Fast Timing Developments Mike Albrow (Fermilab) ce 2000, exclusive p + X + p physics at high pile-up is only made po atic constraints, and (b) fast timing on both p’s, to get z(pp) to = e exception for X purely leptonic discussed separately) on the time difference σ(Δt) = 10 ps gives σz(pp) = 2.1 mm (3mm/√2) teractions) ~ 50 mm reduction factors ~ 25 can be achieved. F in HEP has σ ~ 100 ps. Our goal is 10 ps, but we are small (~ cm 2 ) ements: Radiation hard close to the beam, >= 1 year at 10 34 = 100 fb - one side (beam side) at ~ 200 μm or less x,y for multi-hit capability. for L1 trigger. out every bunch crossing at 25 ns. ion: Quartz Cherenkov counter bar hodoscope QUARTIC ng Cherenkov) pHp already in 2001 (hep-ex/0511057) (very part time) developed and tested.
Fast Timing Developments
Feb 22, 2016
Fast Timing Developments. Mike Albrow (Fermilab). As known since 2000, exclusive p + X + p physics at high pile-up is only made possible by (a) kinematic constraints, and ( b ) fast timing on both p’s , to get z(pp ) to = z(vertex ). - PowerPoint PPT Presentation
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Fast Timing DevelopmentsMike Albrow (Fermilab)
As known since 2000, exclusive p + X + p physics at high pile-up is only made possibleby (a) kinematic constraints, and (b) fast timing on both p’s, to get z(pp) to = z(vertex). (Possible exception for X purely leptonic discussed separately)A resolution on the time difference σ(Δt) = 10 ps gives σz(pp) = 2.1 mm (3mm/√2)With σ(z, interactions) ~ 50 mm reduction factors ~ 25 can be achieved.
Generally ToF in HEP has σ ~ 100 ps. Our goal is 10 ps, but we are small (~ cm2)
Other requirements: Radiation hard close to the beam, >= 1 year at 1034 = 100 fb-1
Edgeless on one side (beam side) at ~ 200 μm or lessSegmented in x,y for multi-hit capability.Fast signals for L1 trigger.Can be read out every bunch crossing at 25 ns.
Chosen solution: Quartz Cherenkov counter bar hodoscope QUARTIC(QUARtz TIming Cherenkov)
Proposed for pHp already in 2001 (hep-ex/0511057)Last 5 years (very part time) developed and tested.
Earlier HPS had a Gas ToF counter as well (Krzysztof Piotrzkowski) but nowwe only have QUARTIC: segmentation, multiple (4) measurements per track:Controls resolution, efficiency, time calibration, gives σ/2 and less stringent electronics
n > √2 (important)
First generation: Angled-bar QUARTICIsochronous at MCP. Only ~ 30% of lightgets to MCP, and only some of that directly.Bars are to side of beam, go up or down.Can have x segmentation, not y
Latest generation: L-bar QUARTICAll radiated light gets to detectorby total internal reflection.Can have one PD/bar, e.g. SiPMCan stack bars for x and y segmentation.
MCP-PMTs have a lifetime issue# photoelectrons, ~ LHC month?Being worked on.This is ATLAS AFP baseline
SiPMs have a radiation damage issue.Keeping them ~ 8-10 cm above and wellshielded we think this is OK (> 1 year)but need more tests. HPS baseline
2nd generation angled bar QUARTICsElectro-erosion machining (TIR)Springs & grease.
Got σ(t) = 16 ps each = 11 ps pairBut these MCP ~ $20K each, and may die.Also very close to beam.
L-bar QUARTIC test modules
2 boxes, each two 30mm and two 40mm barsSiPMs (Hamamatsu) readout.
2 L-bar boxes (4 modules) in test beam. Feb 2012
Can separate boxes for time shift calibration/check
Read out L-bars with waveform digitizer (scope)One event in one box:
GEANT simulations: Vladimir Samoylenko
Longer radiator bars improve time resolution
Amplitude adjusted to match observed (reflectivity)
Designing 24-channel L-Bar Quartic module(Steve Hentschel, Fermilab)
Bar arrangement:All SiPMs are in 5mm x 5mm space,with 3mm x 3mm active for bars.Light guide bars are ~ 10 cm long.
Bars are 20, 30 and 40 mm long.If needed one could (?) invert alternatemodules to have 20+40, 30+30 and 40+20 mm.Or bars are not flush at front (not favored)
Housing:Thin (100 um) sheet for opticalisolation (not structural).
Mounting for SiPM array board
BEAM
Notes: work in progress. Bottom below beam can be short.Thin wall not part of structure, only light shield.Light guides shorter if allowed. LGs can be in block of borated poly,with surrounding blocks. Front face encased in black glue, with crossedwire grids for 100 um spacing. Another x,y grid behind. Springs push matrix up.
System >> detector!
Detector box + SiPMs + SiPM board ... reasonably in hand.
Dimensions can be adjusted to fit
DAQ, triggers, data transmission, integration, software etc toget in place.
Thanks, Mike
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