M. Bonesini MICE TOF stations INFN Milanoplanning construction & M. Bonesini - 22/10/05 RAL 1
Outline q Introduction q Present design for TOF 0 q PMTs studies q Current problems q Funding & timescale q Present design for TOF 1/TOF 2 q PMTs studies q Open questions (TOF 0/TOF 1/TOF 2) q Conclusions M. Bonesini - 22/10/05 RAL 2
Aims of TOF stations • TOF 0 experiment trigger • TOF 0/TOF 1 PID on incoming muons • TOF 1/TOF 2 PID on particle traversing the cooling channel • TOF 1/TOF 2 contribute (t) to emittance measurement (st~60 ps has been questioned by INFN referees for TOF 2) • Detector requirements: o Single detector resolution s~60 ps o High rate capability o Sustain nearby not-uniform B fringe fields M. Bonesini - 22/10/05 RAL 3
ISIS Beam TRD SEPT 04 Layout Iron Shield Proton Absorber TOF 0 TOF 1 Diffuser Ckov 1 M. Bonesini - 22/10/05 RAL Iron Shield TOF 2 Ckov 2 Cal 4
r orim ete kov ren Cal Che 0 To. F …MICE Tof 2 Tracking Spectrometers Tof 1 Coupling Coils Focus Coils Beam Diffuser Matching Coils Liquid Hydrogen Absorbers M. Bonesini - 22/10/05 RAL RF Cavities 5
TOF 0 design is presently based on SEP 04 beamline (mods may be foreseen for AUG 05) • Particle rates was around 2. 4 -2. 8 MHz for TOF 0, it seems that new beamline AUG 05 will reduce it to ~ 1. 6 MHz -> better if beam profile will not shrink in AUG 05 • TOF 0 in the fringe field of quadrupoles for TOF 0 B << 50 gauss (mail from Kevin). Conventional fast PMTs Hamamatsu R 4998 with booster or active divider+mu-metal shielding M. Bonesini - 22/10/05 RAL 6
Summary of Rates (Sept 04 from Tom Roberts) Description LAHET Geant 4 MARS TOF 0 TOF 1 Tracker 1 2355 462 422 2693 529 482 2834 557 507 Tracker 2 TOF 2 Good μ+ 284 281 277 324 321 316 342 338 333 Values are events per millisecond of Good Target; absorbers empty, no RF. Good μ+ = TOF 0 & TOF 1 & Tracker 2 & TOF 1(μ+) & TOF 2(μ+) Major changes from before: 2 in. total thickness of TOF 0 and TOF 1 ~20% reduction in Good μ+ ~50% larger target acceptance ~10% increase in TOF 0 singles, ~1% in Good μ+. M. Bonesini - 22/10/05 RAL 7
Rates (Singles per ms) target insertion reduced to get 600 good mu+/sec (AUG 05) LAHET Geant 4 MARS Average TOF 0 1722 1762 1508 1664 TOF 1 813 832 712 786 Tracker 1 771 790 675 745 Tracker 2 629 644 551 608 TOF 2 627 641 549 606 Good μ+ 621 635 544 600 (Ev/sec) M. Bonesini - 22/10/05 RAL 8
Some simulation studies: TOF 0 TRD Size 480 x 480 SEPT 04 M. Bonesini - 22/10/05 RAL 9
TOF 0 X/Y singles projection SEP 04 beamline (TRD) has fixed counter size to L=48 cm, W= 4 cm (T= 1”) M. Bonesini - 22/10/05 RAL 10
TOF 0 AUG 05 beamline: news from 21/10/05 from T. Roberts “Maybe” (? ) we may think to reduce detector size L, W We cannot go much lower for W : PMT assembly outer size is ~ 3. 2 cm, only realistic possibility is L M. Bonesini - 22/10/05 RAL We keep design as it is now for the present time 11
Scintillator counter layout • based on present beamline EJ 230 BC 420 BC 404 Light output 64 % 64% 68% max 391 nm 408 nm Risetime 0. 5 ns 0. 7 ns Decay time 1. 5 ns 1. 8 ns Pukse FWHM 1. 3 ns 2. 2 ns Att length - 140 cm assumptions for all TOF stations L=480 mm, T=1”, W=40 mm for TOF 0, 600 mm for TOF 1/2. Choice between BC 404/420 scintillator or ELJEN Technology 230 (~same quality) • To be revised with AUG 05 beamline design: but soon, orders must be placed now for scintillator. Mainly I must fix L, W for TOF 0 140 cm M. Bonesini - 22/10/05 RAL Seems a better choice 12
