140 likes | 258 Views
Tests of Fast Timing Detectors in the Meson Test Beam (T979) MTest : May 27 th – June 2 nd. Mike Albrow, Sasha Pronko, Erik Ramberg, Anatoly Ronzhin, Andriy Zatserklyaniy + detector simulations by Hans Wenzel & Earle Wilson (student). Motivations for ~ ps / 10 ps timing detectors
E N D
Tests of Fast Timing Detectors in the Meson Test Beam (T979)MTest : May 27th – June 2nd Mike Albrow, Sasha Pronko, Erik Ramberg, Anatoly Ronzhin, Andriy Zatserklyaniy + detector simulations by Hans Wenzel & Earle Wilson (student) • Motivations for ~ ps / 10 ps timing detectors • Set-up and triggers etc. • Detector configurations: • A – B – C in line • A+B transverse bars – C • C) Q-bar1(A) – Q-bar2(B) – C • D) Aerogel(C) – B • E) Si-PMTs • F) Photonis1 – Photonis2 – C in line • G) Q-bar1(A) – Q-bar2(B) – 8.7 m flight path --- C in line • Thoughts about next steps To be explained! Only if you ask!
Motivations: Timing on single particles σ(t) typically >~ 100 ps A factor 10 – 100 improvement likely to have unforeseen benefits. We know of some (foreseen), e.g.: 2 1 Particle ID in large detectors (~CDF-like or ILC) E.g. at 6 GeV/c, over 1.5m: Δt(π-K) = 17 ps Δt(K-p) = 43 ps ================== Areas ~several m2, want thin. Argonne-Chicago- (Henry Frisch et al.) Fermilab group Particle ID in beams E.g. at 25 GeV/c, over 15m: Δt(π-K) = 20 ps Δt(K-p) = 50 ps or at 10 GeV/c, over 30m: Δt(π-e) = 10 ps ================== Areas ~few cm2, want thin. 3 Pile-up reduction e.g. in FP420: Extensions to CMS & ATLAS in prepn. p + p p + H + p + nothing else Measure p’s M(H), J, C, P, Γ 4 • PET-TOF • β+e Δt = 10ps : Δz = 3mm 240m … 420m CMS H 240m … 420m p p
Pile-up reduction in FP420 Want L ~ 10^34, <n> ~ 25/x ? z(vertex) from pp == z(vertex) central cf σ(z)vtx ~ 60 mm to CMS Exec Board Summer 2008 (ATLAS is also reviewing)
At MTest, 120 GeV/c p, ~40,000/spill Simple trigger (schematic): 2mm x 2mm scint. VETO w/hole 2 PMTs in AND 2 PMTs in OR First A-B-C in line Dark & shielded box 210 C A B PHOTEK 210 2 MCP, 10mm Φ PHOTEK 240 2 MCP, 40mm Φ Calibrate electronics resolution with same pulse start & stop: σ~ 3 ps Cerenkov light in Quartz window. HV ~ 4.5 kV, G ~ 5.10^5 Schematic DAQ : ADC DAQ MCP- PMT-A ORTEC 566, 567 TAC/SCA T1 ORTEC AD114 ADC ATTENUATOR MCP- PMT-B ATTENUATOR ADC
A-B-C in-line results: Cerenkov light in PMT windows All numbers “preliminary”, to be double-checked ADC distributions: cut out tails and stragglers (~ 10%) T1 = tA – tB T2 = tA – tC T3 = tB – tC ======= Check Ti(PH A,B) Make slewing corrections Unfold: A B C etc. PMT-1 (Photek-210, 4.7 kV)=12.0 psPMT-2 (Photek-210, 4.6 kV)=12.0 psPMT-3 (Photek-240, 4.2 kV)=7.7 ps Cerenkov light in PMT windows
Double Q-bar Quartz (fused silica) bars 6mm x 6mm x 90mm PHOTEK 210 Mounted at Cherenkov angle θc ~ 48deg. on opposite sides. dz = 6mm/sin(48) = 8.1mm. Some light direct to PMT, ~1/2 TIR to PMT Black “sock” over bars just to avoid light sharing Unfold: σ(A) = 22.3 ps σ(B) = 30.5 ps B Includes electronics (~3 ps) and 2 mm beam width smear (A,B) Δt = 2 mm x (10 ps/2 mm) C A Combining [AB] removes beam spread (later, tracking)
Resolution of Double-Qbar as one device * σ = 6.04 ch = 18.7 ps Unfold C = 7.7 ps, σ(AB) = 17.0 ps Resolution of double-Qbar 2 mm x-spread not to be subtracted (only 3 ps electronics) * Derivation in back-up
Switched on, saw signals! A = Aerogel B Corrected T2 = A-B = 10.8 ch = 33.5 ps (before unfolding)
Aerogel results: Unfolding indirect because only 2 PMTs in run. A (Aerogel on 240) and B(210 in beam) T1 = t(A) – t(B) corrected for smearing: 10 mm aero σ(T1) = 43.7 ps 20 mm aero σ(T1) = 45.3 ps 30 mm aero σ(T1) = 33.5 ps <P.H.> = 46 ch. (10mm) 72 ch. (30 mm) Unfold with σ(1) = 12 ps from in-line σ (Aerogel 30 mm) ~ 31 ps Aerogel + mirror ~ massless & short (~ 5 cm), simple. Can have several in line, independent √N BUT: have large 240 tube close to beam Possibilities to focus light : smaller tube farther away, to be simulated MCP-PMT AEROGEL
Tests of SiPMs = silicon photomultipliers Eight Hamamatsu SiPMs, 3mm x 3mm In beam with quartz Cherenkov radiators several thicknesses (4 – 12mm), mirrored and not mirrored. Best conditions σ(t) ~ 33 – 37 ps 10-15 photoelectrons Channels Between SiPMs and C. Slewing correction applied
World’s Best Beamline Time-of-Flight System? Start = Double-Q-bar Stop = Photek 240 Start-stop dist. = 8.7 m Predictions of proton positions 24 psec resolution positron peak, Using average of A & B times Can measure momentum of a proton with 2 MCP-PMTs! (if you know it’s a proton!)
Possible Next Steps For FP420 a σ(t) = 10 ps edgeless detector we learnt a way including CMS-compatible electronics/DAQ with reference time signals (jitter <~ 5 ps) Should get < 8 ps θc = 48deg Q-bars onto PHOTEK 240 MCP-PMTs 20mm 6mm x 6mm bars TIR: isolated MCP I “beam” only 6mm vert., 20 mm horiz. MCP 40 mm diam. MCP p + More aerogel? To test in Fall?
We thank: PHOTEK Ltd (UK) for loan of MCP-PMTs Accelerator Division Ops for beam, and patience over many accesses Jim Pinfold and Don Summers for gift of aerogel Carl Lindenmeyer and John Korienek for Q-bar support Rick Coleman for low energy beams Hogan Ngyuen & SiDet dept. for many things LHC beam From FP420 R&D doc.
Back Up Why: T1 = A - BT2 = A - CT3 = B - C ------------T1 + T2 = A - B + A - C3 x T3 = 3B - 3Cso T1 + T2 + 3x T3 = A - B + A - C + 3B - 3C = 2A + 2B - 4Cand 1/4 ( T1 + T2 + 3x T3 ) = (A+B)/2 - C