10th particle physics conference Upgrade of electronics and corresponding calibration procedure for STAR time-of-flight detector Ming SHAO USTC 2018/11/20 10th particle physics conference

STAR physics program and TOF upgrade Near term TOF Long term Thermometers: dilepton, photon heavy quarkonium species. jet fragments tagged by a hard direct photon, a heavy flavor elliptic flow in U+U collisions. LHC and GSI energies fundamental QCD symmetries v2 scaling for coalescence jet quenching as parton energy loss energy dependence testing model prediction Heavy flavor yields and flow: color screening and partonic collectivity forward jet correlation: CGC ID-particle spectra freeze-outs hadronization ID-particle correlations In-medium jet Fluctuations and correlations Lepton program In-medium vector meson Heavy Flavor Baseline detector for future upgrades Identified hadron spectra freeze-out dynamics hadronization mechanism Identified particle correlations Chemical and kinetic properties of in-medium jet associated spectra Fluctuations and correlations Lepton program In-medium vector meson properties Heavy flavor Baseline detector for future upgrades Near/Long Term: STAR white paper, Nucl. Phys. A 757 (2005) 102 2018/11/20 10th particle physics conference

What can we get from TOF (I) - Resonance decay /p misidentified as K Suppress background Rare particle searching Increase S/B, decrease data sample size 130GeV AuAu 2018/11/20 10th particle physics conference

10th particle physics conference What can we get from TOF (II) - Open charm - Fluctuation <pT> fluctuation 3 signal (D0+D0bar) 2018/11/20 10th particle physics conference

10th particle physics conference What can we get from TOF (III) - RHIC energy scan K+/+ v1, v2 v2 fluctuation, <pT> fluctuation … All benefit from a nearly complete direct PID 2018/11/20 10th particle physics conference

MRPC TOF (TOFr) – stop time measurement pVPD - start time measurement Detectors -PID TPC- tracking Particle momentum; dE/dx ~8% resolution /K separation to ~0.6GeV/c K/p separation to ~1.0GeV/c MRPC TOF (TOFr) – stop time measurement pVPD - start time measurement Aim at 100ps time resolution TOF system /K separation to ~1.6GeV/c & K/p separation to ~3.0GeV/c 2018/11/20 10th particle physics conference

10th particle physics conference TOF system pVPD consists of plastic scintillator + fast PMT, 5.4m from TPC geometry center along the beam line 3 channels each side (run5 and before) upgrade to 19 channels each side (after run5) Full barrel TOF consists of 120 trays, 32 MRPC modules per tray, 6 channels (strips) per module Only one tray in run5 2018/11/20 10th particle physics conference

10th particle physics conference TOF Trays along years run5 run4 run3 Better mechanical design Simpler fabrication improved tolerance Optimized electronics 2018/11/20 10th particle physics conference

10th particle physics conference TOF DAQ Before run5 Run5 and later Peripheral Component Interconnec/interfacet，周边元件扩展接口 Source Interface Unit Read Out Receive Card NIM local trigger based on pVPD signals CAMAC digitalization w.r.t local trigger I/O via PCI board and to STAR over network Slewing via ADC No local trigger HPTDC digitalization w.r.t clock (time stamps) I/O via SIU/RORC fiber directly to STAR Slewing via Time-Over-Threshold (TOT) 2018/11/20 10th particle physics conference

Tray Level Electronics 2 THUB per side, 4 total 1 TCPU per tray/pVPD, 122 total 1 TPMT/TDIS per pVPD, 2 total 8 TINO/TDIG per tray, 960 total 24 chn. per TINO/TDIG, 23040 total 2018/11/20 10th particle physics conference

HPTDC Time Measurement HPTDC is fed by a 40 MHz clock giving us a basic 25 ns period (coarse count). A PLL (Phase Locked Loop) device inside the chip does clock multiplication by a factor 8 (3 bits) to 320 MHz (3.125 ns period) . A DLL (Delay Locked Loop) done by 32 cells fed by the PLL clock acts as a 5 bit hit register for each PLL clock (98 ps width LSB = 3.125 ns/32). 4 R-C delay lines divide each DLL bin in 4 parts (R-C interpolation) Coarse time (bin width 25 ns, 11 bits) PLL bits (bin width 3.125 ns) DLL bits (bin width 98 ps) MSB LSB R-C bits (bin width 24.4 ps) 2018/11/20 10th particle physics conference

10th particle physics conference Run5 Setup 2018/11/20 10th particle physics conference

10th particle physics conference Run5 Setup 2018/11/20 10th particle physics conference

10th particle physics conference Run5 Setup 2018/11/20 10th particle physics conference

10th particle physics conference Run5 Setup 2018/11/20 10th particle physics conference

10th particle physics conference Run5 Setup 2018/11/20 10th particle physics conference

TOF Calibration – run5 (and later on) Data sample (after TOF matching): ~8.4M from CuCu 62.4GeV, ~4.3M from CuCu 200GeV Leading-edge discrimination : timing signal Trailing-edge discrimination: signal width (TOT) time Amp. T1l T2l T2t T1t Thre. Time stamp MRPC strip Readout 2018/11/20 10th particle physics conference

Calibration procedure Choose  sample by limiting dE/dx and momentum range (or pre- calibrated TOF) Use spline fit (3rd polynomials TSplineFit based on ROOT developed by François-Xavier Gentit) pVPD calibration (start time) TOFr Cell_by_cell TOT and Z position calibration, using charged pion sample. Iteration several times (if needed) 2018/11/20 10th particle physics conference

