1994 US CMS 273 members 37 institutes
DOE contribution 200M cms 200M atlas 100m LHC
CMS Total 465.6 CHF ($372m) magnet 121.9 CHF (25%)
Atlas magnet (40%)
Me = 9.11e-31 Kg
Title Slide – starting next year you will see major discoveries in HEP
I am an experimentalist on CMS detector
First a quick look at the physics
And then a detailed look at the detectors which make this possible
Monte Carlo typical collision at 14 TeV
Slide 2 - quantum electrodynamics g-2 measured to 10 decimal places
GF 5 places
MZ, MW 5 places 0.1% in cross section
Alpha_s 4 decimal places
Fundamental theories don’t have 26 parameters
Why does nature repeat itself three times at different mass scales
Why do fundamental particles have mass
Slide 3 - intertwined in the standard model is the higgs particle
Theory doesn’t converge without it
W,Z get mass through interaction with Higgs Field
Beautiful mathematics idea from Solid State Physics 1965
Field Theory – spin 0 particle +Turn on new force (gauge interactions)
New objects with mass appear. Number of spin states increase.
Eats complex amplitude
Mechanism can explain fundamental particle masses
Slide 4 - Steal Wilczeks’ book title
Finally a way to get rid of fundamental mass
new view of fundamental particles
energy/mass is in the fields
Explain layman’s view
Very Pretty but where’s the higgs
Slide 5 – Higgs is not enough
Very difficult to have a low mass spin 0 object (distasteful)
Natural explaination comes from new symmetry SUSY
Slide 6 - LEP shutdown Nov 2000
Build new accelerator to find higgs
Remove all magnets put in 5000 new ones
Rebuild all experimental halls
Worlds largest accelerator
Talk about Atlas and CMS. Alice is designed for heavy ion. LHC B for b physics
Magnets have reached CMS detector
Slide 7 – acclerator will provide 14 TeV cm energy
Proton complex objects 3 valence quarks + sea of qq pairs and gluons
Know probability of each type of constituent carrying a fraction of beam momentum
Glue-Glue dominates
Higgs Production modes
More important – decay modes
There are others but these are the cleanest
Slide 8 – These are international experiments. CMS as an example
More US than any other country
Your government put in 0.5 billion dollars
Three major subdetectors dominated by Americans
Slide 9 - Detectors are hugh. Basics physics as energy/momentum increases
bend decreases.
In a 4 T field a 300 GeV particle bends in 250m radius
Deviation from straight line is 2mm! Need to measure
To ~200um over these large detectors
Slide 10 –
The two major detectors on LHC to scale
Both share very similar subsystems
Major difference is choice of magnetic field
Atlas:
relatively small central solenoid (2t)
Calorimetry outside solenoid.
Precision muon measurement in large toroidal field (40% cost)
CMS: Eiffel tower 7300 tons
Large central solenoid (4t) (25% cost)
Calorimetry inside solenoid.
Muon system measurements in return yoke.
Slide 11 –
Photons no track + electromagnetic shower
Electrons track +electromagnetic shower
Hadron track+strong interation shower
Neutral hadron no track + electromagnetic show
Muon to heavy to brehmstralung photon passes thru anything
Slide 12 –
Schedule of CMS run by LHC Civil engineering
Atlas hall habitable for over 1.5 years
CMS hall ready for occupancy Oct 1, 2007
Atlas being in final resting place
CMS being build above ground. Need to cable starting now.
Slide 13 –
CMS build around world’s largest solenoid
4T central field
2.7 GigaJoules stored energy (load 747 going 400 mph)
Cool down successful
Reached B=4.003T 2 weeks ago
Test dumping of 2.7 Gigajoules. Superconducting coils go normal.
Helium changes phase. $10000 done three times
Exciting times at CERN.
Magnet ready.
Slide 14 -
Atlas build around toroids
4-8 Tm bending power
Cooled down. Testing measuring magnet field right now.
Will obviously be ready.
Slide 15 –
Give status of detector from interaction outward
CMS tracking in 4 T magnetic field.
Thousands of tracks to reconstruct.
80 million tracking elements (200x LEP detectors)
pixels near center (good virtex position resolution)
Slide 16 –
Silicon detectors in hand
Integration in device done.
Installation early next year.
In good shape. Pixels installed after Nov 08 pilot run.
Meantion radiation
Slide 17 –
Atlas system similar. Pixels, Silicon strips.
Straw tube (TRD) electron identification
Completely finished.
