M. Bonesini - 22/10/05 RAL1 M. Bonesini INFN Milano MICE TOF stations construction & planning

M. Bonesini - 22/10/05 RAL2 Outline  Introduction  Present design for TOF0  PMTs studies  Current problems  Funding & timescale  Present design for TOF1/TOF2  PMTs studies  Open questions (TOF0/TOF1/TOF2)  Conclusions

M. Bonesini - 22/10/05 RAL3 Aims of TOF stations TOF0 experiment trigger TOF0/TOF1 PID on incoming muons TOF1/TOF2 PID on particle traversing the cooling channel TOF1/TOF2 contribute (t) to emittance measurement (  t ~60 ps has been questioned by INFN referees for TOF2) Detector requirements: o Single detector resolution  ~60 ps o High rate capability o Sustain nearby not-uniform B fringe fields

M. Bonesini - 22/10/05 RAL4 TRD SEPT04 Layout TOF0 TOF1 Ckov1 Iron Shield TOF2 Ckov 2Cal ISIS Bea m Diffuser Proton Absorber Iron Shield

M. Bonesini - 22/10/05 RAL5 …MICE ToF0 Cherenkov Calorimeter Focus Coils Coupling Coils Liquid Hydrogen Absorbers RF Cavities Tracking Spectrometers Matching Coils Beam Diffuser Tof1 Tof2

M. Bonesini - 22/10/05 RAL6 TOF0 design is presently based on SEP04 beamline (mods may be foreseen for AUG05) Particle rates was around MHz for TOF0, it seems that new beamline AUG05 will reduce it to ~ 1.6 MHz -> better if beam profile will not shrink in AUG05 TOF0 in the fringe field of quadrupoles for TOF0 B << 50 gauss (mail from Kevin). Conventional fast PMTs Hamamatsu R4998 with booster or active divider+mu-metal shielding

M. Bonesini - 22/10/05 RAL7 Summary of Rates (Sept04 from Tom Roberts) DescriptionLAHETGeant4MARS TOF TOF Tracker Tracker TOF Good μ Values are events per millisecond of Good Target; absorbers empty, no RF. Good μ + = TOF0 & TOF1 & Tracker1 & Tracker2 & TOF2 & TOF1(μ + ) & TOF2(μ + ) Major changes from before: 2 in. total thickness of TOF0 and TOF1  ~20% reduction in Good μ+ ~50% larger target acceptance  ~10% increase in TOF0 singles, ~1% in Good μ +.

M. Bonesini - 22/10/05 RAL8 Rates (Singles per ms) target insertion reduced to get 600 good mu+/sec (AUG05) LAHETGeant4MARSAverage TOF TOF Tracker Tracker TOF Good μ + (Ev/sec)

M. Bonesini - 22/10/05 RAL9 Some simulation studies: TOF0 TRD Size 480x480 SEPT04

M. Bonesini - 22/10/05 RAL10 TOF0 X/Y singles projection SEP04 beamline (TRD) has fixed counter size to L=48 cm, W= 4cm (T= 1”)

M. Bonesini - 22/10/05 RAL11 TOF0 AUG05 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 We keep design as it is now for the present time

M. Bonesini - 22/10/05 RAL12 Scintillator counter layout based on present beamline assumptions for all TOF stations L=480 mm, T=1”, W=40 mm for TOF0, 600 mm for TOF1/2. Choice between BC404/420 scintillator or ELJEN Technology 230 (~same quality) To be revised with AUG05 beamline design: but soon, orders must be placed now for scintillator. Mainly I must fix L,W for TOF0 EJ230BC420BC404 Light output 64 % 68% max 391 nm 408nm Risetime0.5 ns 0.7 ns Decay time1.5 ns 1.8 ns Pukse FWHM 1.3 ns 2.2 ns Att length-140 cm Seems a better choice

