Sotiris Vlachos BGV Status and Plans

The BGV core Team BE-BI-BL LHCb M. Ferro-Luzzi B. Dehning C. Barschel A. Alexopoulos E. Bravin B. Würkner Q. Veyrat S. Vlachos (+ considerable support from the BE-BI community) LHCb M. Ferro-Luzzi C. Barschel O. Girard G. Haefeli P. Hopchev R. Jacobsson A. Kuonen M. Rihl (+ considerable support from the LHCb community) Full collaborator list: https://twiki.cern.ch/twiki/bin/view/BGV/Project_Organization#Author_List 24/11/2016 S. Vlachos

Demonstrator built around Beam 2, in Pt4 Beam Gas Vertex Detector Non destructive beam size measurement for HL-LHC not limited by accelerator luminosity Tracks from beam-gas interactions to reconstruct beam spot, Ne @ 10-8 mbar injected at interaction volume Should allow beam spot size (and hence ε) measurements with precision <10% (5 minutes integration time) Demonstrator built around Beam 2, in Pt4 Expect first real-time beam profile measurements for 2017 pp runs 24/11/2016 S. Vlachos

Beta functions in LHC point 4 at ~ -220m , beam 2 has x  y  150 m at 7TeV and N  2.5μm, beam  0.22 mm 24/11/2016 S. Vlachos

More information Details on detector requirements and description of subsystems can be found at: https://twiki.cern.ch/twiki/pub/BGV/Presentations/2015_11_1 9--BITechBoard.pdf (BE-BI TB presentation Nov 2015) In addition all BGV information can be found in the dedicated twiki page : https://twiki.cern.ch/twiki/bin/view/BGV/WebHome 24/11/2016 S. Vlachos

DETECTOR STATUS 24/11/2016 S. Vlachos

BGV Status and Plans Summary Demonstrator Status Detector fully commissioned SciFi detector planes Read-out chain and CPU farm Trigger system Control and DAQ s/w Cooling system functional, detector @ -25℃ Dead channels ~ 0.3% Gas injection system operational Several data-taking campaigns during 2016 with various beam conditions Off-line analysis in good progress Next steps Offline analysis: high precision track and vertex reconstruction Implement analysis software in the BGV online CPU farm for real-time beam profile measurement Establish data logging and measurement publishing towards CCC Further upgrades for BGV demonstrator: Faster trigger electronics + extra scintillators for optimal Beam2 identification Additional fast detector plane (time resolution ~40ps) for z profile reconstruction 24/11/2016 S. Vlachos

BGV Control and Operation A typical entry from the BGV e-log: 24/11/2016 S. Vlachos

(i.e. 25ns coincidence window) BGV Trigger Veto Counters L0 Counters (i.e. 25ns coincidence window) 1500V 1800V Scintillator Relative timing Scintillator Amplitudes 24/11/2016 S. Vlachos

BGV read-out TELL1 : Cluster finder (zero-suppression) HLT farm : Full reconstruction program Currently reading out non zero suppressed data to define optimal algorithms (hence R/O rate limited to ~ 1KHz) Full (16 blades) HLT farm and ZS data will allow a DAQ rate of ~1MHz 24/11/2016 S. Vlachos

Cooling System Julabo Chiller in service tunnel and all piping to BGV detector installed. Detector currently operating @ -25℃ Cooling fluid leak rate < 200ml/month : Can safely operate between TSs Next steps: Incorporate Chiller control in BGV WinCC system for monitoring and data logging Dry Air interlock Cooling system Upgrade if lower temperatures are needed: Install closed circuit for C6F14 with heat exchanger and secondary cooling with chiller   24/11/2016 S. Vlachos

DATA ANALYSIS 24/11/2016 S. Vlachos

Estimation of beam spot size Three methods under study to analyze BGV data Approximate beam-gas vertices by finding close-by tracks (fastest approximation) Use track and impact parameter correlations to measure beam position and width (accurate measurement without vertex fitting) Exact vertex reconstruction(most precise method) 24/11/2016 S. Vlachos

Track reconstruction – Real data 24/11/2016 S. Vlachos

Distance of closest approach (DOCA) ɸ d (Distance Of Closest Approach) x y REAL DATA This is a x-y projection of the beam-gas interaction volume. DOCA is calculated in 3-d and hence one obtains also a POCA (Point of Closest approach) : (x,y,z) Calculation done with respect to (0,0,z) 24/11/2016 S. Vlachos

Beam-gas interactions POCA z-distribution 24/11/2016 S. Vlachos

DOCA based vertex approximation Vertex seed : a pair of tracks with relative DOCA < 1mm Add tracks with relative DOCA < 1mm and form new seed until list of tracks is exhausted Use each track only once Monte-Carlo Simulation Beam @ (1,1) with σ = 0.15mm Real Data Blue: Generated, Black: Reconstructed (x,y) 24/11/2016 S. Vlachos

