atlas forward protons: a (10) picosecond window on the higgs boson andrew brandt, university of...

ATLAS Forward Protons: A (10) Picosecond Window on the Higgs Boson

Andrew Brandt, University of Texas at Arlington

A picosecond is a trillionth of a second.This door opens ~once a second, if it opened every 10 picoseconds it would open a hundred billion times in one second (100,000,000)

Light can travel 7 times around the earth in one second but can only travel 3 mm in 10 psec

Yes, I know it’s a door, not a window!

1January 12, 2010 Andrew Brandt SLAC Seminar

Outline

Part I: Introduction to ATLAS Forward Proton (AFP) proposal and physics motivation

Part II: Details of the AFP fast timing system


AFP: Proposes to use double proton tagging in conjunction with the ATLAS detector as a means to measure properties of

Higgs (quantum numbers+mass) and other new physics

ATLAS Forward Protons (AFP)

Central Exclusive Production (QCD) Central Exclusive Production (QED)

NEW

3CEP: Momentum lost by protons goes entirely into mass of central system

Central Exclusive HiggsAFP concept: adds new ATLAS sub-detectors at 220 and 420 m upstream and downstream of central detector to precisely measure the scattered protons to complement ATLAS discovery program.These detectors are designed to run at a luminosity of 1034 cm-2s-1 and operate with standard optics (need high luminosity for discovery physics)

Ex. The leading discovery channel for light SM Higgs, H , has a branching ratio of 0.002!

You might ask: “Why build a 14 TeV collider and have 99% of your energy taken away by the protons, are you guys crazy or what??”

beam

p’

p’AFP Detector

LHC magnets

The answer is “or what”!—ATLAS is always (or at least for a few weeks last December) losing energy down the beam pipe, we just measure it accurately!!!

420 m 220 mH

Note: the quest for optimal S/B can take you to interesting places:

4

5

SM Higgs Branching Ratio

MH= 140 GeV( ) ( *)Br H bb Br H WW

• We know (we think) that the Higgs gives

particles mass through their coupling to the Higgs field

• Theory constraints imply that the Higgs is “light” < 200 GeV

(not soooo light)

• Various channels contribute discovery sensitivity depending on the exact Higgs mass

( ) 0.002Br H

Andrew Brandt SLAC Seminar

• 2000 Khoze, Martin, Ryskin (KMR): Exclusive Higgs prediction Eur.Phys.J.C14:525-534,2000, hep-ph/0002072

• 2003-2004: joint CMS/ATLAS FP420 R&D collaboration forms• 2005 FP420 LOI presented to LHCC CERN-LHCC-2005-0254 “LHCC acknowledges

the scientific merit of the FP420 physics programme and the interest in exploring its feasibility”

• 2006-2007 Significant R&D funding in UK, modest funding in U.S. and other countries, major technical progress, RP220 formed

• 2008 RP220 and AFP420 merge to form AFP, R&D continues, Cryostat design finalized with CERN, LOI to ATLAS submitted

• 2009 “AFP year in review”, FP420 R&D document published in

J. Inst (2009_JINST_4_T10001)• Nov. 2009 ATLAS approves AFP to develop a Technical Proposal

6

AFP Evolution

January 12, 2010 Andrew Brandt SLAC Seminar

7

Who is AFP?Institute CountryUniversity of Alberta CanadaCharles University, Prague Czech RepublicInstitute of Physics Czech RepublicIRFU-SPP, CEA Saclay FranceJustus-Liebig-Universität Giessen GermanyCalabrian University ItalyInstitute of Nuclear Physics, Cracow PolandGlasgow University UKManchester University UKCockcroft Institute/Manchester University UKRutherford Appleton Laboratory - PPD UKRutherford Appleton Laboratory - EID UKUniversity College, London UKUniversity of Texas at Arlington USAState University of New York (StonyBrook) USA

Other institutions have expressed interest—there is plenty to do!


What is AFP?

1) Impressive array of rad-hard edgeless 3D silicon detectors (same sensors to be used in IBL upgrade) with resolution ~10 m, 1rad

2) Timing detectors with ~10 ps resolution for overlap background rejection (SD+JJ+SD)—more on this in Part Deux3) New Connection Cryostat at 420m4) “Hamburg Beam Pipe” instead of Roman Pots

AFP is a rather vanilla name for this precision instrument: I prefer VF3DSPDwithPST!