Mechanics for TOF 0 View of X/Y plane: 12 vertical counters , 12 horizontal counters M. Bonesini - 22/10/05 RAL 13
TOF 0 support structure No major changes foreseen up now M. Bonesini - 22/10/05 RAL 14
Considerations for TOF 0 PMT choice 1. Rate capability (up to some MHz) 2. Good timing properties (TTS) 3. Sustain magnetic field (we now assume <<50 gauss for TOF 0) M. Bonesini - 22/10/05 RAL 15
Conventional PMT test setup Laser source to simulate MIP signal (about 300 p. e. ) : • fast AVTECH pulser AVO-9 A-C (risetime 200 ps, width 0. 4 -4 ns, repetition rate 1 KHz-1 MHz) with NDHV 310 APC Nichia violet laser diode(~400 nm, 60 m. W) NEW!! • fast PLP-10 laser on loan from Hamamatsu Italia Laser sync out triggers VME based acquisition (TDC + QADC) // MCA SILENA system Home made solenoid test magnet (B up to 50 gauss, d~20 cm, L~50 cm) see later for details M. Bonesini - 22/10/05 RAL 16
Rate capabilities of PMTs To have a linear signal the mean average anode current (100 A for R 4998 ) must not be exceeded -> damage to dynodes. . . shorter PMT lifetime This gives a theoretical rate capability of: 267 KHZ with R 4998 BUT !!! Divider can be modified for R 4998 (going up to 1. 67 MHZ) with booster or active divider M. Bonesini - 22/10/05 RAL 17
Solenoid test magnet (B up to 50 gauss) Test solenoid, PMT inside Laser diode Avtech pulser M. Bonesini - 22/10/05 RAL 18
R 4998 PMT rate studies R 4998 with modified divider circuit: booster or active divider for last dynodes Nominal: up to 1. 5 MHz M. Bonesini - 22/10/05 RAL 19
Gain in magnetic field for R 4998 50 Gauss 90 degs 50 gauss 90 degs M. Bonesini - 22/10/05 RAL 20
Timimg properties of R 4998 in B field M. Bonesini - 22/10/05 RAL 21
Rate effects studies for R 4998 • done with available R 4998 with modified divider from Hamamatsu (booster on last dynodes) 1 MHz • Light signal corresponds to ~ 300 p. e. M. Bonesini - 22/10/05 RAL 22
Timing resolution vs rate for R 4998 Npe is estimated via absolute gain measure (at SER peak) M. Bonesini - 22/10/05 RAL 23
Continuos pulsing vs ISIS-cycle • Results for rate effects have been compared with a continuos pulsing rate R and simulating an ISIS-like cycle : 1 ms at rate R + 20 ms at no rate • Results (as expected) show no difference M. Bonesini - 22/10/05 RAL 24
Final considerations for TOF 0 PMTs choice tests are under way, but active divider seems a good option no problem for rate effects ESSENTIAL POINT: to estimate for real final counters Npe (this determines rate behaviour) -> counters prototypes available // cosmic testbench available M. Bonesini - 22/10/05 RAL 25
Back of the envelope calculation Intrinsic resolution Concerns 1) Light attenuation & Timing degradation with respect to distance from PMT. 2) Quality of scintillator 3) Ageing effect Needs evaluation with cosmics testbench M. Bonesini - 22/10/05 RAL 26
