LHCの最新の状況と実験予定
7. Sep. 2009
ミニ研究会： LHCでの余剰次元研究
T. Kobayashi

LHC Cooldown Status
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LMC (w35) schedule (from M.L)2

Excerpt from the message sent by to the CERN users DG on 6/8/2009
Press Release (06.08.2009)
The LHC will run for the first part of the 2009-2010 run at 3.5 TeV per beam, with theenergy rising later in the run.
That's the conclusion that we've just arrived at in a meeting involving the experiments,
the machine people and the CERN management.
We've selected 3.5 TeV because it allows the LHC operators to gain experience of runningthe machine safely while opening up a new discovery region for the experiments.
………………………………….
The procedure for the 2009 start-up will be to inject and capture beams in each direction,
take collision data for a few shifts at the injection energy, and then commission the ramp
to higher energy. The first high-energy data should be collected a few weeks after the
first beam of 2009 is injected.
The LHC will run at 3.5 TeV per beam until a significant data sample has been collected andthe operations team has gained experience in running the machine. Thereafter, with thebenefit of that experience, we'll take the energy up towards 5 TeV per beam.
At the end of 2010, we'll run the LHC with lead-ions for the first time.
After that, the LHC will shut down and we'll get to work on moving the machine towards
7 TeV per beam.
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LHC Schedule 20094

・2010:• 1 month pilot & commissioning• 3 month 3.5 TeV• 1 month step-up• 5 month 4 - 5 TeV• 1 month ions56

Detector present status (after Winter 2008-2009 shut-down)
Sub-detector

Number of channels

Operational fraction (%)

Pixels80 M

98.5

SCT Silicon Strips

6M

99.5

TRT Transition Radiation Tracker

350 k

98.2

LAr EM Calorimeter

170 k

99.1

Tile Calorimeter

9800

99.5

Hadronic endcap LAr calo

5600

99.9

Forward LAr calorimeter

3500

100

MDT Muon Drift Tubes

350 k

99.3

CSC Cathode Strip Chambers

31 k

98.4

RPC Barrel Muon Trigger

370 k~95.5 ( aim >98.5)

TGC Endcap Muon Trigger

320 k

99.8

Concerns are long-term reliability of some components:
Low-voltage power supplies of Liquid-Argon and Tile calorimeters;
Liquid-Argon readout optical links;
Inner detector cooling.
Back-up solutions being prepared for installation in future shut-down.
7Expected ATLAS performance on “Day-1”(examples based on test-beam, simulation, and cosmics results)

ECAL uniformity
e/γ E-scale
Jet E-scale
ID alignment
Muon alignment

Initial Day-1

Ultimate goal

Physics samples to improve(examples)

~2.5%
2-3%
5-10%
20-200 μm
40-1000 μm

0.7%
<0.1%
1%
5 μm
30 μm

Isolated electrons, Z→ee
J/ψ, Z → ee, E/p for electronsγ/Z + 1j, W → jj in tt events
Generic tracks, isolated μ, Z → μμ
Straight μ, Z → μμ

Overalluniformity

ECAL uniformity:• local uniformity by
construction/test: 0.5%
• residual long-range non-uniformities(upstream material, etc.):~ few percent
Æ use Z-mass constraint to correct~ 105 Z → ee events enough toachieve the goal response
uniformity of ~ 0.7%
K.Jon-And, Lepton Photon, Hamburg, 17/8/2009

ATLAS preliminary

0.7%

Number of Z → ee events

88Conclusions• The ATLAS experiment is in excellent shape• The fraction of non-working channels is on the per mille level• Analysis of ~600 M cosmics events, as well as single beamdata in Sept 2008, shows better detector performance thanexpected at this stage• Software and computing have proven to be able to cope withsimulation, analysis and world-wide distribution of massive
amounts of data

• After 20 years of efforts building all aspects of the experiment:
ATLAS is eagerly waiting for LHC collisions data …
K.Jon-And, Lepton Photon, Hamburg, 17/8/2009

