Preliminary estimate of performances using a 2- telescope system CTA meeting E. Carmona on behalf of the MAGIC collaboration Berlin, 5 May 2006

E. Carmona, Berlin 5 May 2006 CTA Meeting 2 Objective Estimate performances of a next generation CTA, optimized for low energy  ray showersEstimate performances of a next generation CTA, optimized for low energy  ray showers Assuming current technology, but with:Assuming current technology, but with:  Large light collection area (Ø 23 m)  High QE detectors (Si PMs) Simulate a 2 telescope system. Later, scale the results by the number of pairsSimulate a 2 telescope system. Later, scale the results by the number of pairs Done by using MAGIC-II Monte-Carlo data and analysis toolsDone by using MAGIC-II Monte-Carlo data and analysis tools  DATA: same reflector files used for MAGIC II studies

E. Carmona, Berlin 5 May 2006 CTA Meeting 3 MAGIC II Second Ø17 m telescope close to MAGIC I (~85 m)Second Ø17 m telescope close to MAGIC I (~85 m) MC study showed a factor ~2 improvement in sensitivity when going from 1 to 2 telescopeMC study showed a factor ~2 improvement in sensitivity when going from 1 to 2 telescope MAGIC-I MAGIC-II Distance between telescopes not criticalDistance between telescopes not critical

E. Carmona, Berlin 5 May 2006 CTA Meeting 4 Parameters of the simulation Simulation parameters:Simulation parameters:  Ø mirror = 23 m (estimated from 17 m)  f/D = 1 (FIXED)  Improved Reflectivity: 85% - 95%  Camera FoV up to 4.7º  Camera with different number of pixels  Camera pixels: SiPM, 50% QE, 10% gain fluctuations  3NN trigger  FADC 2 Gs/s  Distance between telescopes: 90 m (FIXED)  Events analysed only in stereo mode Aperture (A mirror ×Ref×QE) ~168 m 2 – MAGIC I ~26 m 2Aperture (A mirror ×Ref×QE) ~168 m 2 – MAGIC I ~26 m 2

E. Carmona, Berlin 5 May 2006 CTA Meeting 5 Simulation and analysis chain  and proton showers produced with Corsika  and proton showers produced with Corsika (v ) Photons on ground reflected with Reflector (atmospheric absorption) program: Reflector filesPhotons on ground reflected with Reflector (atmospheric absorption) program: Reflector files Camera simulation:Camera simulation:  New pixel response (SiPM)  Different number of pixels CalibrationCalibration Hillas parameters from camera outputHillas parameters from camera output  / hadron separation using Random Forest  / hadron separation using Random Forest MAGIC II CTA

E. Carmona, Berlin 5 May 2006 CTA Meeting 6 MC events  From 10 GeV to 10 TeV — 2×10 6 gammas, 20 files  From 100 GeV to 10 TeV — ~1.4×10 7 protons, 1411 files  Low energy proton production, 50 GeV – 100 GeV — ~3.5×10 7 protons, 3450 files  Very low energy proton production, 30 GeV – 50 GeV — ~1×10 7 protons, 1014 files Gammas Protons Estimate of other backgrounds added later:  50% proton rate increased (accounts for other hadrons)  Rough estimate of e flux (extrapolated from  results)

E. Carmona, Berlin 5 May 2006 CTA Meeting 7 Camera simulation Hexagonal camera and pixelsHexagonal camera and pixels f/D = 1f/D = 1 Example:Example:  3571 pixels, 0.067º  4.65º FoV  3.30º Trigger Different cameras have been simulated:Different cameras have been simulated:  3571 Pixels, 0.067º (4.65º FoV, 3.3º trigger)  3571 Pixels, optimistic optics  1657 pixels, 0.067º (3.3º FoV, 3.3º trigger)  1519 Pixels, 0.10º (4.54º FoV, 3.2º trigger)  721 Pixels, 0.10º (3.2º FoV, 3.2º trigger)

E. Carmona, Berlin 5 May 2006 CTA Meeting 8  images NO NOISE

E. Carmona, Berlin 5 May 2006 CTA Meeting 9  images

E. Carmona, Berlin 5 May 2006 CTA Meeting 10 Energy threshold High photon collection efficiency allows to go down in energyHigh photon collection efficiency allows to go down in energy Number of events after computing Hillas parameters No /h separation