TOF 0 planning 1. 2. 3. 4. 5. 6. Nov 05: decide L, W scintillator and place orders (EIJLEN vs BICRON) -> needs final AUG 05 rate maps at TOF 0 End 05: define choice between booster/active divider for R 4998 (tests+cosmic testbench for Npe)-> needs definitive B field maps at TOF 0 Parasitic testbeam with MEG friends at BTF: asap -> check TOF 0 performances up to PMT output (st + rate behaviour with e-) Mid 2006: combined testbeam with EMCAL at BTF -> define electronic readout (V 1290 ? TDCs) End 2006: define calibration scheme (cosmics+ laser) End 2006/beg 2007: buy FE electronics, laser calibr. system, HV … Items 1 -6 funded (~120 KE); no funding yet for items 6 But good news: Sofia group is interested in TOF business, so we can be more confident on this schedule. We will define actual division of work later, according to interests. A Pavia group (still working on PMT tests) is planning to join TOF effort M. Bonesini - 22/10/05 RAL 27
TOF 1/TOF 2 design is still based on SEP 04 beamline design But timescale is less critical (as respect to TOF 0) New point: final B-field calculations after shielding of J. Cobb et al. Main result is that at PMT positions B//~200 G, B_|_ ~ 1000 G -> fine-mesh PMTs need additional -metal shielding M. Bonesini - 22/10/05 RAL 28
News from AUG 05 from T. Roberts Beam envelope seems smaller Reduce TOF 1/TOF 2 size ? M. Bonesini - 22/10/05 RAL 29
|B| at TOF for 7 configurations of Iron Discs & Gap Calculations from J. Cobb, maybe some work can be done to shape shielding to change the relative weight of B//, B_|_ M. Bonesini - 22/10/05 RAL 30
Considerations for TOF 1/TOF 2 PMT choice 1. Rate capability (up. 5 MHz on full detector) 2. Good timing properties (TTS) 3. Sustain magnetic field ( about. 1 -. 2 T for TOF 2) Tests at Lasa magnet test facility with Pavia MEG group to optimize choice (M. Bonesini, F. Strati INFN Milano, G. Baccaglioni, F. Broggi, G. Volpini INFN Milano –LASA, G. Cecchet, A. De. Bari, R. Nardo’, R. Rossella INFN Pavia, S. Dussoni, F. Gatti, R. Valle INFN Genova). From MEG experiment M. Bonesini - 22/10/05 RAL 31
Tests done at LASA Laser source to simulate MIP signal (about 300 p. e. ) : fast PLP-10 laser on loan from Hamamatsu Italia Laser sync out triggers VME based acquisition (TDC + QADC) 5000 events for each data point : different PMTs (fine-mesh vs mod R 4998), different Bfield, different inclination vs B field axis ( ), diff laser rate to simulate incoming particle rates M. Bonesini - 22/10/05 RAL 32
Used laser light source Light source: Hamamatsu fast laser ( 405 nm, FWHM 60 ps, 250 m. W peak power) PLP-10 Optical system: x, y, z flexure movement to inject light into a CERAM/OPTEC multimode fiber (spread 14 ps/m) PMT under test Laser light Signal ~ 300 p. e. to reproduce a MIP as measured with an OPHIR Laser powermeter M. Bonesini - 22/10/05 RAL 33
Test magnet at LASA (B up to 1. 2 T) PMT under test 1. B field up to 1. 2 T 2. Free space 12 cm in height q M. Bonesini - 22/10/05 RAL For other tests : shielded conventional PMTs, we will refurbish the magnet, enlarging the gap up to 18 -20 cm (field will go down to ~. 4 -. 5 T) 34
Fine Mesh Photomultiplier Tubes Secondary electrons accelerated parallel to the B-field. Gain with no field: 5 x 10 5 – 10 7 With B=1. 0 Tesla: 2 x 104 - 2. 5 x 10 5 Prompt risetime and good TTS Manufactured by Hamamatsu Photonics R 5505 R 7761 R 5924 Tube diameter 1” 1. 5” 2“ No. Of stages 15 19 19 Q. E. at peak . 23 . 22 Gain (B=0 T) 5. 0 x 10 Gain (B= 1 T) 1. 8 x 10 4 1. 5 x 10 5 2. 0 x 10 5 Risetime (ns) 1. 5 2. 1 2. 5 TTS (ns) 0. 35 0. 44 5 1. 0 x 10 7 M. Bonesini - 22/10/05 RAL 35
Gain in B field (various orientations) G(B)/G(B=0 T) G(T)/G(0) B PMT axis 2” > critical angle: this points to mu-metal shielding for TOF 1/2 M. Bonesini - 22/10/05 RAL B(T) 36
