LHCb
description
Transcript of LHCb
LHCb
SAC Review MeetingApril 17, 2008Marcel Merk
for the LHCb group
Contents:• Velo and PileUp• Outer Tracker• Software
b-b in LHCb
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LHCb event rate: 40 MHz1 in 160 is a b-b event
• vertices and momenta (mass) reconstruction • effective particle identification (π, К, μ, е, γ)• triggers
qb qb
3
• Silicon strip detector• Reconstruct primary and
secondary vertices• Tracking, use R-Phi geometry• Pile-Up Trigger in L0
The VErtex LOcator in LHCb
Velo “Specials”: Detectors move to 8mm from beam Detectors inside vacuum Cooling with 2-phase CO2
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• Straw tube detector• Momentum determination with
TT and magnet• Tracking, use XUVX geometry• 3 OT stations: T1, T2, T3
The Outer Tracker in LHCb
View of LHCb in Cavern
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VELO
Muon det Calo’s RICH-2 MagnetOT RICH-1
VELO
Muon det Calo’s RICH-2 MagnetOT RICH-1
Installation of major structures is complete
VeLo Project
NIKHEF provides Velo deputy projectleader
Nikhef Contributions:• Mechanics + RF • Vacuum control • Motion control• CO2 cooling• Pile-Up trigger• Commissioning
Collab.: Heidelberg, MPI, Liverpool, Glasgow, CERN, Lausanne, Syracuse, VU, Nikhef
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The Detector Vacuum box (“RF Box”)
30 mm
Thin, leak-tight corrugated RF foil between sensors and beam
Superplastic pressing of 300 mm Al foil with hot gas
Welding into a vacuum tight box
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The Detector Vacuum box (“RF-box”)
Leak rate between beam and detector volumes determined to be : 3.2x10-5 mbar.l/s @ 1 mbar He No problem for normal operation, venting and evacuation Risk: saturation NEG coating during installation Replacement in 2009 R&D ongoing for improved production method
Dp < 5 mbar at all times!
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Half Velo-detector in assembly lab
Operation of both detector halves tested in assembly lab17-4-2008 9
Installation (Oct 2007)
CO2 cooling system
R507a chiller
2-phase
2-phase
cond
ense
r
evap
orat
or
60 m concentric tubepump
rest
rictio
n
accumulatorshielding wall
liquid liquid
VELOdetector
coolingplant
2-phase CO2 cooling system Low mass Radiation hard Redundant / backup system
Only passive components in radiation area Detector temperature (evaporator) is controlled by pressure in accumulator Isothermal because of liquid-vapor mixture
CO2 loop
-25 ‘C
-40 ‘C -25 ‘C
-25 ‘C
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Cooling Plant Installation (summer 2007)
CO2 Unit Freon Unit
Controls PLC
accumulators
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Velo Cooling tests under vacuum
T= -10oC
TRF-foil≈ +9oC
20oC
10oC
0oC
-10oC
-20oC
T (oC)
Time (hours)
Performs well
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Vacuum
During pumpdown and venting: Dp < 5 mbar between beam-vacuum and detector-vacuum17-4-2008
pdetector
pbeam
T= -10oC
10-8
10-5
10-2
P [mbar]
TRF-foil≈ +9oC
Effect of Cooling on Vacuum
Reach p < 10 -8: OK
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Time
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Velo Commissioning
Outlook Velo (May-June):Power up C-side modules under neonOperate C-side under vacuumRepeat for A-side detector halfThen look forward to beam…
Noise level OK
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All cables and connectors checked (20% LV modules missing)
Cooling, Vacuum and Motion being finalized Hardware interlocks tested
Basic ECS software available, continuously being improved
First R-f station been powered up and read out under bias voltage (80 V):
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• All detectors/cables/fibers connected– Datapath established (apart from Output Board)
• Final test of connections in May• Implementation in Trigger/DAQ to be worked on
– Test with Level-0 decision unit planned in June• PVSS work ongoing
Hybrids kaptoncables
repeaterboards
transitionboards
opticalboards
VEPROBboards
outputboard
L0DU@IP8
AnalogTell1
digitaltell1
Pile-Up detector2 dedicated R-stations provide: 1,2,n vertices for each bunch crossing luminosity per time interval
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Outer Tracker ProjectCollab.: Dortmund, Heidelberg, Warsaw, Cracow, Bejing, VU, Nikhef
NIKHEF provides OT project leader
Nikhef Contributions:• Production and Installation: mechanics & electronics• Infrastructure: frames and support bridge• Quality Assurance• Commissioning• Irradiation Studies
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1917-4-2008
Detector Installation - completed
LV,HV, ECS/TFC..