M. Bonesini - 22/10/05 RAL13 Mechanics for TOF0 View of X/Y plane: 12 vertical counters, 12 horizontal counters

M. Bonesini - 22/10/05 RAL14 TOF0 support structure No major changes foreseen up now

M. Bonesini - 22/10/05 RAL15 Considerations for TOF0 PMT choice 1. Rate capability (up to some MHz) 2. Good timing properties (TTS) 3. Sustain magnetic field (we now assume <<50 gauss for TOF0)

M. Bonesini - 22/10/05 RAL16 Conventional PMT test setup Laser source to simulate MIP signal (about 300 p.e.) : fast AVTECH pulser AVO-9A-C (risetime 200 ps, width ns, repetition rate 1KHz-1MHz) with NDHV310APC Nichia violet laser diode(~400 nm, 60 mW) 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 RAL17 Rate capabilities of PMTs To have a linear signal the mean average anode current (100  A for R4998 ) must not be exceeded -> damage to dynodes... shorter PMT lifetime This gives a theoretical rate capability of: 267 KHZ with R4998 BUT !!! Divider can be modified for R4998 (going up to 1.67 MHZ) with booster or active divider

M. Bonesini - 22/10/05 RAL18 Solenoid test magnet (B up to 50 gauss) Test solenoid, PMT inside Avtech pulser Laser diode

M. Bonesini - 22/10/05 RAL19 R4998 PMT rate studies R4998 with modified divider circuit: booster or active divider for last dynodes Nominal: up to 1.5 MHz

M. Bonesini - 22/10/05 RAL20 Gain in magnetic field for R degs 0 degs 50 gauss 90 degs 50 Gauss

M. Bonesini - 22/10/05 RAL21 Timimg properties of R4998 in B field

M. Bonesini - 22/10/05 RAL22 Rate effects studies for R4998 done with available R4998 with modified divider from Hamamatsu (booster on last dynodes) Light signal corresponds to ~ 300 p.e. 1 MHz

M. Bonesini - 22/10/05 RAL23 Timing resolution vs rate for R4998 N pe is estimated via absolute gain measure (at SER peak)

M. Bonesini - 22/10/05 RAL24 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 RAL25 Final considerations for TOF0 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 N pe (this determines rate behaviour) -> counters prototypes available // cosmic testbench available

M. Bonesini - 22/10/05 RAL26 Back of the envelope calculation Concerns Intrinsic resolution 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 RAL27 TOF0 planning 1. Nov 05: decide L,W scintillator and place orders (EIJLEN vs BICRON) -> needs final AUG05 rate maps at TOF0 2. End 05: define choice between booster/active divider for R4998 (tests+cosmic testbench for N pe )-> needs definitive B field maps at TOF0 3. Parasitic testbeam with MEG friends at BTF: asap -> check TOF0 performances up to PMT output (  t + rate behaviour with e-) 4. Mid 2006: combined testbeam with EMCAL at BTF -> define electronic readout (V1290 ? TDCs) 5. End 2006: define calibration scheme (cosmics+ laser) 6. 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 RAL28 TOF1/TOF2 design is still based on SEP04 beamline design But timescale is less critical (as respect to TOF0) 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 RAL29 News from AUG05 from T. Roberts Beam envelope seems smaller Reduce TOF1/TOF2 size ?

M. Bonesini - 22/10/05 RAL30 Calculations from J. Cobb, maybe some work can be done to shape shielding to change the relative weight of B//, B_|_ |B| at TOF for 7 configurations of Iron Discs & Gap

M. Bonesini - 22/10/05 RAL31 Considerations for TOF1/TOF2 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 TOF2) 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. DeBari, R. Nardo’, R. Rossella INFN Pavia, S. Dussoni, F.Gatti, R. Valle INFN Genova). From MEG experiment

M. Bonesini - 22/10/05 RAL32 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 R4998), different B- field, different inclination vs B field axis (  ), diff laser rate to simulate incoming particle rates