Time resolution M. Bonesini - 22/10/05 RAL 37
Rate effects (as a function of HV) • rate capability is limited by max anode mean current (tipically 0. 1 m. A for a 2” R 5924 PMT) • this is the ONLY relevant point, e. g. in B field if gain is lower by a factor F rate capability increases by 1/F • With very high particle rates: try to reduce mean current M. Bonesini - 22/10/05 RAL 38
Rate effect as function of B field M. Bonesini - 22/10/05 RAL 39
Timing resolution vs rate • Tests with MCA Ortec TRUMP 8 K+ TAC Ortec 566 and CF discriminator ORTEC CF 8000 • Timing resolution is not affected by rate R • It depends as expected from Npe M. Bonesini - 22/10/05 RAL 40
Timing resolution vs rate Conventional R 4998 PMT with active divider M. Bonesini - 22/10/05 RAL 2” fine-mesh PMT 41
Rate effects Question: any difference between rate capability in continuos pulse mode or in accelerator-like pulsed mode ? Answer: no, as clear from the fact that rate capability is driven only by max Ia bunched mode at rate R Continuos mode at rate R M. Bonesini - 22/10/05 RAL 42
TOF 1/TOF 2 planning Not yet funded from INFN: funds are up to now for TOF 0 up to PMTs (no electronics, calibration system, HV). But design seems less challenging than TOF 0 (similar, lower rates, even if with higher B field) We will do some R&D/design work in parallel with TOF 0, to avoid delays After funding, delivery may be end 2007/beginning 2008: main bottlenecks (aside manpower) are delivery times for PMTS (4 -5 months), scintillator (3 -4 months) M. Bonesini - 22/10/05 RAL 43
Estimate of costs TOF 0 PMT assembly R 4998 (1600 Euro x 40) 64 K Euro scintillators Lightguides machining/supports/… i Electronics mountingsi/patch panels/dividers HV/signal cables 10 K Euro 5 K Euro 3 K Euro 87 K Euro TOF 1 (or TOF 2) PMT assembly 2” fine-mesh (2500 Euro x 35) scintillators Lightguides machining/supports/… Electronics mountingsi/patch panel/dividers HV/signal cables Laser cal syst Fast laser + fibers bundle Front-end electronics 10 K Euro 5 K Euro 3 K Euro 110. 5 KEuro 60 K Euro laser diagnostics, electronics Cosmics cal syst 87. 5 KEuro 5 K Euro 65 KEuro scintillators, support, … 10 K Euro QADC, TDC 40 K Euro Discriminators 10 K Euro NIM electronics Crate VME HV supply Got up to now ~110 KE (+ ~ 50 KE in-kind material) 5 K Euro 8 K Euro 63 KEuro 100 channels CAEN + mainframe 35 K Euro Total 481 KEuro M. Bonesini - 22/10/05 RAL 44
Main open points FE electronics (V 1290 TDC with TOT corrections instead of V 775 TDC + V 792 QADC)… but this rate problem is common to all MICE detectors Fix beamline to define final geometry of scintillator counters, mainly L, W: for TOF 0 an early answer is needed by November 05 Be completely sure of B field at TOF 0 well below 50 G Define by simulation the need of st ~ 60 ps for TOF 2 Define by simulation is calibration is feasible with only through-going muons, exploiting detector redundancy (X+Y strips) and … M. Bonesini - 22/10/05 RAL 45
Remaining … INFN funding : 1. Electronics, cal. System, HV for TOF 0 2. All TOF 1/TOF 2 (aside some modest R&D for defining design) 3. This mainly drives the TOF 1/TOF 2 timescale M. Bonesini - 22/10/05 RAL 46
Скачать презентацию M Bonesini MICE TOF stations INFN Milanoplanning construction
3b83b8ebac7c36e6025f664eb63e5777.ppt