Cooling and Gas
Detector Modules
Alignment: Stations positioned with no x-y-z rotations to
+- 0.5 mm xyz of modules known to +- 0.5 mm Reproducibility of open-close ~ 30 mm (except
1 C-frame) Final x-alignment of C-frames using RASNIK
(RASNIK installation completes in April)
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OT Electronics . 80% detector is equipped and installed
80% -> 90% is ready for installation
90% -> 100% Produced and tested: May Installed: June
100% -> 110% Finished after summer
C-frame equipped with FE boxes
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OT Commissioning Testing individual channels with a source: 21 bad wires out of 32040 DAQ: OT has been succesfully included in global commissioning runs Cosmics: Cosmic tracks and showers have been observed…
Cosmic trigger in OT
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Ageing Phenomenon
o Gain loss “in the neighborhood” of the irradiation point:
Croissant? Bean? Kidney? Only at moderate intensity Upstream of gas flowA real surprise – this was not seen in the aging tests performed
over the last years with test modules
Ratio Plot: Iafter/Ibefore
Gas flowCarbon deposit on the surface
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Ageing: The CauseTest module:17 hrs, 2 mCi
Put fresh glue (AralditeAW103, HY991) at straw entrance of Aluminum test module
TraBond 558 hr, 20 mCi
Build full-scale module with different glue: TraBond 2115
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Beneficial Treatments
Flushing Time (weeks)
Gai
n lo
ss (%
)
L
No heating: 20 hrs 2mCi 90Sr With heating: 325 hrs 2mCi 90Sr
½ year ½ year
Preventing Treatments: 1) Long term flushing 2) Heating of the modules 3) Lowering the gas flow 4) Adding O2 to the counting
gas
2) Heating (Lab):
1) Flushing:
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Recovery Treatment
2nd HV training
1st HV training
3rd HV training Rel
ative
Gai
n
Irradiation Time (hours)
Before HV training
After HV training
Trained half
Non-trained half
HV training (24 hours, 1900 V, G~106) Dark current ~10 m A/wire Wire inspection promising:
• no carbon deposits despite large currents
Outer Tracker
Outlook OTDetector installed and alignedElectronics production being finalizedCommissioning underway Irradiation resistance studies ongoing:
Detectors being flushed and heated Investigating HV training procedure Further testing of ``TraBond module´´
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Software: Reconstruction, Trigger & Physics
NIKHEF provides Trigger deputy project leader(HLT implementation)
Nikhef Contributions:• Kalman Filter track fitting• Software Alignment: Framework, Geometry, Kalman filter implementation • HLT implementation• DaVinci and LoKi physics frameworks
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Display of LHCb simulated event
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Key measurements – NIKHEF group
• CKM Metrology: 1. Amix: Bs → Ds p Dms ACP: Bs →
Ds K g-fs
2. ACP: Bs → J/y f fs
• Rare Decays:1. Br: B(s)→mm2. Afb: B0 →K*mm , b →s mm
Looking for effects of new physics in the flavour sector:
2BD bs
sb
“Box”
Well matched to our activities:i. VeLo and OT constructionii. Track reconstruction
“Penguin”b s
1BD
4 “teams”: each with 1-2 staff, 1 postdoc, 2-3 students
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Dimuon mass resolution:Track c2/dof:
Kalman Track Fitting and Alignment Reconstruct tracks including
multiple scattering. Tracking in realistic (misaligned)
