GEM Evolution: Problems & Solution

Problem: (Future) Solution:

• Large-area GEM 1/11/2013 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) → 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 Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL 23

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?

1/11/2013 GEM Upgrade for CMS Forward Muon System - M. Hohlmann, Snowmass IF meeting, ANL 24

Thank you for your time!

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