1 / 24

Study of ECAL resolution Alexandr Kozlinskiy Budker Institute of Nuclear Physics, Novosibirsk

Study of ECAL resolution Alexandr Kozlinskiy Budker Institute of Nuclear Physics, Novosibirsk. Outline. Motivation Tools "Beam test conditions". Energy resolution. MC corrections Results Next step. 1. Motivation Resolution on beam test. 11th Vienna Conference on Instrumentation

mai
Télécharger la présentation

Study of ECAL resolution Alexandr Kozlinskiy Budker Institute of Nuclear Physics, Novosibirsk

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Study of ECAL resolution Alexandr Kozlinskiy Budker Institute of Nuclear Physics, Novosibirsk

  2. Outline • Motivation • Tools • "Beam test conditions". • Energy resolution. • MC corrections • Results • Next step Alexandr Kozlinskiy

  3. 1. Motivation Resolution on beam test 11th Vienna Conference on Instrumentation "Calorimeters for collider experiments" ( Andrey GOLUTVIN (ITEP Moscow) ) • Resolution on beam test gives: • MC of one module gives the same results. Test beam results Alexandr Kozlinskiy

  4. 1. Motivation Energy resolution DC04 Olivier Deschamps results for DC04 SPD hit MC of PGUN photons in DC04: no SPD hit no SPD, no PS σE/E (%) 1/√E (GeV1/2) Alexandr Kozlinskiy

  5. 1. Motivation Resolution parameters are important for understanding pools and fits. • Why resolution become worse? • Experts say that SPD and PS • should not worsen resolution. • Are there bugs in MC? • Or is it dead material before ECAL? Alexandr Kozlinskiy

  6. 1. Motivation • We can try to recreate beam test conditions. • There are two ways to do it: • 1. remove all material before ECAL in MC. But it is to hard to debug. • 2. place particle just before ECAL. In this case however we have to take into account time of particle birth. • Of course we will not have the same conditions as in the beam test: • there are many corrections in MC - noise, gain errors etc. Alexandr Kozlinskiy

  7. 2. Tools. Standard particle gun was changed to make it possible to generate particle at any point in the detector with respect to time needed for this particle to fly from center of interaction to the initial vertex: • Gauss v25r7 • Boole v12r10 • Brunel v30r14 • DaVinci v17r8 ECAL particle direction initial vertex time correction center of interaction z Alexandr Kozlinskiy

  8. 3. "Beam test conditions" Vertex: 381.5 mm, 383.2 mm, 12468 mm, +41.7 ns ( before ECAL inner zone ) • energy resolution • space resolution Alexandr Kozlinskiy

  9. Energy resolution • Relative energy difference distributions for different energies of photon: • 13 points from 0.4 to 8 GeV of transverse energy. • So there are 13 histograms with 1000 events in each histogram. 166 GeV 185 GeV Along x-axis: 92.3 GeV 55.4 GeV Reconstructed energy is about 5% less then MC energy of photon. Alexandr Kozlinskiy

  10. Space resolution Angle difference is multiplied by 12500 mm ( distance to ECAL from center of interaction ) to make mm units (space resolution). The same 13 samples of events with different energies were used. 166 GeV 185 GeV Along x-axis: 92.3 GeV 55.4 GeV Space resolution along Y axis of detector is about 1.5 mm. Alexandr Kozlinskiy

  11. Energy and Space resolution • We have many energy and space distributions for different energies of photon. • We can use 2 different functions to fit energy resolution: • (with noise term) and (without noise term) 1. 2. Fits with functions 1 and 2 give very different results. Alexandr Kozlinskiy

  12. Energy and Space resolution Here we see that fit with noise term is better than without one. Energy resolution is in good agreement with beam test. The only difference is noise term which can be described by corrections in Boole. 5 % difference from MC photon energy Alexandr Kozlinskiy

  13. 4. Energy resolution dependence from vertex z-position Here we see dependency of parameters A, B and C in from vertex z-position. Red points: C = 0 MeV ( fit without noise - function number 2 ) There is visible difference for red and black points which shows that A and C parameters influence each other. There should be no dependence of noise term from vertex z-position. So we fix it on 350 MeV. 350 MeV Alexandr Kozlinskiy

  14. Energy resolution dependence from vertex z-position With fixed noise parameter: C = 350 MeV 12 % 1.0 % C = 350 MeV, B = 1.0 % B parameter is very close to 1.0 %. We can try to fit energy resolution with fixed B and C parameters. Alexandr Kozlinskiy

  15. 5. MC corrections Gauss: [GaussCalo::EcalSensDet algorithm v8r4] 3) local nonuniformity LHCb ECAL uniformity of response no contribution ( time shifting of vertex ) 11th Vienna Conference on Instrumentation "Calorimeters for collider experiments" ( Andrey GOLUTVIN (ITEP Moscow) ) Boole: [CaloDigit::CaloDigitAlg algorithm v2r2] 1) gain errors - 1 % 2) noise - about 1.5 channels Alexandr Kozlinskiy

  16. Resolution dependence from gain errors Resolution without gain errors correction in Boole. 1.0 % 0.6 % With removing of gain errors B term fall from 1.0 % to 0.6 %. 350 MeV Fixing noise term on 350 MeV. Alexandr Kozlinskiy

  17. Resolution dependence from gain errors C = 350 MeV 0.6 % C = 350 MeV, B = 0.6 % Fixing B and C term on 0.6 % and 350 MeV respectively. Alexandr Kozlinskiy

  18. Resolution dependence from noise • Noise consist of 2 terms: • coherent noise - 0.3 adc • incoherent noise - 1.2 adc Noise has fall to 200 MeV: it is the value of beam test Without noise C term fall to 200 MeV. We can say that 1.5 adc = 150 MeV. 200 MeV To compare resolution dependency to normal mode, let's fix C term on 200 MeV Alexandr Kozlinskiy

  19. Resolution dependence from noise C = 200 MeV 1.0 % C = 200 MeV, B = 1.0 % Fixing C term on 200 MeV and B term on 1.0 %. Alexandr Kozlinskiy

  20. Resolution dependence from nonuniformity Local nonuniformity doesn't give any visible changes in parameters on this stage. 350 MeV Let's fix C parameter as in normal mode. Alexandr Kozlinskiy

  21. Resolution dependence from nonuniformity C = 350 MeV 1.0 % C = 350 MeV, B = 1.0 % And fix B parameter on 1.0 %. Alexandr Kozlinskiy

  22. Different modes with fixed B and C terms no local nonuniformity C = 350 MeV, B = 1.0 % normal mode C = 350 MeV, B = 1.0 % 11.2 % 10.8 % Normal mode and modes without noise and gain errors almost identical. While mode without local nonuformity has slight better resolution before ECAL. no noise C = 350 MeV, B = 0.6 % no gain errors C = 200 MeV, B = 1.0 % Alexandr Kozlinskiy

  23. 6. Results Resolution for inner ECAL area: Energy resolution: Space resolution: 1. We have the same resolution as in Beam Test when vertex is placed just before ECAL. 2. With full MC - the resolution is the same as before. 3. The main conclusion from plots on previous slide is that corrections in MC are right and main source of resolution worsening is dead material before ECAL. Alexandr Kozlinskiy

  24. 7. Next step Irina's effect. There will be new correction to the adc value for hits which will be added soon (Irina's effect). This effect has probability about 1 % and value about 15-20 adc. probability: 1 % adc Alexandr Kozlinskiy

More Related