Technology of the TOTEM Roman Pots and Future Detectors Upgrade

Transcription

1 17th Lomonosov Conference оn Elementary Particle Physics Moscow State University, August 20-26, Technology of the TOTEM Roman Pots and Future Detectors Upgrade D. Druzhkin (CERN), on behalf of TOTEM collaboration o

2 Roman Pot (RP) detectors are installed on LHC accelerator close to Interaction point (around the large central detectors CMS and ATLAS). It is a precision proton tracking and timing detectors in the very forward region on both sides of central Detectors, to study the forward physic in proton-proton collisions. The idea is to bring the detector as close as possible to the circulating beam. The LHC magnets between the Interaction Point (IP) and the RP detectors (at ~ m from the IP) form a magnetic spectrometer to analyse protons that have lost a small fraction of their initial momentum and travel out of the Beam envelope. It is new tool increasing the potential of central Detector and of own physical program in the search for New Physics. TOTEM concept: Proton spectrometer making use of machine magnets 1) Four tracking stations with Si strips detectors (2 vertical RP + 1 horizontal RP per station, installed); 2) Four vertical RP with 50 ps timing detectors, (upgrade) 3) Timing reference system (upgrade). CT PPS concept: (upgrade) Proton spectrometer making use of machine magnets 1) Four tracking stations with 3D pixel detectors 2) Two stations with 10 ps timing detectors 3) Timing reference system. Instrumented extension for the central detector Use timing to reject pileup background (time difference of two protons is correlated to collision vertex); Low and High level trigger for central detector. See a presentation of Christophe Royon in this conference Program: TOTEM precise measurement of the total, elastic, inelastic pp cross section; soft diffraction TOTEM and CMS (Run1) Soft diffraction, inclusive hard diffraction, particle multiplicities; Measurement of the pseudorapidity distribution of charged particles in proton proton collisions; Inclusive Hard Diffraction; TOTEM and CMS (upgrade, Run2) Low mass resonances and glueball states in central diffraction. Exclusive central production. Search for missing mass candidates. Exclusive central diffraction jet productions. CT PPS Study central exclusive production (CEP) in proton proton collisions at high luminosity, such as new physics via anomalous production of W and Z boson pairs, high pt jet production, and possibly the production of new resonances. LHC Forward Physics (together with other LHC detectors) CERN/LHCC 2015, July

3 Physics motivations, TOTEM and TOTEM+CMS Diffractive Physics Program LHC Run II TOTEM: standard measurement of elastic scattering (from the largest to the smallest t) and of the total and inelastic cross section at the new LHC energy (13TeV; 14TeV) TOTEM+CMS: physics search on low mass spectroscopy (1 3GeV) gluonic states and glueball searches diffractive c production TOTEM+CMS: central diffractive jet production 2 TOTEM+CMS: missing/escaping mass ln s 1,2 1,2, M 1 2 Preliminary investigation of some physics channels in progress with the analysis of data from joint CMS TOTEM high * run (90m), 8 TeV,July 2012 See: Timing Measurements in the Vertical Roman Pots of the TOTEM Experiment (TDR). CERN LHCC X, 26 May 2014 N. Turini, 10 jul

4 Physics motivations, CT PPS detector Exclusive WW 10 ps Inclusive WW ToF vs. z vertex J.Varela Physics with CT PPS, LISHEP 2015, Manaus PPS LISHEP2015.pdf 4

5 LHC Optics: RP sensitivity Optics parameters from data: full non-linear fit, harmonics, displacements, Hit maps of simulated diffractive events for 2 optics configurations ( * = betatron function at the interaction point) * = 0.55 m (low * = standard at LHC) * = 90 m (special development for RP runs) t = p 2 L x = 1.7 m, L y = 14 m, D x = 8 cm diffractive protons: mainly in horizontal RP elastic protons: in vertical RP near x ~ 0 sensitivity only for large scattering angles p/p y = L y y + v y y* x = L x x + D + v x x* L x = 0, L y = 260 m, v y = 0, D x = 4 cm diffractive protons: mainly in vertical RP elastic protons: in narrow band at x 0, sensitivity for small vertical scattering angles Beam vertex Angular beam divergence Min. reachable t * ~ m small large ~ GeV 2 * 2 * n * n n p * x, y (, ) * = 90 m large x y tmin n p m * small ~ 10 GeV 2 See in detail: /16/10/103041/ N.Turini 10 jul 2015

