Status report of the LHCf experiment: preparation for data taking Commissione Nazionale Scientifica I Pisa, 15-19 Settembre 2008 Status report of the LHCf experiment: preparation for data taking Oscar Adriani INFN Sezione di Firenze - Dipartimento di Fisica dell’Università degli Studi di Firenze

LHCf: location and detector layout Detector I Tungsten Scintillator Scintillating fibers Detector II Tungsten Scintillator Silicon mstrips INTERACTION POINT IP1 (ATLAS) 140 m 140 m Beam line Detectors should measure energy and position of g from p0 decays e.m. calorimeters with position sensitive layers Two independent detectors on both side of IP1 Redundancy Background rejection (especially beam-gas) 18 Settembre 2008 CSN1 – Pisa O. Adriani

LHCf location Detectors installed in the TAN region, 140 m away from the Interaction Point, in front of luminosity monitors Here the beam pipe splits in 2 separate tubes. Charged particle are swept away by magnets!!! We will cover up to y 18 Settembre 2008 CSN1 – Pisa O. Adriani

Detector #1 Impact point (h) Energy 2 towers 24 cm long stacked vertically with 5 mm gap Lower: 2 cm x 2 cm area Upper: 4 cm x 4 cm area 4 pairs of scintillating fiber layers for tracking purpose (6, 10, 32, 38 r.l.) Absorber 22 tungsten layers 7mm – 14 mm thick (W: X0 = 3.5mm, RM = 9mm) 16 scintillator layers (3 mm thick) Trigger and energy profile measurements Energy 18 Settembre 2008 CSN1 – Pisa O. Adriani

Detector # 2 Impact point (h) Energy We used LHC style electronics and readout Impact point (h) 2 towers 24 cm long stacked on their edges and offset from one another Lower: 2.5 cm x 2.5 cm Upper: 3.2 cm x 3.2 cm 4 pairs of silicon microstrip layers (6, 12, 30, 42 r.l.) for tracking purpose (X and Y directions) 16 scintillator layers (3 mm thick) Trigger and energy profile measurements Absorber 22 tungsten layers 7mm – 14 mm thick (2-4 r.l.) (W: X0 = 3.5mm, RM = 9mm) Energy 18 Settembre 2008 CSN1 – Pisa O. Adriani

Double ARM Detectors 290mm 90mm Arm#2 Detector Arm#1 Detector 18 Settembre 2008 CSN1 – Pisa O. Adriani

Installation Final installation was completed in January 2008 No major problems have been found Both Arm1 and Arm2 are working fine No additional noise is found in the detectors, despite 200 m long power lines and signal cables (for the scintillators) The only problem: quartz optical fiber for laser calibration (yet another fiber problem…..) The quartz fiber for N2 laser calibration was broken last year during installation The new fiber was installed in January … but…. Problems in the connectors installation…. After this….. Unfortunately we discovered the fiber was the wrong one!!!!!!!!!!!! New and final installation in the last week free for access (May) Now is finally OK! 18 Settembre 2008 CSN1 – Pisa O. Adriani

Detectors in place Installation performed in two phases: Pre-Installation (2007) Baking out of the beam pipe (200 °C) Final Installation (Jan 2008) LHCf Luminosity Monitor (BRAN) ATLAS ZDC 18 Settembre 2008 CSN1 – Pisa O. Adriani

Some problems of grounding have been solved…. 18 Settembre 2008 CSN1 – Pisa O. Adriani

18 Settembre 2008 CSN1 – Pisa O. Adriani

Counting room cables clean-up 18 Settembre 2008 CSN1 – Pisa O. Adriani

Front Counter 2 fixed Front Counters were installed in front of Arm1 and Arm2 They will not move with Arm1 and Arm2 They are segmented in 2 x and 2 y slices Very useful to check the beam quality and hence decide to move Arm1 and Arm2 in the operating position from the ‘garage’ position 18 Settembre 2008 CSN1 – Pisa O. Adriani

After the installation…. After the installation was completed, a lot of work on: DAQ New VME board to increase DAQ rate up to > 1 KHz Integration of all the subsystem (Using MIDAS frame) Analyzer to check the data quality and online monitor Slow control software to control and monitor: Power supplies Manipulator Temperature monitor LHC interface New NIM style board (CIBU) to send ‘PERMIT’ to LHC (KILL the beam in case of high rate) Handhshaking software signals (DIP standard) for Injection, Adjust and Beam Dump LHCf Physics information (beam position, rate, background etc.) 18 Settembre 2008 CSN1 – Pisa O. Adriani

