The Compact Muon Solenoid Detector - Indico€¦ · Barrel wheels: Drift Tubes (DT) Endcap Disks: Cathode Strip Chambers (CSC) Return iron Yoke in red Resistive Plate Chambers (RPC)

TheCompact Muon Solenoid

Detector

Zoltán Szillási, Noémi Béni

CMS collaboration

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CMS detector overview

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The CMS Solenoid

CMS is built around a superconducting solenoid generating a magnetic field of 4 Tesla

The current necessary for this – 20 kA...

Superconducting NbTi wire cooled to ~4K

13m length, 6m inner diameter – enough to fit the tracker and calorimeters inside

(cost ~80 MCHF)

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Magnets in particle detectors

ATLAS A Toroidal LHC Apparatus

µ

CMS Compact Muon Solenoid

µ

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Two ways to detect a particle (in CMS)

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See the track

Or

Catch

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Tracking detector

Or

Calorimeter

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Particle identification in CMS

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The Inner Tracker

Measures the trajectories of charged particles

momentum = 1/curvature

The biggest silicon detector in history, over 220m2 of silicon

Inner part – 4 layers of pixeldetectors, outer part 10-11 layers of silicon microstrips

141 milions of read-out channels

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Event „pile-up”

In the LHC, several proton-proton collisions can occur in a single bunchcrossing (The image shows an event with 29 reconstructed vertices)

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Electromagnetic CalorimeterElectron and photon energy measurement~75 000 PbWO4 crystalsHomogeneous detector -crystals act as both the absorber and the scintillatorVery good energy resolution

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Hadron Calorimeter

Jet energy measurementBrass absorber interleavedwith scintillator layers (1)Steel blocks with embedded quartz fibers in the „forward” part (2)

(1)

(2)

CMS Muon System

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Z

Y

X

Global System of Coordinates

Barrel wheels: Drift Tubes (DT)

Endcap Disks: Cathode Strip Chambers (CSC)

Return iron Yoke in red

Resistive Plate Chambers (RPC) in both barrel and endcap

Yoke Endcap: YE

Yoke Barrel: YB

Barrel: 4 DT stations in 5 iron wheels and 12 (3) or 14 (1) phi-sectors: 250 chambers

2 Endcaps: 4 CSC stations mounted on 3 iron disksand 18 (3) or 36 (5) phi-sectors: 468 chambers

Muon Barrel (MB) stations

Muon Endcap(ME) stations

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The Muon System – Drift Tubes

Muon trajectory measurement (barrel)Measured quantity – drift time of electrons produced by the passing muonKnown drift velocity → distancemeasurement (~50-200mm precision)Alignment is very important

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The Muon System – CSC

Cathode Strip Chamber (CSC) measure muontrajectories in the endcaps

The chambers contain an array of positivelycharged wires, strung like a harp, over strips thatrun perpendicular to them.

The movement of electrons to wires and inducedcharge on the strips give two orthogonal positionco-ordinates

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The Muon System – RPC

Resistive Plate Chambers (RPC) Present in boththe barrel section and the endcaps

Two gas chambers each made of twooppositely-charged Bakelite electrodes, with a copper strip between the chambers.

Excellent time-resolution helps identify the collision that produced the observed muons.

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Trigger

The H → gg channel

One of these plots contains the (simulated) Higgs boson signal.

Can you spot it?

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Can you spot it?

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Can you spot it?

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Can you spot it?

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Can you spot it?

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Can you spot it?

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Can you spot it?

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Luminosity provided by HL-LHC opens new doorways to physics

D. Barney (CERN)26

HL-LHC: levelled L = 5x1034cm-2s-1 and pileup 140, with potential for 50% higher L & pileup

Physics reach will include SM & Higgs, with searches for BSM including reactions initiated by Vector Boson Fusion (VBF) and including highly-boosted objects Narrow (t) jets or merged (hadronic decays of W, Z) jets Ideally want to trigger on these narrow VBF & merged jets

Good jet identification and measurement: crucial for HL-LHC

Future detector upgradesTracker

Outer tracker:strip+strip (SS) and strip+macro-pixel(PS) double modules: 42M strips (192 m2) and 170M macro-pixels (25m2).

Inner tracker:1×2 and 2×2 modules: 2M hybrid pixels

(4.9 m2). 6× smaller pixel size than Phase-1.65 nm CMOS readout.

PHASE-2 TRACKER

[email protected] for CMS KICK-OFF MEETING -R&D ON EXPERIMENTAL TECHNOLOGIES -NOVEMBER 2017

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1×2 and 2×2 modules

25×100 or 50×50 µm2

PHASE-2 TRACKER


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1×2 and 2×2 modules

25×100 or 50×50 µm2Current tracker Future tracker

Future detector upgradesGas Electron Multiplier (GEM) in the endcap region

Installation during LS2:

GE1/1: ~50 m2, two-layer triple-GEM

Installation during between LS2 and LS3:

GE2: ~100 m2, two-layer triple-GEM.

RE3, RE4: ~90 m2, single-layer iRPC.