6 Commissioning programme in 2015: RPs insertions & commissioning TOTEM data taking in 2015: Study beam losses / showers and interplay with TCL collimator system - compare BLMs upstream and downstream of TCL6 - if needed adjust XRP BLM thresholds upstream of TCL6 Special b* = 90 m run LHC schedule Study RP impact on impedance: heating: additional temperature sensors in RPs vacuum: 4 gauges in our sector beam orbit stability: monitored by impedance group Start with low intensity fills and follow the lumi ramp up: Alignment after TS1 (26 individual pots) Validation of positions with loss maps End of fill RP insertions how it is far from the center of a proton beam : * = 0.8 m Vertical Horizontal Plan on early settings TCT mm = (19 21) TCT mm = (25 30) final settings * = 0.6 m * = 0.6 m TCT + 4 = TCT + 7 = mm) 6

7 Roman Pots on LHC Roman Pot station m LHC magnets CMS IP Roman Pot Stations (LSS 4-5) LHC Ring Roman Pot Stations (LSS 5-6) LHC magnets Roman Pot station m The Roman Rots in LHC tunnel beam In beam out Alfa AFP 7

8 Roman Pots detectors (CT PPS & TOTEM) installed in LHC tunnel CERN, 2015 IP5 TOTEM tracking CT-PPS tracking 2 CT-PPS tracking 1 CT-PPS timing Collimators TCL 4 & TCL 6 TOTEM upgraded detectors (12 RPs) New CT-PPS detectors ( RPs) New BP elements: vacuum chambers, ionic 8 pumps and cartridges, BLMs,

9 Roman Pot Detectors General structure of Roman Pot station LHC Beam pipe Vacuum bellow Housing for detector Returnable springs Of the safety system Step motor Sliding mechanism Vacuum compensation system Horizontal RP BPM Two vertical RP 9

10 1) TOTEM RP, silicon microstrip tracking (installed on LHC from 2008) 10 layers of silicon microstrip plates: - edgeless on the beam side; fully efficient at 50 micron from edge - position precision of 10 μm; - space resolution - 10 μm, angle resolution - 1μrad; - Δp/p ~ , Mass resolution: ~2 GeV/c2 (depends on the optics); - Radiation hard close to beam (~ n eq /cm2) for 100 fb -1 ; To improve the multitrack resolution one of tracking Pot is rotated by 8 The step motor is the one used for the LHC collimators. 5um per one steps, 400 steps per one turn. See: Performance of the Totem Detectors at the LHC CERN PH EP arxiv: [physics.ins det] Int. J. Mod. Phys. A 10

11 2) TOTEM diamond timing detector Detector : - Dimension of a plane 10mmx18mm, 500 μm thick; - 8 pixels with segmentation adapted to the track density; - A stack of 4 Planes improves the single plane timing resolution; - final time resolution of ~50 ps (Measure time of arrival of proton with a resolution better than 50ps); - Low occupancy to reduce inefficiency due to double hit in the same detector; - High efficiency up to the edge. X(mm) Diamond detector signal N.Turini, M.Beretti Timing Measurements in the Vertical Roman Pots of the TOTEM Experiment (TDR). CERN LHCC X, 26 May

12 2) TOTEM diamond timing detector Location in the Roman Pot Cooling radiators N.Turini, M.Beretti 12

13 3) Fast Timing detectors QUARTIC (CT-PPS) Baseline: Cherenkov detectors with quartz (sapphire) radiators L-bars and Silicon PMs (radiation issues) 1) Excellent time resolution (σ(t) ~ 10 ps) 2) Edgeless on beam side (Δx <~ 200 μm) 3) Radiation hard close to beam (~ p/cm 2 ) 4) Fast readout (25 ns crossings) & trigger signal 5) Segmentation (multi-hit capability) 6) Detector is a 4 x 5 array of quartz (sapphire) bars, 3 x 3 mm 7) Two such modules in one Roman pot in each arm. 8) L-bar geometry allows SiPMs to be 70 mm from the beam Beam tests achieved σ(t) = 30 ps/module (30 ps/ 4 = 15 ps for 4-in-pot) 13 σ(δt(pp)) 15 ps => σ(z(pp) = 2.25 mm