An Update on the 2007 SPS Beam Test Test was very successful!!!! Energy calibration of the calorimeters Spatial resolution of the tracking systems Results were partially published on JINST: 2008 JINST 3 S08006 CERN : SPS T2 H4 August/September 2007 Incident Particles Proton　 150,350 GeV/c Electron 50, 100, 150, 200 GeV/c Muon 150 GeV/c Setup LHCf Detector Silicon Tracker Moving Table Trigger Scintillator 18 Settembre 2008 CSN1 – Pisa O. Adriani

Energy Resolution Monte Carlo Test Beam N Particles Distance from Edge Energy distribution is corrected for leakage MC predicts that the leakage is energy independent! 18 Settembre 2008 CSN1 – Pisa O. Adriani

Energy Resolution Energy resolution < 3% even 2 x 2 cm2 tower 2.5 x 2.5 cm2 tower Energy resolution < 3% even for the smallest tower! 18 Settembre 2008 CSN1 – Pisa O. Adriani

Simulation vs Data Simulation is very well understood! 150 GeV m Energy released in the 4° scintillation layer Simulation is very well understood! 100 GeV e- 18 Settembre 2008 CSN1 – Pisa O. Adriani

in the slot used for beam monitor p0 reconstruction g 350 GeV Proton beam Not in scale! g Carbon target (3 cm) in the slot used for beam monitor 9.15 m Arm1 >107 proton on target (special setting from the SPS people) Dedicated trigger on both towers of the calorimeter has been used Egamma=18GeV Shower Profile @ First SciFi Layer Calorimeters 20mm X 40mm Y Egamma=46GeV 18 Settembre 2008 CSN1 – Pisa O. Adriani

p0 mass reconstruction Dm ~ 8 MeV Dm/m ~ 6% Preliminary!!!! (MeV)  250 p0 events triggered (in a quite big background) and on disk Preliminary!!!! (MeV) Main problems: low photon energy (≥ 20 GeV) Direct protons in the towers Multi hits in the same tower Dm ~ 8 MeV Dm/m ~ 6% 18 Settembre 2008 CSN1 – Pisa O. Adriani

ARM1 Position resolution 200 GeV electrons sx=172 mm Number of event σx[mm] x-pos[mm] E[GeV] σy[mm] sy=159 mm Number of event y-pos[mm] E[GeV] 18 Settembre 2008 CSN1 – Pisa O. Adriani

ARM2 Position Resolution 200 GeV electrons sx=40 mm x-pos[mm] sy=64 mm y-pos[mm] Alignment has been taken into account 18 Settembre 2008 CSN1 – Pisa O. Adriani

ARM2-Silicon Energy Resolution 200 GeV electrons SPS beam test data DE/E ~ 12% Total energy measured in silicon (ADC) By looking only at the silicon energy measured, we have an energy resolution ~ 10%!!!!! We can use it as a check for the radiation damage of the scintillators 18 Settembre 2008 CSN1 – Pisa O. Adriani

Linearity in the Silicon Energy Correction for energy leakage is not applied At least in the 50-200 GeV energy range the silicon energy measurement is linear 18 Settembre 2008 CSN1 – Pisa O. Adriani

Preparation for data taking A ‘control room’ …. has been prepared since there was no space for us in the Atlas buildings …. 18 Settembre 2008 CSN1 – Pisa O. Adriani

But our Control Room is fully equipped! Furnitures Telephones Air conditioner Network Computers Printers …… And also with Japanese students!!!!! 18 Settembre 2008 CSN1 – Pisa O. Adriani

Dummy event 18 Settembre 2008 CSN1 – Pisa O. Adriani

Communications with LHC LHCf sends signals to LHC through the DIP system. Link have been tested and it works fine! Important for machine tuning! We are in strict contact with them. Experimental status (On/Off, Gain, etc.) Detector position (Garage/Operating, position in mm, etc.) Luminosity rate (Single and Double Arm) Front Counter rate (single Arm, double Arm coincidence) Small tower rate (single Arm) Big tower rate (single Arm) Double Arm coincidence rate (FC.AND.Towers in opposite sides) Horizontal and Vertical position of the Beam (every 10000 events or in the whole RUN) Injection Inhibit Handshaking signals (Injection, Adjust, Beam Dump) 18 Settembre 2008 CSN1 – Pisa O. Adriani

