Introduction of my work AYAKO HIEI (AYA) Hiroshima Univ 2008/5/30 me

12 Motivation : ALICE & PHOS PHOton Spectrometer :is a electromagnetic calorimeter :consist of 5 module. 1 module consist of 56×64 PWO crystal … … 2008/5/30AYA / Introduction of my thesis work 2 We have to calibrate each crystal ! (56×64×5=17920) We have to calibrate each crystal ! (56×64×5=17920) Measurement feasible region:5-80MeV energy :3% We can operate PHOS By remote control without being influenced by a magnetic field.

12 How to calibrate energy In General use the incident particle of known behavior to a crystal 2008/5/30AYA / Introduction of my thesis work 3 For Example  Test Beam (Energy)  LED (signal level or fluctuation)  Inclination of energy distribution  MIP,Minimum Ionization Particle(Energy) ※ e.g. cosmic ray  Particle by collision (e.g. Invariant mass) etc… π0 invariant mass peak → γ + γ (98%) ※ Short life time π0 θ M γγ E γ1 E γ2 134MeV count Reconstructed invariant mass[MeV]

12 Energy calibration using pi0 mass peak 2008/5/30AYA / Introduction of my thesis work 4 π0 θ M γγ E γ1 E γ2 BAD GOOD π0 θ M γγ E γ1 E γ2 GOOD 134MeV count Invariant mass[MeV] 110MeV One of the two is fixed. Dead channel?? mis calibration?? For exsampe

12 In order to make this method establish It is necessary to: – Investigate whether the peak positions are in agreement or not, and then the statistical error. (using simulation) – Investigate how correct can we calibrate using only γ event on simulation, and using only pi0 event. and using collision event. etc 2008/5/30AYA / Introduction of my thesis work 5 NOW I try

12 Simulated collision 2008/5/30AYA / Introduction of my thesis work 6 pp ONLY PHOS pp collision √S=14TeV Event generator : PYTHIA Event Bias : Minimum Bias Number of Event : 4M Noise with a Gaussian with the RMS=4MeV Assumed a perfect calibration for each crystal noise →I have to apply some “cut”.

12 Reconstructed pi0 mass histogram : NO CUT 2008/5/30AYA / Introduction of my thesis work 7 What is this structure?

12 The structure consists of noise mainly. 2008/5/30AYA / Introduction of my thesis work 8 (1) (2) (3) (4) (5) (6) Noise with a Gaussian with RMS = 4MeV

12 Reconstructed pi0 mass histogram : apply CUT 2008/5/30AYA / Introduction of my thesis work 9 I apply  pT>1GeV/c  α< ±941 pi0 Statistics are insufficient. for investigating the mass depending on one crystal and SO …

12 The crystals are grouped in 8×7 2008/5/30AYA / Introduction of my thesis work ± [GeV/c 2 ] ± [GeV/c 2 ] The peak position are in agreement with each other within the statistical error Of 1~2%,with the perfect calibration BUT!

12 NOW I investigate the following group 2008/5/30AYA / Introduction of my thesis work 11 module x y ※ ALICE Coordinate system 0 54 crystal number ± [GeV/c 2 ] ± [GeV/c 2 ] Maybe a difference comes out most. because of Influence of a shower leak or clustering I want to see! (I have just try it now)

12 There are many things done still more It is necessary to: – Investigate whether the peak positions are in agreement or not, and then the statistical error. (using simulation) – Investigate how correct can we calibrate using only γ event on simulation, and using only pi0 event. and using collision event. etc 2008/5/30AYA / Introduction of my thesis work 12 NOW I try

Köszönöm for LISTENING 2008/5/30AYA / Introduction of my thesis work

12 BACK UP : Trigger for cosmic ray 2008/5/30AYA / Introduction of my thesis work 14 ALICE COsmic-Ray Detector (ACORD)

12 BACK UP : component E E’ DAQ Data acquisition System Primary Detecting element 2008/5/30 15 AYA / Introduction of my thesis work

12 BACK UP : signal flow Signal Sampling count Number of sample : 70 Sampling frequency : 10MHz 2008/5/30 16 AYA / Introduction of my thesis work 2 Shaper!!!

12 BACK UP 2008/5/30AYA / Introduction of my thesis work 17

12 BACK UP : shower shape 2008/5/30 18 AYA / Introduction of my thesis work 1 GeV electron By Chuman thesis electron cosmic ray hadronic showerpunch through μ