(Very Forward 3-D Silicon Proton Detector with Picosecond Timing)

For more information: e-mail me at [email protected] or better yet, come to bonus session Su Dong has arrangedat 3 pm


mailto:[email protected]

AFP in Pictures

9

Test Beam

proton

phot

ons

QUARTIC

Movable beam pipehouses 3-D silicon andtiming detectors

New connection cryostatwith integrated movablebeam pipe houses 3-D silicon and timing detectors

Timing detectors to reject background where protons and central system come from different interactions in same bunch crossing

1 Cryostat (warm-cold transition)2 Support table for movable beampipe3 Detector station4 Vacuum valve


What does AFP Provide?

420-420

420-220

220-220

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• Mass and rapidity of centrally system

• where 1,2 are the fractional momentum loss of the protons (ex. =0 for elastic proton)

• Mass resolution of 3-5 GeV per event

1 2M s Acceptance >40% for wide range of resonance mass

Allows ATLAS to use LHC as a tunable s glu-glu or colliderwhile simultaneously pursuing standard ATLAS physics program

1 2

1ln( / )

2y

Combination of 220and 420 is key to physics reach!

“+” “=”

What is Special about CEP?

• Extra “screening ” gluon conserves color, keeps proton intact (and reduces your )

• CEP defined as ppp+X+p , where protons are scattered at small angles, but remain intact, with all of their lost energy going towards production of the system X

• Central system produced in Jz=0++ (C-even, P-even) state, this results in di-quark production being suppressed

• More importantly: if you observe any resonance (for ex. Higgs), you automatically know its quantum numbers are 0++

pp gg H +x pp p+H+p

TypicalHiggs Production

CEPHiggs

11Find a CEP resonance and you have measured its quantum numbers!!

January 12, 2010

1) Observation of Exclusive Dijets : (CDF) PR D77, 052004 (2008) σ(excl, jetETmin = 15 GeV) 112+84-50 pb. In agreement with ExHuME MC which incorporates Khoze, Martin, Ryskin (KMR) model for CEP (x3 theor. uncertainty) Why we care: same diagram as Higgs but with u/d loop instead of top loop 2) Observation of Exclusive χc : (CDF) PRL 102, 242001 (2009) dσ/dy(y=0) = 76 +/- 10 +/- 10 pb. Prediction (KMRS) = 90 pb Why we care: same diagram as Higgs but with c loop instead of top loop

These support the prediction of KMR for standard model Higgs at the LHC (3 fb @ 120 GeV)

Does CEP Process Exist?

CDF says yes!

Since the KMR SM Higgs cross section prediction is pretty small: ~3fb, most of the recent theoretical work has focused on BSM Higgs, which can lead to enhanced cross sections for

1) MSSM (H->bb, H->ττ, H->WW*)– Heinemeyer, Khoze, Ryskin, Stirling, Tasevsky, Weiglein [Eur.Phys.J.C53:231-256,2008]– Cox, Loebinger, Pilkington [JHEP 0710:090,2007]

2) NMSSM (H->4τ)– Forshaw, Gunion, Hodgkinson, Papaefstathiou, Hodgkinson, Pilkington [JHEP 0804:090,2008]

3) CP-violating Higgs sector (H->bb, H->ττ)– Ellis, Lee, Pilaftsis [Phys.Rev.D71:075007,2005]– Cox, Forshaw, Lee, Monk, Pilaftsis [Phys.Rev.D68:075004,2003]

4) Triplet Higgs (H->bb)– Chaichian, Hoyer, Huitu, Khoze, Pilkington [JHEP 0905:011, 2009]

Phenomenological Studies of BSM Higgs

13

pp pHp H bb

I will go through a few details of MSSM and then get back to the SM Higgs


MSSM Higgs sector• In order to implement electroweak symmetry breaking into the MSSM,

two Higgs doublets (H1, H2) are needed.

