Approved Plots from CMS Cosmic Runs (mostly CRUZET, some earlier)

13-October-2008

Cosmic Results 2

MTCC

2

HCAL

Magnet

Tracker

Muon chambers

barrel & endcap

ECAL

Summer/Autumn 2006

Goals:

Test a “vertical slice” of all aspects of final CMS on the surface

Commission the CMS magnet

Measure the magnet field map

Magnet Test and Cosmic Challenge

Cosmic Results 3

Golden MTCC event

Run 2605 / Event 3981 / B=3.8 T / 27.08.06, 22hMuon traversing DT, RPC, HCAL, ECAL, Tracker

HCAL

HCAL

ECALTracker

Cosmic Results 4

Cosmic Muon Measurements

4

B=0 B=4T

Momentum Distribution (4T)

Behavior of detectors in the magnetic field was verified using MC and physical

observables

Cosmic muon charge ratio

measurement from MTCC

CMS NOTE-2008/016

Cosmic Results 5

Field map

• Measured during MTCC ‘06

• Finite element calculation of field in entire detector volume performed (at 2, 3, 3.5, 3.8, 4 T)

• Field map with 12-fold phi-symmetry provided for physics

• Analysis of field mapper data: – Calibration corrections of order 10-4 in gain and

offset derived, to produce field model that agrees better than 5*10-5 with measurements and with Gauss' law in tracker volume (note: original calibration ~5*10-4 !) [PhD thesis V.Maroussov, Purdue University, May 2008.]

∆

B = 0...

3.8T map

Z (m) R (m)

δBz

(T)

Cosmic Results 6

First cosmic muon

triggers underground

Upgrade to final DAQ software architecture

First coincidence of 2 subsystems

Reached scale of ’06 Magnet Test &

Cosmic ChallengeFinal DAQ hardware,

final services

Muon Tracks in Si-Strip Tracker

Subdetector and trigger considered separately - 19 items, each equally weighted - box size represents approx. fraction included (25%, 50%, 75%, 100%)

With exception of some parts of RPC, all CMS detector and trigger system ready for LHC

% C

MS

ALL CMS with exception of ½ RPCE

Start of full week exercises

(CRUZET 1)

Global Runs

Cosmic Results 7

Fraction of CMS Systems in Global Runs

Fraction of Live Front Ends in CMS Global Runs

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Fra

ctio

n

HCAL

ECAL

DT

CSC

RPC

StripTrackerPixelTracker

Mu

on

Cabling complete, final power & cooling

become available

Cooling ready for Strip Tracker

Pixel system and ECAL endcaps

installed

Cosmic Results 8

“Integrated (cosmics) luminosity”Events collected by CMS in global runs during 2008

Cruzet3

Cruzet4

Cruzet2

Cruzet1

September 10

DAYS after March 31, 2008

Cosmic Results 9

DT Cosmic Muon Movie

Cosmic Results 10

CRUZET: Cosmic Muon Coincidence

ECAL

HCAL

DT and RPC

Cosmic Results 11

CRUZET: showering muon

Energy: ~290 GeV

Cosmic Results 12

z (a

t su

rfac

e) [

cm]

x (at surface) [cm]

Tag & Probe with cosmics

“X-ray” image of the shaft using cosmic rays

linea

r sc

ale

Probability to find at least one segment at the probe side

[deg]

TOF-compensated cosmic trigger: di-muon-like signal in DT

Probe muon trigger and reconstruction

12

Cable chimney

Soft muons

absorbed

TOPBOTTOM Cosmic rays extrapolated to the

surface (80m)

Cosmic Results 13

CRUZET ECAL Barrel Occupancy– Cosmic signal is reconstructed as cluster in 5x5 region

with seed crystal(s) above a threshold (~100 MeV)• 2M events selected from 13.6M logged events (15% of muon triggers)• 61K crystals, O(100) events/crystal in top-bottom regions

TOP BOTTOM

EB

+E

B-

Supermodules intentionally left susceptible to noise for diagnosis

HV problem caught by prompt analysis team

Masked trigger tower

Cosmic Results 14

in detector units

in

det

ect

or

units

Reconstructed clusters matching muon tracks

(DT triggered events)

ECAL

e/ trigger tested by triggering on m.i.p. signal

synchronized to muon & HCAL triggers

Trigger acceptance

Trigger acceptance

Track-cluster association

trigger: 290 GeV cluster!

14I. Mikulec

3x3 energy deposit for cosmic muons – confirms absolute energy scale to few %

GeV/cm

Cosmic Results 15

CRUZET3 Global Tracks: Tracker + Drift Tubes

Prerequisites:

infrastructure, -trigger, DAQ integration,

r/o synchronization,

muon calibration, reconstruction/tracking, etc. ...

Global Run Jul08 Tracker

ECAL

HCAL

Muon System

Tracker

15

Cosmic Results 16

CRUZET3: Global Tracks

Tracker

ECAL

HCAL

Muon System Di-muon Trigger:

• Drift-Tube coinc. in top+bottom, each 2 station segments

Muon signals traced through• muon system• Tracker TOB+TIB• ECAL• HCAL

Global track fit

Data being used for alignment

16

Cosmic Results 17

CRUZET4: Endcap ECAL

Cosmic Results 18

CRUZET4: ECAL Endcap

Cosmic Results 19

CRUZET4: Endcap ECAL

19

DT

Endcap ECAL

Barrel ECAL

HCAL

Cosmic Results 20

Tracker/Pixel

20

Aug08: all parts of Tracker integratedFirst cosmic tracks with Pixels

Pixel

Cosmic Results 21

Testing the muon High-Level Trigger

• Routinely running High-Level-Trigger menu (+ dedicated cosmic muon trigger path)

• Global fit with “L3” tracker track, seeded from “L2” muon track, seeded from “L1” trigger candidate:

Run 58733, event 1741135

0T

Cosmic Results 22

Standard MuonID sequence (Cruzet III)

• Part of the standard muon ID

• 90k events with tracker track (B off)

• Tracker tracks are extrapolated outward and matched to

– Muon segments

– Calorimeter deposits

0T

Calorimeter only!

Muon compatibility

No. of matched segments

Δx between track extrapolation and muon segment in station 1 (cm)

Cosmic Results 23

Cosmic Shower Events:

• 0.02% rate of events with >100 segments in ~10M cosmic events at 0T

• Event-by-event spread in phi compatible with multiple scattering → all events compatible with ~parallel muon shower

Cosmic Results 24

Muon multiplicity

Analyzed events spanning 5 orders of magnitude in muon multiplicity !

illustrates versatility and robustness of detector and software

Run 50908event 1057286541 segments

Cosmic / Beam Halo O(1) muon

Cosmic ShowerO(10-100) muons

Beam “splash” eventO(105) muons

Analysis using: tracks ... segments ... hits cosmic charge ratio shower origin shower energy and shape

... ... ...

Cosmic Results 25

8.1 GeV

25

3.1 GeV

Dedicated muon reconstruction

• Navigation + seeding optimized for cosmic and beam halo muons

– not pointing at IP, traversing whole CMS– using default propagator + Kalman Filter fit, updated to

work both with B on and off

6.2 GeV

12.6GeV

38.1GeV3T

CMS Note -2008/001

Cosmic Results 26

Cosmic-Muon Momentum Spectra

• Measuring the momentum:

– Using centrally RECOed data from run 60302:

Muon system Only Tracker only

Momentum (GeV/c) Momentum (GeV/c)

Short run at 3T