We are ready for data taking On September 10 we observed some signals on Front Counters, with Arm1 and Arm2 in garage position for safety reasons That day the Atlas BPTX signal was still not available (no info on the real bunches in the Atlas zone) On September 11 Atlas gave us the synchronized BPTX signals, and we could take Front Counter data by using this signal (still in garage position) We are measuring Beam-Gas from the Beam2 on Arm1 side 18 Settembre 2008 CSN1 – Pisa O. Adriani

18 Settembre 2008 CSN1 – Pisa O. Adriani

‘Analysis’ of Beam Gas events We got 116 FC triggers in 8.275.034 BPTX: Nt=116 2.109 protons/bunch Total # of protons: Np=1.7 x 1016 We try to estimate the gas density r from this rate: Nt=Np* L * s * r L=effective lenght ~ 100 m s=Cross section ~ 80 mbarn = 80 x 10-31 m2 We find: r = 8.5 x 1012 H/m3 = 4.2 x 1012 H2/m3 From the LHC Project Report #783: r = 1012 H2/m3 From the pressure measurement in April 2008: r ~ 1012 H2/m3 ~ CONSISTENT!!!!!!!!!!!!! 18 Settembre 2008 CSN1 – Pisa O. Adriani

While waiting for collisions…. Proton A short comment on new models: PICCO, EPOS Very big interest in LHCf data and in this physics field Drescher, Physical Review D77, 056003 (2008) p0 Neutron 18 Settembre 2008 CSN1 – Pisa O. Adriani

LHCf : Monte Carlo discrimination 106 generated LHC interactions  1 Minute exposure@1029 cm-2s-1 luminosity Discrimination between various models is feasible in a very short time Quantitative discrimination with the help of a properly defined c2 discriminating variable based on the spectrum shape (see TDR for details) 5% Energy resolution 18 Settembre 2008 CSN1 – Pisa O. Adriani

Conclusions A lot of work has been done in 2008 Installation completed Preparation for running completed First beam gas events acquired Will we get collisions today??? We are ready to send our info to LHC for beam tuning 18 Settembre 2008 CSN1 – Pisa O. Adriani

Spare slides

Radiation Damage Studies Scintillating fibers and scintillators Expected dose: 100 Gy/day at 1030 cm-2s-1 Few months @ 1030 cm-2s-1: 10 kGy 50% light output Continous monitor and calibration with Laser system!!! 30 kGy 18 Settembre 2008 CSN1 – Pisa O. Adriani

Estimate of the background beam-beam pipe  E γ(signal) > 200 GeV, OK background < 1% beam-gas  It depends on the beam condition background < 1% (under 10-10 Torr) beam halo-beam pipe  It has been newly estimated from the beam loss rate Background < 10% (conservative value) 18 Settembre 2008 CSN1 – Pisa O. Adriani

Effect of LHCf on BRAN measurement LUMI monitor (BRAN) inside TAN is beyond LHCf (replacing 4th copper bar) IP1 Cu Bar / ZDC LHCf LHCf Cu Bar / ZDC Lumi Lumi The effect of LHCf on BRAN measurements has been studied in the last months by simulation Reduction of shower particles at BRAN Position dependence on beam displacement (question from machine peoples: if we shift by 1 mm the real beam, does the center of the measured neutral energy shifts by 1 mm?) 18 Settembre 2008 CSN1 – Pisa O. Adriani

LHCf performances: p0 geometrical acceptance Arm #1 Arm #2 18 Settembre 2008 CSN1 – Pisa O. Adriani

LHCf performances: energy spectrum of p0 Typical energy resolution of g is 3 % at 1 TeV 18 Settembre 2008 CSN1 – Pisa O. Adriani

Transverse projection in TAN slot ARM1: Maximization of the acceptance for vertical beam displacement (crossing angle>0) ARM2: Maximization of the acceptance in R (distance from beam center) 18 Settembre 2008 CSN1 – Pisa O. Adriani

LHCf: model dependence of neutron energy distribution Original n energy 30% energy resolution 18 Settembre 2008 CSN1 – Pisa O. Adriani