8 degrees of freedom

3 are absorbed from the H mechanism and give masses to W± and Z (as for SM Higgs)

5 physical Higgs bosons

2 CP even (h, H), 1 CP odd (A) and 2 charged H±

The MSSM Higgs sector (at tree level) is determined by 2 free parameters: MA and tanβ=v2/v1 ( the ratio of the vacuum expectation values of

the 2 Higgs doublets)

Courtesy of Giorgos Dedes Seminar : Physik am Large Hadron Collider (LHC)14January 12, 2010 Andrew Brandt SLAC Seminar

15

For the MSSM and related models, AFP is likely to provide the only way to determine the Higgs quantum #’s and the coupling to b-quarks, and will provide an excellent mass measurement.

MSSM and CEPModels with extended Higgs sectors, such as the MSSM, typically produce a light Higgs (h) with SM-like properties and a heavy Higgs (H) which decouples from Gauge boson. This implies:•no HVV coupling (V=W, Z)• no weak boson fusion• no HZZ• big enhancement in

• pseudoscalar A does not couple to CEP

H bbH

R=(MSSMH)/(SMH)tan

mA (GeV)

R=300H→bb, mhmax, μ = 200 GeV

• Heinemeyer et al.

studied CEP coverage of MSSM parameter space in

mA-tan plane.

• Plots show the 5σ contours for the light Higgs scalar boson (above) and heavy (below) for 60fb-1 and 600fb-1.

• For large tan , Tevatron can already exclude part of the region.

5 contours, Hbb

MSSM Higgs discovery/exclusion

16

h/H→bb, mhmax, μ = 200 GeV

TeV

LEP

• Pick: tan=40, mA=120 GeV, mh=120 GeV (MSSM h/SM H =8) and do detailed analysis including experimental efficiencies determined using TDR resolutions.

Observing Higgs in the MSSM Cox. et.al. (JHEP 0710:090,2 007)

Better pileup rejection


H4 in the NMSSM

• NMSSM Higgs sector consists of 3 neutral scalars and 2 neutral pseudo-scalars (and charged Higgs).

• Most ‘natural’ part of parameter space results in light scalar Higgs (~100 GeV) Haa (`a’ is lightest pseudo-scalar)

• Preferred decay of pseudo-scalar is a (thus two a’s4 taus).

• ATLAS standard search channels are difficult and likely cannot measure the Higgs quantum numbers

• Predict approx 7 CEP events after ~100fb-1 with no appreciable background (JHEP 0804:090,2008). (Trigger on e tau decays)

• BONUS: information from forward protons gives good pseudo-scalar mass measurement!


HWW* in the SM and MSSM• Cox et.al. (Eur.Phys.J.C45:401-407,2006)

showed that the semi-leptonic decay of SM HWW* was possible for 130< mH <200GeV, using single muon/electron triggers for 30fb-1 of data.

• Also have golden fully leptonic decay channel: small signal but negligible background.

• Note: in the MSSM, cross section can be enhanced for lighter Higgs boson in the WW* channel as well by up to a factor of 4 relative to SM cross section.

Enhancement with respect to SM

19Andrew Brandt SLAC SeminarJanuary 12, 2010

• AFP manpower primarily dedicated to detector R&D and technical studies, however… • We performed ATLFast and Full Sim studies over the last few years to validate the predictions choosing 120 GeV for and 160 GeV for

•We validated the exclusivity cuts needed to reduce the overlap background, including tracking rejection with full detector simulation, trigger studies etc., but I can’t tell you about that yet!

AFP Internal Studies

H bb *H WW


Exclusive two-photon processes are characterized by exchange of virtual photons from protons. Photon fusion results in a system X of particles centrally produced and two intact protons, scattered at small angles.[1]

[1] K. Piotrzkowski, Phys.Rev.D63(2001) 071502: Tagging two-photon production at LHC[2] Louvain photon group, arXiv: 0908.2020, High-energy photon interactions at the LHC

Central Exclusive Photon-Photon

Does it exist? Yes. Q.E.D. (a little Latin humor)

For pair production, significant cross-sections (fb-level) are expected [2], with clean and unambiguous final states. Offers a novel possibility for the search of BSM particles

21

1) P.J. Bell, arXiv:0907.52992) C. Royon, E. Chapon, O. Kepka, arXiv:0909.5237 ; O. Kepka,, C. Royon, (DAPNIA, Saclay) Phys. Rev.

D78:073005,2008.

