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GEM Tracker Luminometer at Dafne Upgrade

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  1. GEM Tracker Luminometer at Dafne Upgrade GEM principia Detector construction Test beam at BTF The background monitor Analysis on bhabha Next step G. Corradi, F. Iacoangeli, M.Pistilli, G.Sensolini, D.Tagnani & FM

  2. Gas Electron Multiplier 31x31 cm2 A Gas Electron Multiplier (F.Sauli, NIM A386 531 1997) is made by 50 m thick kapton foil, copper clad on each side and perforated by an high surface-density of bi-conical channels; 70 µm 140 µm 50 µm

  3. Triple GEM geometries Gain ~20 ~20 ~20 ~8000 Pads of 6 x (22-32) mm2

  4. LUMI GEM Assembling Seven detectors built pads induction gap GEM 3 GEM 2 GEM 1 Cathode Final luminometers with Carioca FEE

  5. Design for Bhabha Luminometer 4 detectors with 32 channels each with a total diameter of 20 cm are designed and ready for the assembling phase. PAD PCB places for 2 FEE cards Back side

  6. New 16 channels card The card has been designed and realized (Gianni Corradi, Diego Tagnani) Total dimension : 3x6 cm2 Few cards already mounted Channel density of 1 ch/cm2 Sensitivity of 2-3 fC; LVDS output (25 ns); Radhard; Extremely modular and usable for other GEM applications (big surface with pads readout) two possibility : out in out PCB

  7. Test beam at BTF The GEM detectors were calibrated at BTF on December Efficiency (%) Triple GEM voltage

  8. 5 mm GEM luminometer mounted on IP The detectors were displaced 5 mmtowards the machine center Electron monitor Positorn Monitor 3 1 4 3 1 4 2 G.Sensolini 2

  9. DAQ Scheme Programmable FPGA (F. Iacoangeli) V 1 4 9 5 LVDS LVDS L V D S T D C 3 4 1 128 ch OFFLINE ANALYSIS 2 L V D S E C L OR AND ECL K L O E D A Q K L O E T D C S C A L E R ONLINE BACKGROUND MONITOR

  10. Background monitor 28 KHz Only Electron Beam Electron monitor 80 mA Positron Monitor 48 KHz

  11. x 4 1 Online Coincidence rate 500 ms 60 sec Gain at 1130 V Where are the Bhabha ?

  12. Multiplicity on luminometer lumi 1 lumi 2 lumi 3 lumi 4

  13. Bhabha time distribution lumi 1 vs lumi4 lumi 2 vs lumi3 Time (ns) Time (ns)

  14. Bhabha theta and phi distribution 2.0 p 1.5 p 1.0 p 0.5 p 0 0 0.5 p 1 p 1.5p 2p

  15. Bhabha distribution Phi distribution Theta distribution Calo PM OFF Calo PM OFF

  16. Efficiency vs HV settings 1200 1260 1280 1300 1220 1260 1280 1320

  17. Bhabha events Bhabha seems are not collinear !

  18. What we need for the future • Measure the efficiency of luminometer (HV scan) • Measure the efficiency vs FEE thresolds • Asap the mezzanine arrive try to move back to KLOE DAQ

  19. Bremstrhalung Monitor with GEM

  20. 3GEM monitor on DaFne On April 2007 the 3GEM chamber has been put at zero degree on DaFne for photon detection coming from the Finuda interaction region e+ e- e+ e-g e - 3GEM e + lead beamstrahlung g

  21. Online Monitor Photon beam spot Number of hits vs time Finuda luminosity vs time 24 mm 24 mm Masked Channels Rate of 1-2 MHz per cm2

  22. Analysis: GEMlumi vs Finuda Lumi Comparisons between the two luminosity slumi (1030 cm-2 s-1) GEMlumi Finuda Lumi slumi = 5.8 x 1030 Finuda lumi =0 Dlumi (1030) time (days of May)

  23. Analysis : photon beam profile Data taking of 2007-05-09 x position (mm) x position (mm) y position (mm) y position (mm)

  24. Analysis : photon beam position The monitor was active for all the last period of DAFNE Runs This is the photon beam position during month of May x position (mm) Detector always ON also during beam lost phase y position (mm) time (days of May)