Installation during LS3:

ME0: ~60 m2, six-layer triple-GEM.

BEYOND 2030 –MUON SYSTEM

>20-year-old systems by 2030:

DT, RPC, CSC installed 2003-08.

CF4 (DT, CSC) and Freon (RPC).

Total surface ~10’000 m2.

Foreseen detector upgrades:

GE1 to be installed in LS2.

Followed by GE2 (2022) and ME0 (LS3).

Mature technology.

Production across centers worldwide.

Improved RPC in 2022-23.

Improve robustness and acceptance in cracks.

1.4 mm thinner gap and electrodes, r-measurement through readout at both strip-ends.

GEMs could step in for LS4 replacements, if needed.


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Gas Electron Multiplier (GEM) detectors are compact, gaseous particle detectors which were invented by Fabio Sauli at CERN in 1997, and were first introduced into CMS in early 2017.

Triple-GEMs consist of the following basic layers:• A drift cathode• Three GEM foils, sealed in a gas-tight

volume• Usually 70% Ar, 30% CO2

• A printed readout circuit board (PCB)• An electronics board (if necessary)• Plus a cooling circuit, aluminum cover, etc…

A GEM foil is a 50 μm-thick sheet of polyimide, coated with 5μm of copper on each sideand chemically etched with 50-70 μm-thick tapered holes at a pitch of ~140 μm (1). When put to a high voltage, the conducting copper and non-conducting polyimide of the GEM foils results in electric fields through the holes (2).

When a muon enters the chamber, it ionizes the gas. The ionized electrons drift towards the foils, where they encounter the electric fields. Here they multiply, drift to the next layer, multiply again, etc. until they are read out at the readout PCB as signal. This is known as an electron avalanche (3).

(1)

(2)

(3)

Triple Gas Electron Multiplier Detectors

Elisabeth Rose Starling

The GE1/1 system has the following main goals:

• Add redundancy in a high rate / background environment • Improve tracking• Allow for the measurement of the bending angle at trigger level

• This decreases the number of mismeasured muons by lowering the trigger threshold of soft muons

Triple GEMs in CMS – the GE1/1 Project

When CMS was first designed, it envisioned a system of forward resistive plate chambers (RPCs) in the muon endcaps. This was never realized due to worries about RPCs’ ability to handle background particle rates on the order of 10kHz. Instead, we are now adding 144 triple-GEM detectors (as 72 superchambers (1)) in this available space (2), called the GE1/1 system (3).

In 2017-2018, 5 superchambers were installed into CMS as a demonstrator system called the Slice Test (4).

Installation of thefull GE1/1 systembegan in July 2019(5) and will befinished by the endof Long Shutdown 2in December 2020.

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(3)

(2)

(4)

(5)

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Future detector upgradesnew endcap high granularity calorimeter (HGCAL)

3Maral Alyari

CMS High Granularity Calorimeter

• CMS electromagnetic and hadronic endcaps need to be replaced

• CMS will be going through major upgrades!

HGCal

HGCal is a 5-D imaging calorimeter (energy, x, y, z, t)

Concept: Remove complete endcapcalorimeter system and replace with HGCAL

Overall mechanical design of HGCAL heavily constrained by present endcap calorimeters

D. Barney (CERN)32

Present CMS endcap calorimeters HGCAL design

Concept: remove complete endcap calo. system and replace with HGCAL

Future detector upgradesnew endcap high granularity calorimeter (HGCAL)

Active Elements:

• Hexagonal modules based on Si sensorsin CE-E and high-radiation regions of CE-H

• Scintillating tiles with SiPM readout inlow-radiation regions of CE-H

Key Parameters:

• Full system maintained at -30oC

• ~600m2 of silicon sensors

• ~500m2 of scintillators

• 6M Si channels, 0.5 or 1.1 cm2 cell size

• ~27000 Si modules

~2m

~2.3

m

Electromagnetic calorimeter (CE-E): Si, Cu/CuW/Pb absorbers, 28 layers, 26 X0 & ~1.7lHadronic calorimeter (CE-H): Si & scintillator, steel absorbers, 24 layers, ~9.0l

Silicon modules

D. Barney (CERN)34

Baseplate

Kapton

Silicon

PCB 7 hexagonal modules for 2017 beam test

Silicon sensor glued to baseplate and PCB containing front-end electronics

HGCAL will include 27000 modules based on hexagonal silicon sensors with 0.5-1cm2 cells

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Once more:

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A proton-proton collisionas seen by CMS

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The End

This talk was based on the slides made by Piotr TraczykCheck his cool video about Higgs Boson Sonification

https://www.youtube.com/watch?v=SXEnDM3hydM

Credits

Many thanks to:

Piotr Traczyk

Andre David Tinoco Mendes

David Barney

Maral Alyari


…. and the full CMS collaboration for the excellent work

More information about CMS: http://cms.cern.ch

Documents

The Compact Muon Solenoid Detector - Indico€¦ · Barrel wheels: Drift Tubes (DT) Endcap Disks: Cathode Strip Chambers (CSC) Return iron Yoke in red Resistive Plate Chambers (RPC)