Beam position and DOCA-ɸ correlation Real primary vertex position (instead of (0,0)) ɸ DOCA y0 DOCA = x0sin(ɸ) – y0cos(ɸ) x0 24/11/2016 S. Vlachos

Simulation results DOCA vs ɸ Beam spot generated @ (0,0) Reconstructed @ x = 0.001 mm y = 0.005 mm Beam spot generated @ (1,1) Reconstructed @ x = 0.84 mm y = 0.81 mm Note: Outliers cause underestimation of (x,y). Need better fitting function or calibration 24/11/2016 S. Vlachos

Real Data measurement: DOCA vs ɸ NO ERROR ESTIMATION GIVEN PRELIMINARY Beam spot reconstructed @ ~(o.01mm, 0.01mm) NOTE: No alignment corrections implemented yet 24/11/2016 S. Vlachos

DOCA correlation vs σbeam The event-by-event displacement due to finite σbeam affect all particles of a beam-gas interaction in the same way. Hence their DOCAs are correlated: <DOCA1DOCA2> = (σx2+σy2)cos(ɸ1-ɸ2)/2 + (σy2-σx2)cos(ɸ1+ɸ2)/2 σx (σy) being the beam spot variance along x (y) Assuming σx = σy : <DOCA1DOCA2> = (σbeam2)cos(ɸ1-ɸ2) Correlation does not depend on DOCA resolution (assuming all tracks come from the interaction vertex) 24/11/2016 S. Vlachos

DOCA correlation → σbeam Monte Carlo Simulation Real Data NO ERROR ESTIMATION GIVEN PRELIMINARY Generated σbeam = 0.15mm Fitted σbeam = 0.2mm REAL DATA Fitted σbeam = 0.2mm (Above distribution is yet an other indication of reconstructed tracks far from the interaction vertex) 24/11/2016 S. Vlachos

Analysis Next steps Refine tracking performance – reduce outliers, improve efficiency Use MC samples to estimate error and systematics on beam spot size and position estimation Study detector coverage and method efficiency Implement all necessary alignment corrections Increased statistics and z-segmentation In addition: Verify zero-suppression algorithm to be implemented in h/w 24/11/2016 S. Vlachos

Plans for 2017 Collect large data samples (with correct timing and trigger settings) Optimize beam spot measurement Implement measurement algorithm in HLT farm Set-up communication with CCC Increase number of CPU blades in HLT farm to allow for real-time measurements Finalize ZS algorithm and program it in VHDL 24/11/2016 S. Vlachos

BGV UPGRADES 24/11/2016 S. Vlachos

BGV Upgrades Trigger Upgrade New front-end electronics CF discriminators VME logic board for coincidence in narrow time window Additional Scintillators Downstream to identify B2 (and separate from B1) Additional fast detectors: MicroMegas based strip detector with ~40ps time resolution to allow reconstruction of beam bunch along z 24/11/2016 S. Vlachos

BGV Trigger Upgrade L0 Counters Veto Counters L0 Confirm New trigger electronics CF Discriminators Delay and coincidence logic (~10ns coincidence window) Additional scintillators (L0 confirm) 24/11/2016 S. Vlachos

MicroMegas ps detector For reconstructing the z profile of a beam bunch : need ~60ps resolution MM: small amplification gap (50-150 μm) fast signals (~ 1 ns) short recovery time (~50 ns) high rate capabilities (> MHz/cm2) high gain (up to 105 or more) Time resolution already achieved: <50ps Anode can be in the form of wide (~cm) strips to match the BGV geometry To be placed possibly at the L0 confirm support frame For more details see BE-BI seminar: MicroMegas detector applications for beam diagnostics https://indico.cern.ch/event/540799/ 24/11/2016 S. Vlachos

Summary BGV H/W fully deployed – commissioned Beam spot reconstruction Encouraging first results Expected optimal resolution with full vertex reconstruction Open issues: Transport offline code to online system Communication with CCC BGV upgrades and deployment for B1 24/11/2016 S. Vlachos

BackUp 24/11/2016 S. Vlachos

24/11/2016 S. Vlachos

Radiation monitoring 6 PIN Diodes measuring directly on detector modules Expected dose ~10Gy/year (more details: https://twiki.cern.ch/twiki/bin/view/BGV/Radiation 24/11/2016 S. Vlachos

BGV module Test Beam Measurements Courtesy: O. Girard - EPFL 24/11/2016 S. Vlachos

DOCA – phi projection MC(1,1) 24/11/2016 S. Vlachos