10th particle physics conference pVPD TOT Correction 2018/11/20 10th particle physics conference

TOT slewing pattern (I) Module: 1, 2, 3, 4 tof - texpect TOT (ns) 2018/11/20 10th particle physics conference

TOT slewing pattern (II) Module: 17, 18, 19, 20, 25, 26, 27, 28 tof - texpect TOT (ns) 2018/11/20 10th particle physics conference

TOT slewing pattern (III) Module: 5, 6, 7, 8, 21, 22, 23, 24, 29, 30, 31, 32 tof - texpect TOT (ns) 2018/11/20 10th particle physics conference

Hit position (Z) corrction 2018/11/20 10th particle physics conference

10th particle physics conference TOF Time Resolution CuCu 62.4GeV CuCu 200GeV 2018/11/20 10th particle physics conference

TOF Time Resolution Summary Run3 to run5 Operation conditions Time Resolution (ps) pVPD TOFr (overall) TOFr (stop time) Run3 200GeV d+Au ~85 ~120 200GeV p+p ~140 ~160 ~80 Run4 62GeV (Au+Au) ~55 ~105 ~89 200GeV (Au+Au) FF/RFF ~27 ~86(74) ~82(70) HF ~20 ~82(74) ~80(71) Run5 200GeV Cu+Cu (TOT) ~ 50 ~92 ~75 62GeV Cu+Cu (TOT) ~ 82 ~125 ~94 2018/11/20 10th particle physics conference

Hadron/electron/muon PID capability |1/β-1|<0.03 electrons Hadron PID: (, K) ~1.6 GeV/c , p ~ 3 GeV/c. STAR Collaboration, PLB 616 (2005) 8 Clean electron PID can be obtained up to PT< 3 GeV/c.  This is used to measure the semileptonic decay of open charm. STAR Collaboration, PRL94 (2005) 062301 Significantly reduce the systematic uncertainty on the charm cross section measurement. STAR Collaboration, PLB 639 (2006) 441 2018/11/20 10th particle physics conference

10th particle physics conference Physics from TOF (I) Cronin effect High pT /p STAR Collaboration: PLB 595 (2004) 143 PLB 616 (2005) 8 PLB 637 (2006) 161 PRL 97 (2006) 152301 PLB 655 (2007) 104 2018/11/20 10th particle physics conference

10th particle physics conference Physics from TOF (II) STAR Collaboration, PRL 94 (2005) 062301 STAR Collaboration, PLB 639 (2006) Open charm 2018/11/20 10th particle physics conference

10th particle physics conference Summary and outlook New STAR-TOF electronics tested in recent physics runs. Technical details are verified, close to final design and waiting for production. Calibration procedure re-newed according to electronics upgrade. Consistent performance , esp. time resolution of ~80ps, is obtained. Rich physics from TOF, more in the future… Coming soon Half barrel TOF (60 trays) at run9 Full barrel TOF (120 trays) at run10 Fully commissioned at run11 2018/11/20 10th particle physics conference

10th particle physics conference Backup Slides 2018/11/20 10th particle physics conference

HPTDC Buffering & Readout 8 channel @ 25ps or 32 channels @ 100ps Level-0 Trigger Bunch Crossing Hit Buffer Level-0 Buffering 2018/11/20 10th particle physics conference

Front-End Electronics “TINO” ALICE NINO Chip 8 per tray 960 total Parameter Value Peaking time 1ns Signal Range 100fC – 2pC Noise (with detector) < 5000 e- rms Front edge time jitter <25ps rms Power consumption 30 mW/ch Discriminator threshold 10fC to 100fC Differential Input impedance 40Ω< Zin < 75Ω Output interface LVDS 2018/11/20 10th particle physics conference

10th particle physics conference MRPC Digitizer “TDIG” 8 per tray 960 total 2018/11/20 10th particle physics conference

10th particle physics conference INL Correction Sigma = 0.9 timebins = 22 ps Implies single channel resolution of 16ps 2018/11/20 10th particle physics conference

Tray Controller “TCPU” 1 per tray 1 per Start Detector 122 total 2018/11/20 10th particle physics conference

DAQ/Trigger Interface “THUB” 2 per Detector side 4 total 2018/11/20 10th particle physics conference

10th particle physics conference PMT Input Board “TPMT” 1 per Start Detector 2 total 2018/11/20 10th particle physics conference

START Detector Digitizer “TDIS” 1 per Start Detector 2 total 2018/11/20 10th particle physics conference

ALICE DDL Link Front-end electronics Source DDL SIU Interface Unit Optical Fibre ~200 meters Detector Data Link Destination Interface Unit DDL DIU Read Out Receiver Card RORC PC Data Acquisition PC 2018/11/20 10th particle physics conference

10th particle physics conference Hadron PID 2018/11/20 10th particle physics conference

10th particle physics conference Electron PID 2018/11/20 10th particle physics conference

10th particle physics conference Muon PID 2018/11/20 10th particle physics conference

10th particle physics conference Run-VIII PID 1.2<p<1.4 GeV/c 2018/11/20 10th particle physics conference

Calibration Procedure – run4 Leading-edge trigger, signal charge (ADC) is measured for correction time Amp. T1 T2 Thre. Q1 Q2 2018/11/20 10th particle physics conference

pVPD Calibration – start time 2018/11/20 10th particle physics conference

TOFr Calibration – MRPC TA & TZ TA slewing correction Hit position (TZ) correction 7th-order polynomial 2018/11/20 10th particle physics conference