geometry. Simultaneous detector element
alignment fit and trackfit z
J/y peak— UnalignedO Aligned∆ Default
— UnalignedO Aligned∆ Default
Example: Bs→ J/y f . Simultaneous likelihood analysis
in time, mass, angular distribution domains
time
mass
cos qtr
cosqf
ftr
signalbackgsum
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Theses b-physics• Theses on LHCb:
– (2001) N. Zaitsev Pile-up and Bs→J/yf– (2002) R. v.d. Eijk OT and tracking– (2003) R. Hierck Tracking and Bs→DsK/p– (2004) N. v. Bakel Velo and Bs mixing– (2005) S. Klous Velo and Bs →J/y f– (2005) J. v. Tilburg Tracking and Bs→Ds K/p – (2006) B. Hommels Tracking and Trigger– (2007) J.Nardulli Reconstruction of two body B decays in LHCb
• Theses on Hera-B:– (2002) M. Bruinsma J/y in pA– (2002) W. Hulsbergen Track reconstruction– (2003) M. Mevius B cross-section– (2005) H. Wahlberg B cross-section– (2006) A. Sbrizzi B X-section & pentaquark
• Thesis on Babar:– (2006) M.Baak CKM angle gamma17-4-2008
Nikhef-evaluation 336-sept-2007
The B-Team
The “technical” Beauties! (the real backbone)
The mad young geniuses:The Muscles:
Those who love it when a plan comes together (the Planners):
The B-team
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Summary• Velo
– Cooling, vacuum, motion control are “ready”• The devil is in the (unforseen) detail
– PileUp detectors installed, trigger implementation requires effort– New RF-boxes being produced
• Outer Tracker– Detector installed and aligned– Electronics installation under time pressure– Irradiation studies ongoing with high priority
• Software– Reconstruction framework ready– Tracking fitting and Alignment algorithms tested– Selection and physics algorithms being developed
• Upgrade– Investigating contributions:
• Better RF boxes• Velo module replacement• OT operation under high luminosity• 40 MHz readout electronics
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The End
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The Scientific Team (NIKHEF, VU)• Scientific Staff: (~9 FTE)
– Bauer (0,5 OT), v Beuzekom (0.8, Velo), v/d Brand (0.5, Velo), Bulten (0.5,Phys), Hulsbergen (1, Reco), Jans (1, Velo), Ketel (0.5, OT/Velo), Merk (1), Pellegrino (1,OT), Raven (1,Phys), Tuning (1, OT,Phys), de Vries (0.8, Velo), Wiggers (0.7, PileUp/Upgrade)
• Post-docs:– Belyaev (Phys), Kazu (Velo/Phys), Palacios (Reco), Serra (Phys), Terrier (OT) , Van
Lysebetten (Velo)
• Graduate Students:– Amoraal (Reco), Bos (Reco), Jansen (OT), M’charek (OT/Phys), Mous (Velo),
Papadelis (Velo), du Pree (Phys), Simioni (OT/Phys), Snippe (Velo), Snoek (Babar), Storaci (OT ), Ybeles-Smit (Phys)
• Master Students:– Aaij (Reco), Hooft v. Huysduynen (Phys)
The groupStaff Members
12 people (~9 FTE) : 2(30+), 4(40+), 5(50+), 1(60+)
Postdocs 3 FOM-Nikhef, 1 FOM-PR, 1 NWO-Vidi
Technical Staff 7 (3 OT+4 Velo) Mechanics Engineers, 4 (2 OT+2 Velo) Mechanics Workshop,
8 (3 OT+5 Velo) Electronics, 1 Computing
Graduate Students 6 FOM-Nikhef, 1 FOM-BUW, 1 VU, 1 NWO-Vidi
2 Master students
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LHCb experiment in the cavern
31-3-2008 38
Shielding wall(against radiation)
Electronics + CPU farm
Offset interaction point (to make best use of existing cavern)
Detectors can be moved away from beam-line for access
b-b in LHCb
31-3-2008 39
LHCb event rate: 40 MHz1 in 160 is a b-b event
Background SupressionFlavour taggingDecay time measurement
• vertices and momenta (mass) reconstruction • effective particle identification (π, К, μ, е, γ)• triggers
qb
qb