OSU atlas group designed and built chips for optical communications
(data path to outside)
Slide 18-
Monte carlo of muon momentum resolution for two detectors
CMS mult scattering in iron return yoke limits muon system
Resolution central detector (B=4T dominates)
Atlas resolution in Toroids Dominate.
CMS combined sightly better, Time will tell
Slide 19-
Inside magnet
CMS opted for crystals to measure e’s, and gamma’s
80,0000 crystals in system
Presample 3x rejection pi0/gamma
Slide 20 –
Crystals need to be grown, Russia, China
Barrel Complete April 2007
Famous plot within collaboration
Endcaps get crystals starting now.
Production schedule tight.
Won’t be ready for commissioning run (shown in red)
Ready for physics
Slide 21 -
Outside solenoid
Atlas uses liquid argon/Pb ECAL
CMS almost factor of 2 better resolution
Further consequences later
Slide 22 –
Inside solenoid
CMS endcap and barrel calorimeter stacked
Scintillator brass tiles, WLS fiber readout
15,000 channels (3 radial segmens)
Good position
Picture of being stacked
Coverage
Slide 23 –
Barrel to be inserted in magnet
Endcap known as the Nose
Both detectors and electronics done/operational
Swords to plowshares
Slide 24 –
Outside magnet
Barrel Fe-Scint, endcap Cu-argon
Installed/Working
Slide 25 –
Measured HCAL resolution
Atlas factor of 2 better
CMS crystals -> non compensating HCAL
Pay for good gamma, e resolution
Slide 26 –
CMS Muon System made of 2 major subsystems
Drift Chambers 200k channels 200um resolution
Complete Dec 6
Slide 27 –
CMS Endcap Muon CSC
Self advertisement, OSU build Cathode FE electronics,
Data Aquistion electronics (4 boards) 5/8 main electronics
Boards in system
Active area size of football field. With good resolution
90% installed and commissioned
Slide 28 – advertise
Slide 29 – advertise
Slide 30 – advertise
Slide 31- Atlas MDT cover most area. CSC most forward (rate)
Trigger chambers. Done by Summer 2006
Slide 32-
Atlas short. Slides given to me. Understanding of detector.
Toroids inspired us all with awe.
Impossible to do justice with pictures
Slide 33-
Favorite slide
Trigger systems quite complex both AtlasCMS
Reduce input by 7 orders of magnitude.
Rate off chamber matches www world bandwidth
First Level Trigger reduces this to 100kHz
Farm Reduces this to 100 Hz
Slide 34- Whole talk required for trigger, Most system present. Extra
Capability summer 07. Second level trigger is large farm.
First 600 PC’s just purchased and will be installed at
Point 5 december.
Slide 35-Even at 100Hz data storage is incredible. Unthinkable 5 years ago.
CMS Atlas each produce on order of 20TB/day
Castor easily writes to tape 5x this amount
Distribution: Tier 1 and 2 centers
30 TB/day, with delay ok
Slide 36 - All components on CMS and Atlas have undergone extensive
Tests. Every amplifier. Test beam. Radiation tests. Rate tests.
Continuity tests. One has to make them work together
Slide 37 - elephant hunters (gone)
Slide 38 - first closing took 4 days instead of 4 hours
Lookouts posted
Airpads to grease pads
Camera survey 50,000 pictures from different positions
Increadible accuracy for a chamber this size
Slide 39 - pins hit electronics for 3 chambers, landed between CFEBs.
No damage, incredible
Slide 40 - Beautiful cosmic ray events passing though all detectors. Large
Trigger rate 200 Hz. Analysing and fitting data as we speak.
Slide 41 - Atlas well toward being fully installed
CMS moves to new come. A lot to do.
In 8-9 months
Slide 42 - Lowering 10cm per side
Takes hours. All work stops as we watch webcams
Slide 43 – Movie
Slide 44 – Movie
Slide 45 - LHC schedule.
Delivery of magnets on schedual.
Impossible to fully commission all magnets for 7TeV running.
Will commission ¼ other ¾ in Nov to May break
Will run at 900 GeV CM
Three stages
Random bunches, 75 nsec bx interval, 25 nsec bx interval
1x29-2e33
Slide 46 - A commissioning run. Luminosity probably on the low side.
Few W’s and Z’s . Lots of min bias events with single muons
p>100 Gev.
We have lots to understand
Slide 47 - When LHC turns on, it is expected to have reasonable luminosity
Higgs at 200GeV, Susy at 1TeV 1st year
Super LHC installed 2013.
Slide 48 - Atlas and CMS will be ready for physics run May 2008