1 / 28

Timing Counter status @ Sept. 2004

Timing Counter status @ Sept. 2004. Timing Counter Activities. Timing resolution: 100 ps FWHM have been achieved. PM’s characterised in the COBRA magnet for gain and timing. Full characterisation of single TC’s counter is started Final design and integration with DC is started

samara
Download Presentation

Timing Counter status @ Sept. 2004

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. Timing Counterstatus @ Sept. 2004 Giorgio Cecchet

  2. Timing Counter Activities • Timing resolution: 100 ps FWHM havebeen achieved. • PM’s characterised in the COBRA magnet for gain and timing. • Full characterisation of single TC’s counter is started • Final design and integration with DC is started • Ф-detector : APD directly from Hamamatsu Giorgio Cecchet

  3. Low Thr. High Thr. coinc Delay Scintillator 248 ps FWHM Light guide Timing resolution measurements • First test(PSI-E5)- may 03: -BC404 (1X5x80 cm3) – light guides and 1”1/2 and 2” Hamamatsu Fine Mesh PMs -passive beam collimation (6mm diameter) -5 cm positron path length. -Analogic electronics - Double Threshold Discriminator-MCA  2.35x s[(tL- tR)]/2= 124 ps FWHM PM (tL- tR) Giorgio Cecchet

  4. APD Scint. Fiber beam APD Timing resolution measurements • Last test (LNF-Frascati-Beam Test Facility) January 04: Energy Range 25-800 MeV e- 25-550 MeV e+ Max. Repetition Rate 50 Hz Pulse Duration 1-10 ns Current/pulse 1 to 1010 particles (Allowed Current 103 particles/second) Beam spot : sx=2mm sy=4mm (in the focus) • Further geometrical selection of 5mmx5mm spot by two scintillating fibers with APD read-out. Time spread due to the spot size ~25ps. • Coincidence with “APD cross” and the LINAC trigger allow to reject most of the bck. Events. Spot Size Time spread ~25ps Giorgio Cecchet

  5. Timing resolution measurements • 1,2,3 electron events are resolved in the charge spectrum • (tL- tR) is selected in the 1e peak Our Best Results : 2.35x s[(tL- tR)]/2= 1042ps FWHM 2e 1e 3e Giorgio Cecchet

  6. Characterisation in MagField Giorgio Cecchet

  7. Giorgio Cecchet

  8. Giorgio Cecchet

  9. Gain vs Rate Zero field 1.05 T 27.5º The Gain vs Rate at 1500 V in zero field is fully recovered at 1.05 T and 27.5º at 2100 V. Unallowable increase of biasing voltage are needed at 0º. Giorgio Cecchet

  10. Gain Vs Bias at several angles +10º Max gain curve in magn. field Same gain +10º Giorgio Cecchet

  11. RMS timing resolution vs p.e. attenuator 60ps pulsed blue Laser 100um Fiber Laser beam illuminates the whole photocatode PM Giorgio Cecchet

  12. Giorgio Cecchet

  13. ☺Increase Positron Path-Length ~ 5 cm ☺Improve Geom. Matching Scint.-PMT ☺Tilt the PM @ ~30º respect Magn. Field →Rotated Scint. Slab improves response uniformity and timing performance due to coincidences. Giorgio Cecchet

  14. From COBRA center 105 cm 25 cm 8.5º 30º 30º 10º B B TC key features PM active diameter Scintillator Cross Section 39x39 mm 70º PM section 1.05 T 0.75 T Giorgio Cecchet

  15. 50x39 mm • Conclusions: • 2” PMs allow to obtain the target resolution • At first order, the resolution is limited by the number of photoelectrons (light output from scintillator, quantum efficiency of PM, coupling scintillator-PM[2”], which has 39 mm dia. active area) • At second order, the slew rate could be used to improve the resolution in small signal regime: we have demonstrated that amplification recovers the timing resolution. • 2” PMs can supply 100uA -maximum- current ( 10uA for 1.5” PMs) • 2” PMs lifetime correspond to 2.3 years at the event rate of 50kHz @ gain of 6x105. An increase of a factor 2 can be easily obtained. • To be done: • First systematic tests of single element of TC started in the run (May, 31 – June, 12) and will continue in the Frascati BTF • Finalize the design of TC and integration with DC 39x39 mm Giorgio Cecchet

  16. Giorgio Cecchet

  17. Single Counter Response Study Giorgio Cecchet

  18. BC408 Very Preliminary Time Resolution FWHM (ps) BC404 Position (mm) Single Counter Response Study • 39x39 slab in rotated configuration simulating a positron trajectory @ 40.5° along z and 70°in radial plane Giorgio Cecchet

  19. Mechanical design Giorgio Cecchet

  20. From COBRA center 105 cm 25 cm 8.5º 30º 30º 10º B B Giorgio Cecchet

  21. Giorgio Cecchet

  22. 3D view of TC Giorgio Cecchet

  23. Transverse Timing Counter Giorgio Cecchet

  24. Scint. Fibers 5 x 10 mm APD Curved detector (triggering) • The design of the curved detectors has been modified in order to match the budget limits for procurement of virgin APD form Hamamatsu (159 Euro/each). • ~ 80 scintillating fibers and 160 APD per each TC. • Procurement preliminary procedure started Giorgio Cecchet

  25. 2002 2003 2004 2005 PMT Evaluation Beam Test PMT procur. APD Evaluation APD procur. APD test Design Procur & Manuf. Assembly PMT Evaluation Beam Test COBRA Test PMT procur. New APDs APD Evaluation APD procur. APD test APD procur. Design Procur & Manuf. Mechanical matching BG test Design Manufactoring Assembly Test Milestone Timing Counter Schedule Full installation Giorgio Cecchet

  26. - detector (triggering) • We found good APDs with high S/N ratio that we tested at PSI and LNF (Frascati) e- beam Pure e-beam Giorgio Cecchet

  27. - detector (triggering) • But, only about 10% of the selected APDs are good enough • Huge spread in dynamic parameters not predictable from static parameters [left figure] • The CMS selection and conditioning of the first batch of APDs is not applicable to MEG (we are working at few Volts from Vbkd – high gain- and we are interested to high slew rate and high S/N for timing purpose) • For comparison new APDs from Hamamatsu have similar response[right figure] • More work is needed to better understand the correlation between static and dynamic parameters of CMS APDs. from CMS selection From Hamamatsu Giorgio Cecchet

  28. Copper block APD Splitters Pulsed Laser Peltier Cell 1/1000 attenuator Integrating Calibrated Photometer Fast Photodiode Photomultiplier Status of test and procurements of APD APD test bench in Genoa About 10% can be accepted Giorgio Cecchet

More Related