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Conclusions
 During the autumn 2008 LHC beam & cosmics run, the sub-detectors, online,offline, computing and analysis systems all performed well.
 The ensuing shutdown included broad maintenance activities and a
programme of carefully selected repairs interleaved with installation of thepreshower detector.
 Much VERY useful information has been extracted from the CRAFT08 data.
Plan to publish ~25 papers by end-Sept.
The software, computing systems and analysis systems are being exercisedin CRAFT09 and by generating, (and soon) distributing and analysing 200M
events to update 10 TeV “physics analyses” (and soon 7 TeV) using s/w
release intended for data taking.
The experiment is now closed and is being used for a long magnet-on
cosmics run to put it into “beam-ready” state.
 CMS will (again) be ready, and eager, for LHC beam.
R. Cousins LP09 Aug 091010

Bottles of champagne to be offered by ATLAS
to the LHC accelerator teamFirst one delivered …

K.Jon-And, Lepton Photon, Hamburg, 17/8/2009

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Backup Slides12Large Hadron Collider (LHC) at CERN・ 14 TeV の陽子・陽子衝突型加速器
・ LEPトンネルを利用
・ 建設に14年
・ 総建設費は約5000億円
・ 2008年9月10日first beam周回に成功* CERNのLEP(e+e-）は 200 GeV* 米国フェルミ研究所のTevatron(pp)は 2 TeV

2-in-1超伝導ダイポールマグネット：
磁場強度 8.3T、超流動ヘリウム温度 1.9K、長さ 14.3m、1232台

13Splash events on Sep.10, 2008
(LHC first beam circulation)

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LHC Incident (19 Sept. 2008)
１．Sector34のパワーテスト中、dipoleとQ-magnetの超伝導ケーブルバス結線部の抵抗値が増加→ 温度上昇 → クエンチ → クエンチ保護回路作動
２．電源トリップが作動したものの、アーク放電が発生→ 真空（断熱）容器に穴
３．真空容器内およびビームパイプ内にヘリウムが流出→ shock wave
４．減圧排気バルブが開放されたが、→ 真空隔壁が破壊、いくつかのマグネットが動かされ→ 6トンのヘリウムがトンネル内に流出（15t/sector）

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http://lhc.web.cern.ch/lhc/

4 sectors warmed up

対策
・53台のマグネット（39 diploles +14 quadrupoles）
を地上に持ち出して修理・チェック・クエンチ検出、異常な電圧や熱の検出システムの改善
・安全開放バルブの容量と数を増強
・ビームパイプの掃除・真空隔壁を備えたQ-magnetのサポートを強化

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MagnetSplice Resistance
Measurements

copper bus bar 280 mm2

current

Magnetcopper bus bar 280 mm2

superconducting cableinterconnection (soldered)

We must be sure that the joint between the sc cables
is good. Measurements of nano-Ohms at 1.9K
We must be ensure that the copper stabiliser is continuous.
Measurements of micro-Ohms at warm
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General purpose detectors
for pp collisions
ATLAS

Length : ~45 m
Diameter : ~24 m
Weight : ~ 7,000 tons
Electronic channels : ~ 108
Solenoid : 2 T
Air-core toroids+ LHCb, ALICE, TOTEM, LHCf

CMS

Length : ~22 m
Diameter : ~14 m
Weight : ~ 12,500 tons
Solenoid : 4 T
Fe yokeCompact and modular
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ATLAS

CMSTRACKER

Si pixels + strips
TRT → particle identification
σ/pT ~ 4x10-4 pT ⊕ 0.01

Si pixels + strips
No particle identification
σ/pT ~ 1.5x10-4 pT ⊕ 0.005

EM CALO

Pb-liquid argon
σ/E ~ 10%/√E uniform
longitudinal segmentation

PbWO4 crystals
σ/E ~ 2-5%/√Eno longitudinal segmentation

HAD CALO

Fe-scint. + Cu-liquid argon (≥ 10 λ)σ/E ~ 50%/√E ⊕ 0.03

Brass-scint. (≥ 5.8 λ + catcher)σ/E ~ 100%/√E ⊕ 0.05

MDT, CSC, RPC, TGC
σ/pT ~ 7 % at 1 TeV
standalone

DT, CSC, RPC
σ/pT ~ 5% at 1 TeV
combining with tracker

MUON

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Peak Luminosity(2008年夏の時点での予想）

Int. Luminosity(fb-1)

New
injectors +IR
upgradephase 2

Design lumi.
(1034 /cm2/s)

Collimation
phase 2

Linac4 +IR
upgradephase 1

2011年： 14TeVでO(1) fb-1 (?)
2012年： O(10) fb-1 (?)(R.Aymar, Plenary ECFA)
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