Event counting: for AFP trigger on 2 high pT leptons (WW)

95% CL limits for the AQGC for L=30fb-1:

>103 improvement over LEP limits, and 3-8x ATLAS w/o AFP

•The inclusion of AFP is critical for rejection of background from parton-parton production of W pairs. (cross-section x BR x lepton acceptance = 1pb)•Potentially sensitive to Higgsless models or other new physics

Anomalous Quartic Gauge Couplings

22

LEP (Opal)

ATLAS no AFP 1)

ATLAS w/AFP 2)

2 x 10-2 2 x 10-5 2.6 x 10-6

4 x 10-2 3.2 x 10-5 9.4 x 10-6

2/Woa

2/Wca

Charged SUSY Production• Photon-photon production of charged SUSY pairs investigated in

arXiv:0806.1097.• Benchmark points consistent with WMAP data examined.• Fully leptonic final states considered:

– Two forward protons measured in forward detectors

– Two leptons with opposite charge. (pTe > 10GeV, pT

> 7GeV).

5 discovery with 25 fb-1 for light SUSY scenarios

N.Schul and K.Piotrzkowski, arXiv: 0806.1097, Detection of two-photon exclusive production of susy pairs at the LHC23

• CEP dijets: measure unintegrated PDFs and can be used to calibrate jet energy scale • Diffraction: extends studies at HERA and Tevatron on dPDFs, survival probabilities

(relevant to VBF)• Hard SD and DPE: dijets - sensitive to gluon dPDFs

SD B-meson -sensitive to gluon dPDFs

SD W/Z - sensitive to quark dPDFs

SD Top – because we can• p: jet production to study the factorisation breaking in direct and resolved processes

observed by H1, extend to xp<0.1

• single top: measure CKM matrix element V_tb • anomalous single-top: study anomalous single-top coupling • Odderon interaction in • Charged Higgs in

24

But Wait, There’s More…


AFP SummaryAFP will provide ATLAS with a new sub-detector enabling a rich

complementary physics program (our physics is your physics)

Central Exclusive Production (QCD)

• With sufficient luminosity, BSM Higgs bosons can be observed in

CEP in a variety of mainstream models, many of them non-trivial for

standard ATLAS techniques

• The WW* channel looks very promising for SM Higgs of 130 GeV or above.

• CEP provides excellent mass resolution

• Observing CEP Higgs determines quantum numbers (0++)

Central Exclusive Production (QED)

• Superb anomalous quartic gauge coupling sensitivity could uncover new physics

• Complementary SUSY sensitivity .

Plus a variety of SM physics and speculative physics. Note: theoretical investigations of AFP capabilities are still in early stages.


FP420/AFP Fast Timing

10 ps or better (to get x20 rejection)

Use time difference between protons to measure z-vertex and compare with tracking z-vertex measured with silicon detector

Background Rejection for Diffractive Higgs

Ex: Two b-jets from one interaction and two protons from another

WHO? UT-Arlington (Brandt), Alberta, UC-London, Prague, Saclay, Stonybrook, Giessen, Manchester, Fermilab, Louvain, Kansas

WHY?

How?

How Fast?26January 12, 2010 Andrew Brandt SLAC Seminar

Ultra-fast Timing Issues

• 3 mm =10 ps• Radiation hardness of all components of system• Lifetime and recovery time of tube• Backgrounds• Multiple proton timing

Time resolution for the full detector system:1. Intrinsec detector time resolution2. Jitter in PMT's3. Electronics (AMP/CFD/TDC)4. Reference Timing


Timing System Requirements

• 10 ps or better resolution• Robust: capable of operating with little or no

intervention in radiation environment (tunnel)• High efficiency • Acceptance over full range of proton x+y• Segmented (multi-proton timing)

• Two main options: 1) one very precise measurement (GASTOF) 2) multiple less precise measurements (QUARTIC)

Andrew Brandt SLAC Seminar 28January 12, 2010

FP420/AFP Timing

Two types of Cerenkov detector are employed:

QUARTIC – two QUARTIC detectors each with 4 rows of 8 fused silica bar allowing up to a 4-fold improvement over the single bar 40 ps measurement

GASTOF – a gas Cerenkov detector that makes a single 10 ps measurement

Both detectors use Micro Channel Plate PMTs

(MCP-PMTs)