E. Carmona, Berlin 5 May 2006 CTA Meeting 11  /h separation Is done with Random ForestIs done with Random Forest Mean scaled width and length are useful parameters for separationMean scaled width and length are useful parameters for separation

E. Carmona, Berlin 5 May 2006 CTA Meeting 12  /h separation /h separation improves with size /h separation improves with size 3571 pixels 50<size< pixels 150<size< pixles 300<size< pixels 600<size< pixels 1000<size<2000

E. Carmona, Berlin 5 May 2006 CTA Meeting 13 Effective area for gammas 3571 pixels, 4.7º 1519 pixels, 4.7º 1657 pixels, 3.3º 721 pixels, 3.3º

E. Carmona, Berlin 5 May 2006 CTA Meeting 14 Angular Resolution (  containing 50%  in  2 plot ) 3571 pixels, 4.7º 1519 pixels, 4.7º 1657 pixels, 3.3º 721 pixels, 3.3º

E. Carmona, Berlin 5 May 2006 CTA Meeting 15 Flux sensitivity 3571 pixels, 4.7º 1519 pixels, 4.7º 1657 pixels, 3.3º 721 pixels, 3.3º

E. Carmona, Berlin 5 May 2006 CTA Meeting 16 Improved spread function Optimistic optical PSF of photonsOptimistic optical PSF of photons Differences only important for low EDifferences only important for low E

E. Carmona, Berlin 5 May 2006 CTA Meeting 17 Electron estimate Electron flux estimated from  showers from 10 to 100 GeV. Assuming:Electron flux estimated from  showers from 10 to 100 GeV. Assuming:  Electron flux: 1.2×10 -3 E -1 (1 + (E/5 GeV) 2.3 ) -1 cm -2 sr -1 s -1 GeV -1  Hadronness of electrons equal to s  Flat distribution in  2 in  2 Effect is small,Effect is small, because of  2 cut

E. Carmona, Berlin 5 May 2006 CTA Meeting 18 CT array flux limits

E. Carmona, Berlin 5 May 2006 CTA Meeting 19 Conclusions 2-telescope with high light collection efficiency (mirror area and QE) has been studied2-telescope with high light collection efficiency (mirror area and QE) has been studied Simple analysis without any improvement can lower the energy threshold of a CT to ~10 GeV (lower?)Simple analysis without any improvement can lower the energy threshold of a CT to ~10 GeV (lower?) Pixel size has a small effect at low energiesPixel size has a small effect at low energies Smaller pixels allow an improvement in angular resolution and flux sensitivitySmaller pixels allow an improvement in angular resolution and flux sensitivity Improving psf of photons before camera (better optics) might be important to improve performance at low energiesImproving psf of photons before camera (better optics) might be important to improve performance at low energies Electron flux not a problem, efficiently reduced with  2Electron flux not a problem, efficiently reduced with  2

E. Carmona, Berlin 5 May 2006 CTA Meeting 20 To be done Study energy resolutionStudy energy resolution Use time in the analysisUse time in the analysis Use 3 or more telescopes in coincidenceUse 3 or more telescopes in coincidence Change geometry of the arrayChange geometry of the array

E. Carmona, Berlin 5 May 2006 CTA Meeting 22 SiPMs Flat 50% QE between 300 – 600 nmFlat 50% QE between 300 – 600 nm Gain fluctuations of 10% introduce in cameraGain fluctuations of 10% introduce in camera NSB factor for SiPMNSB factor for SiPM 2.4 (w.r.t. EMI coated)

E. Carmona, Berlin 5 May 2006 CTA Meeting 23 Proton images

E. Carmona, Berlin 5 May 2006 CTA Meeting 24 Camera Output Full simulation of camera performed. Output is data in the RAW data format of MAGICFull simulation of camera performed. Output is data in the RAW data format of MAGIC Size of the raw output files and simulation time is a problem:Size of the raw output files and simulation time is a problem:  Gammas → 21.8 Gb, ~25 hours for 10 5 showers  Protons → 540 Mb, ~1 hours for 10 4 showers  Protons low E → 96 Mb, ~20 minutes for 10 4 showers  Protons very low E → 210 Mb, ~100 minutes for 10 5 showers The whole simulation-analysis process has been automatizedThe whole simulation-analysis process has been automatized Only a small part of the data is finally storedOnly a small part of the data is finally stored

E. Carmona, Berlin 5 May 2006 CTA Meeting 25  /h separation