14 3) Fast Timing detectors QUARTIC (CT-PPS) QUARTIC inside of the Roman Pot Two QUARTIC modules QUARTIC block Hodoscope of 3 x 3mm independent elements

15 3) Fast Timing detectors QUARTIC (CT-PPS) Garage position Run (10σ) position 1.4mm(10σ) Cylindrical Housing (Inox 316LN) Thin window 2mm 2mm mm 0.3mm 15

16 The passage of the beam produces electromagnetic fields that interact with the vacuum chambers (beam pipe, roman pots, etc.) and can lead to: Beam instabilities Excessive Heating of the equipment Bean energy loss Excessive heating Impedance Cylindrical or RF shield Box design without RF shield N.Minafra 16

17 150um Rectangular RP housing with Rectangular RP housing (20um planarity) Faraday cage (RF shield) Cylindrical RP housing circular ferrites Cu 2mm Ferrite support spring NIVAFLEX baked-out Transtech TT2-111R ferrites with better outgassing behaviour and a higher Curie temperature. circular ferrites New bellow & vacuum chamber with circular ferrites electron cloud NEG coating of the inner vacuum surfaces: - to improve the vacuum - to reduce the electron clouds 17 17

18 Radiation environment J.Varela The conditions for β*= 90m run are softer BRIL 18

19 The clock distribution time resolution ~ 1 ps 1) - TOTEM webpage 2) REFERENCE TIMING SYSTEM FOR CMS TOTEM PPS PROJECT (ECR) N.Turini 10 jul 2015 Special fast electronics are developing for these detectors (SAMPIC, HPTDC, FPGA,.) 19

20 Upgrade 1. Timing detectors: - New Diamond detectors, demonstrated 50 ps -GasTOF, σ(t) ~ 10 ps, radiation hard - UFSD - Ultra Fast Silicon Detector, σ(t) ~ 60 ps (INFN Torino ); ( - Hyperfast Silicon Detector, σ(t) ~ 16 ps 2. 3D silicon pixel tracking detectors (CT-PPS); New hard radiation 3D Si sensor (Nicolo Cartiglia, Michele Arneado, Maria Obertino INFN Torino and CERN); ( challenge is fluence 5x10 15 protons.cm -2 (100 fb -1 ) 3. MBP (HBP) 4. Reference clock system < 1 ps; (Nicola Turini, Michael Bousonville, CERN, DESY) 20

21 References TOTEM webpage CMS TOTEM Memorandum of Understanding (January 2014 ) CMS TOTEM Precision Proton Spectrometer (TDR) CERN LHCC / CMC TDR 013, TOTEM TDR 003, 8 Sept TOTEM Consolidation Project (ECR) LHC XRP EC 0010, EDMS , TOTEM Upgrade Proposal: CERN LHCC / LHCC P 007, 12 June 2013 TOTEM Upgrade Project (ECR) LHC XRP EC 0011, EDMS , (draft) Timing Measurements in the Vertical Roman Pots of the TOTEM Experiment CERN LHCC , TOTEM TDR 002, 15 Sepr Performance of the TOTEM detectors at the LHC World Scientific, Vol. 28, No. 31 (2013) , DOI: /S X A luminosity-independent measurement of the proton-proton total cross-section at sqrt s = 8 TeV CERN PH EP Phys. Rev. Lett. 111, (2013) LHC Optics Determination with Proton Tracks Measured in the Roman Pots Detectors of the TOTEM Experiment CERN PH EP , New J. Phys. 16 (2014) THANKS! 21

22 Roman Pot Detector Acceptance 22

23 7 TeV elastic differential cross section d el / dt Ae B t A= syst 1.0 stat mb/gev 2 A = syst 1.5 stat mb/gev 2 B= syst 0.04 stat GeV -2 t dip = 0.53 GeV 2 ~ t 7.8