M. Bonesini - 22/10/05 RAL33 Used laser light source Light source: Hamamatsu fast laser (  405 nm, FWHM 60 ps, 250 mW 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 RAL34 Test magnet at LASA (B up to 1.2T) PMT under test 1.B field up to 1.2 T 2.Free space 12 cm in height  For other tests : shielded conventional PMTs, we will refurbish the magnet, enlarging the gap up to cm (field will go down to ~.4-.5 T)

M. Bonesini - 22/10/05 RAL35 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 x 10 5 Prompt risetime and good TTS Manufactured by Hamamatsu Photonics R5505R7761R5924 Tube diameter1”1.5”2 “ No. Of stages1519 Q.E.at peak Gain (B=0 T)5.0 x x 10 7 Gain (B= 1 T)1.8 x x x 10 5 Risetime (ns) TTS (ns)

M. Bonesini - 22/10/05 RAL36 Gain in B field (various orientations) G(T)/G(0) 2” B(T) G(B)/G(B=0T) PMT axis B   > critical angle: this points to mu-metal shielding for TOF1/2

M. Bonesini - 22/10/05 RAL37 Time resolution

M. Bonesini - 22/10/05 RAL38 Rate effects (as a function of HV) rate capability is limited by max anode mean current (tipically 0.1mA for a 2” R5924 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 RAL39 Rate effect as function of B field

M. Bonesini - 22/10/05 RAL40 Timing resolution vs rate Tests with MCA Ortec TRUMP 8K+ TAC Ortec 566 and CF discriminator ORTEC CF8000 Timing resolution is not affected by rate R It depends as expected from N pe

M. Bonesini - 22/10/05 RAL41 Timing resolution vs rate Conventional R4998 PMT with active divider 2” fine-mesh PMT

M. Bonesini - 22/10/05 RAL42 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 I a bunched mode at rate R Continuos mode at rate R

M. Bonesini - 22/10/05 RAL43 TOF1/TOF2 planning Not yet funded from INFN: funds are up to now for TOF0 up to PMTs (no electronics, calibration system, HV). But design seems less challenging than TOF0 (similar, lower rates, even if with higher B field) We will do some R&D/design work in parallel with TOF0, 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 RAL44 Estimate of costs TOF0 PMT assembly R4998 (1600 Euro x 40) 64K Euro scintillators 10K Euro Lightguides machining/supports/… i 5K Euro Electronics mountingsi/patch panels/dividers 5K Euro HV/signal cables 3K Euro 87K Euro TOF1 (or TOF2) PMT assembly 2” fine-mesh (2500 Euro x 35) 87.5KEuro scintillators 10K Euro Lightguides machining/supports/… 5K Euro Electronics mountingsi/patch panel/dividers 5K Euro HV/signal cables 3K Euro 110.5KEuro Laser cal syst Fast laser + fibers bundle 60K Euro laser diagnostics, electronics 5K Euro 65KEuro Cosmics cal syst scintillators, support, … 10K Euro Front-end QADC,TDC 40K Euro electronics Discriminators 10K Euro NIM electronics 5K Euro Crate VME 8K Euro 63KEuro HV supply 100 channels CAEN + mainframe 35K Euro Total 481 KEuro Got up to now ~110KE (+ ~ 50KE in-kind material)

M. Bonesini - 22/10/05 RAL45 Main open points FE electronics (V1290 TDC with TOT corrections instead of V775 TDC + V792 QADC)… but this rate problem is common to all MICE detectors Fix beamline to define final geometry of scintillator counters, mainly L,W: for TOF0 an early answer is needed by November 05 Be completely sure of B field at TOF0 well below 50 G Define by simulation the need of  t ~ 60 ps for TOF2 Define by simulation is calibration is feasible with only through-going muons, exploiting detector redundancy (X+Y strips) and …

M. Bonesini - 22/10/05 RAL46 Remaining … INFN funding : 1.Electronics, cal. System, HV for TOF0 2.All TOF1/TOF2 (aside some modest R&D for defining design) This mainly drives the TOF1/TOF2 timescale