Photocathode

Dual MCP

Anode

Gain ~ 106

Photoelectron

V ~ 200V

V ~ 200V

V ~ 2000V

photon

+

+

e-

Faceplate

MCP-PMT

Micro-Channel Plate Photomultiplier Tube

(MCP-PMT)

30

ATLAS Solution: Option 2)

• Choosing multiple measurements with modest resolution on 30-40 ps scale simplifies requirements in all phases of system

1) We have a readout solution for this option (later) 2) We can have a several meter cable run to a lower

radiation area where CFD’s can be located, while TDC’s can be located even further away (the cable distortion is much more significant for sub-10 ps measurement)

3) Segmentation is natural for this type of detector

Andrew Brandt SLAC Seminar 31January 12, 2010

QUARTIC Ray Tracing

20 ps

~ 5 pe’s accepted in 40 ps

40 ps

40 ps

~ 10 pe’s accepted in 40 ps

15mm Quartz/75 mm air

90mm Quartz

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QUARTIC Prototype

Testing long bars 90 mm (HE to HH) and mini bars 15 mm (HA to HD) Long bars more light from total internal reflection vs. losses from reflection in air light guide, but more time dispersion due to n()

HE

HH

HC

Note: prior to June 2008 test beam, results marginal for QUARTIC 15mm bar: 80 ps/bar 80% efficient; allows you to reach close to 20 ps, but not 10 ps

33

Dt

QUARTIC Timing 2008 CERN TB

56.6/1.4=40 ps/bar using Burle 64 channel 10 mpore tube including CFD!

Time difference between two 9 cm quartz bars after Louvain constant fraction implies a single bar resolution of 40 ps for about 10 pe’s (expected 10 pe’s from simulations). Need to demonstrate N (more later)

Npe=(area/rms)2

34

2 21 2 1

1

( ) ( ) 2

so if 1 2 then / 2

t t t t

t t

6 mm

6mm

Eve

nts

Strip #

Eff

icie

ncy

(a) (b)

(c)

QUARTIC Efficiency CERN TBAll tracks(Bonn SiliconTelescope)

Tracks witha Quartz bar on

Use tracking (b)/(a) to determine that QUARTIC bar efficiency is high and uniform

Shape due to vetocounterwith 15mmdiameterhole

35

Timing Progress in 2009

• Established UTA Picosecond Test Facility (PTF) for laser tests

• Developed in depth understanding of MCP-PMT performance

• Investigated rate and lifetime issues

• Formed collaborations with Arradiance, Photek, and Photonis (including submission of UK and UTA funding proposals)

• Built a new prototype detector

• Validated readout electronics

• Albrow obtains 20-30 ps for a single 90 mm QUARTIC bar with single channel Photek 3 m pore PMT (T979 at FNAL)


• The baseline QUARTIC detector could see rates of up to 15 MHz in the hottest 6mm x 6mm pixel of the MCP-PMT. If the current:

Anode Current = proton frequency x number of photo-electrons generated by each proton x charge x gain

is too high (~10% of strip current) the tube saturates (gain is reduced)• To keep the current at tolerable levels, lower gain and less pe’s are

desirable, but precise timing requires as many pe’s as possible (and conventional wisdom also indicated that high gain was necessary*). Smaller pores both reduces the current in any one pore and improves the timing

• With 10 pe’s expected for a QUARTIC bar, if a gain of 5x104 were possible instead of the canonical 106(!), we would require a maximum current of about 3 A/cm2, a factor of several higher than standard MCP-PMT’s, but possible for new generation of Photonis MCP-PMT’s

37

Rate and Current Limits

peI R N e G

*Stay tuned for laser test results!

Lifetime IssuesLifetime due to positive ions damaging the photocathode is believed to be proportional to extracted charge: Q/year = I*107 sec/year Q at maximum luminosity is up to 35 C/cm2/yr ! (assuming 5x104 gain!)

Without a factor of 20 reduction in gain, the current and lifetime issues would make MCP-PMT’s unusable, with itthe rate is borderline, but lifetime off by a factor of 50—tube dies every week!

38

Solution: Graduate student camps out in tunnel to exchange tubes as needed. (Sorry Ian)

Lifetime MeasurementsN. Kishimoto, et al., Nucl. Instr. and Meth. A 564 (2006) 204.

