Download pdf - The$upgrade$program$of$the$LHCb$ … · The$upgrade$program$of$the$LHCb$ experimentatthe$Large$Hadron$ Collider$ Rudolf$Oldeman$ INFN$Sezione$di$Cagliari$$ and$Università$di$Cagliari$

The upgrade program of the LHCb experiment at the Large Hadron

Collider Rudolf Oldeman

INFN Sezione di Cagliari and Università di Cagliari

On behalf of the LHCb collaboraCon

27/9/2013 XCIX Congresso Nazionale della SIF -‐ Trieste 1

The Large Hadron Collider


Collides protons on protons head-‐on with Ecm=8 TeV every 50ns (13 TeV, 25ns in 2015)

The LHCb experiment


~1/100 pp collisions produces b hadron decays in few ps (~few mm)

Cherenkov detectors

Tracking

calorimeters

~600 physicists from ~20 countries

muon detector

performance parameters: * 2<η<5 * σPV,xy~10μm * Δp/p 0.4%-‐0.6% * P(h→μ)~1%

LHCb trigger and readout •  Maximum readout rate: 1MHz •  Hardware trigger requires high-‐E µ or h

•  ~90% eff for B→µ+µ-(X) •  ~30% eff for B→hadrons •  ~10% eff for charm

•  full reconstrucCon @1MHz in 30k CPU ‘farm’ •  pp bunch crossing every 50 ns (25ns in 2015) •  with ~2 collisions each

–  kept constant though luminosity levelling –  achieved by displacing beams at coll. point

•  ‘opCmum’ L=4x1032cm-‐2s-‐1 –  rise in trigger threshold would overshadow gains


LHCb highlights from 2011-‐2012 data

27/9/2013 XCIX Congresso Nazionale della SIF -‐ Trieste

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•  Strong evidence for Bs→µ+µ- decays arXiv:1307.5024

•  CP-‐violaCng phase

LHCb-‐CONF-‐2013-‐006

•  ObservaCon of D0 mixing PRL 110, 101802(2013)

•  and 135 other published results... –  See talks of S Perazzini, L. Anderlini, A.A.Alves Jr., M Zangoli and S. Amerio at this conference

Timeline

•  2011: 1p-‐1 at Ecm=7TeV, 50ns b-‐b •  2012: 2p-‐1 at Ecm=8TeV, 50ns b-‐b •  2013-‐2014: LS1 (first long shutdown) •  2015-‐2017: 5p-‐1 at Ecm=13TeV 25ns b-‐b •  2018: LS2 INSTALL LHCb UPGRADE •  2019-‐2021: 15p-‐1 •  2022-‐2023: LS3 (third long shutdown) •  2024-‐??: 10p-‐1 per year


LHCb upgrade requirements

•  instantaneous luminosity (1-‐2)x1033cm-‐2s-‐1 – on average 5 collisions per bunch crossing –  integrated luminosity 50p-‐1

•  full detector readout at every bunch crossing –  to cope with higher luminosity – doubles B-‐>hadron efficiency


Challenges •  Fine segmentaCon

–  to cope with <n>=5 •  RadiaCon hardness

–  50p-‐1 •  Low mass

–  equal to or less then current •  Fast readout

–  40MHz •  Tremendous dataflow

–  40Tb/s •  Complex networking for event building

–  12k fibers to 50k CPU •  CompuCng power

–  full event reconstrucCon @ 1-‐40MHz


The LHCb upgrade


kept parCally kept replaced removed

VELO upgrade: strips -‐> pixels 55x55µm, 40Mpixel Thin (200µm) sensor, ASIC 26 layers, 0.8%X0 each micro-‐channel CO2 cooling -‐20oC RF foil thinner: 300-‐>150µm, Si closer to beam: 8-‐>5.2mm


The upstream tracker (UT)

•  To replace the present TT –  large-‐area tracking upstream of dipole magnet

–  long lever arm improves dp/p –  Crucial for Ks→π+π-‐, Λ→pπ-‐

•  Keep 4 layers (0o,+5o,-‐5o,0o) •  Thin (250µm) sensors, -‐5oC •  Challenge for material budget <5%X0 •  smaller pitch, length near center •  Inner sensors circular cut


Downstream tracking

•  3x4 planes 5x6m2

•  present: IT(Si)+OT 4mm tubes (50ns dri{ Cme) •  Too high mulCplicity for upgrade condiCons •  Two opCons under consideraCon: – more silicon, shorter tubes – parCal or complete replacement with fiber tracker


larger IT opCon


•  Increase fracCon of surface covered by Silicon •  remake part of OT with shorter straws

ultra light-‐weight support structure

present half IT

half IT in upgrade

ScinCllaCng fiber opCon now baseline op<on

•  5-‐layer 250µm fibers. – 2.5m long, mirrored ends – 8000km to cover 12x (5x6m2)

•  SiPM (1100x250µm) readout @ -‐50oC


Ring Imaging Cherenkov detectors RICH1 aerogel+C4F10 RICH2 CF4

•  Present: Hybrid photodetectors –  silicon pixel inside image intensifier –  pixel readout <=1MHz –  need replacement

•  New choice: ‘classic’ 8x8 MulC-‐Anode PMTs –  square shape-‐>be|er surface packing than

cylindrical hybrids

•  Remove aerogel from RICH1 •  Increase radius of mirrors 2.7→3.8m

–  both reduce occupancy •  In LS3: TOF (TORCH) system behind RICH2 to

recover low-‐p PID?


Calorimeter

•  remove two ‘thin’ detectors in front of ECAL –  ScinCllaCng pad detector, SPD –  preshower, PRS

•  not needed in 40MHz readout •  reduce PMT HV to reduce ageing –  5x gain reducCon

•  New low-‐noise high-‐gain frontend with 40MHz readout

•  replace some inner modules in LS3


Muon system

•  Remove pre-‐CALO staCon M1 – was only used for trigger

•  New off-‐detector electronics for 40HMz readout

•  Replace some inner modules at LS3


Readout&trigger

•  ~12k opCcal fibers with 3.2Gb/s each •  Straight to the surface –  present LHCb has most electronics in cavern

•  Common readout board •  Full event reconstrucCon in farm •  IniCally, farm won’t be able to handle 40MHz •  Use exisCng hardware trigger (L0) as rate limiter (LLT) 10-‐40MHz

•  Allow 20kHz to ‘tape’


Physics prospects


Many key measurements have small SM theory uncertainCes

Conclusion

•  LHCb is preparing for major upgrade for 2019 •  ‘Triggerless’ readout and higher granularity •  Aim to run at 5xluminosity, 2xefficiency (for h) •  AcCve R&D to make final technology choices •  ImperaCve to reach full sensiCvity to new physics in the flavour sector at the LHC


BACKUP 27/9/2013 XCIX Congresso Nazionale della SIF -‐ Trieste 21

Documents

•  Expression of Interest CERN-‐LHCC-‐2008-‐007 •  Le|er of Intent CERN-‐LHCC-‐2011-‐001 •  Framework TDR CERN-‐LHCC-‐2012-‐007