Aluminum ion barrier layer on top of MCP suppresses positive ions, increases lifetime by x5 to 6

Relative QE as function of wavelength shows damage is much less in UV than visible

Barrier

No barrier

Options for Improved Lifetime MCP-PMT• Ion barrier, already demonstrated, this promises a factor 5 to 6 lifetime

improvement (at the cost of a 40-50% collection efficiency reduction)

• Electron scrubbing, already demonstrated internally by Photonis, promises a factor 5 to 10 lifetime improvement

• Z-stack, already demonstrated, this promises a factor of 10 lifetime improvement (A.Yu. Barnyakov, et al., Nucl. Instr. and Meth. A 598 (2009) 160)

• Arradiance coated MCP’s, to be demonstrated, this promises a factor of 10 or more lifetime improvement (Grants submitted by UTA and Manchester to fund insertion of Arradiance MCP’s in Photonis and Photek tubes: “Development of a Long Life Microchannel Plate Photomultiplier Tube for High Flux Applications through the Innovative Application of Nanofilms”)

• Various combinations of these factors are possible and should give multiplicative improvement factors, except for the electron scrubbing and Arradiance coating, which would be expected to be orthogonal


Conclusions of Internal Lifetime NoteCombination of lower gain running and higher current tube implies that expected rates/currents at 1034 are acceptable with existing technology.

After accounting for lower gain running the discrepancy factor for the lifetime required for tube to survive 1 LHC year at 1034 luminosity is about a factor of 50 at 220 m as current QUARTIC detector design require a 35 C/cm2 MCP-PMT

Pursuing the funding necessary to develop 50x longer life MCP-PMT’s. Given the different possible lifetime options, we have no doubt that this can be achieved with MCP-PMT technology


Laser Test Goals• Develop flexible laser test facility• Study properties of MCP-PMT’s• Optimize electronics Some issues to address:

1) How does timing depend on gain ?

2) What is minimum gain for 10 pe’s? Need to validate low gain operations.

3) What is maximum rate at which tube can operate?

4) Evaluate amp/CFD/TDC choices at detector working point

5) Eventually lifetime tests


LeCroy Wavemaster 6 GHz Oscilloscope

Laser Box

Hamamatsu PLP-10 Laser Power Supply

43

laserlenses

filterMCP-PMT

beam splittermirror

PTF

Picosecond Test Facility featuring Undergraduate Laser Gang (UGLG)Undergraduate Laser Youths? (UGLY)


Timing vs Gain for 10 m Tube

Measured with reference tube using CFD’s and x100 mini-circuits amps, with 10 pe’s can operate at ~5E4 Gain(critical for reducing rate and lifetime issues) With further optimization have obtained <25 ps resolution for 10 pe’s.

44

45

Timing vs. Number of PE’s

No dependence of timing on gain if sufficient amplification!

Transit Time Spread for Burle 64 Channel Planacon (10 m pores)

• Jerry Va’vra has measured 32 ps for TTS (SLAC-PUB-13573) so we should have about 10 ps (32/10 for 10 pe’s! )

• This is true only if you ignore 2nd backscattering peak

January 12, 2010 Andrew Brandt SLAC Seminar 46

UTA Transit Time Spread for Burle 64 Channel Planacon (10 m pores)

testing/modelling of responseof PMT to late light and evolution of timing from one to several pe’s in progress

48

Current/area for 10 m Tube

Last 2 points are 0.4 and 2.0 μA/cm2; we need to reach about 3 μA/cm2 at 1034 Photonis has made Planacon with 10x higher current capability which would meet our rate requirements(even with saturation we still obtain the same time resolution!!!)


New Multi-Channel Laser Setup


Rate Tests

50

No rate dependence on number of pixels hit (that’s a good thing!)


Beam vs Fiber

Fiber timing not as good, but allows us flexibility for some characterization tests51January 12, 2010 Andrew Brandt SLAC Seminar

If single fiber gives 35 ps then 4 fibers should give 17 ps; but note that with many fibers plugged in, individual pixel gets light leaking from neighboring channel, need to test that this effect is reproduced in test beam

SQRT(N)?

From averaging time of four measurements on event-by-event basis

52

Components of AFP Fast Timing System

QUARTIC:Photonis planacon10 m pore 8x8 or equivalent Photek MCP-PMT

Mini-circuits ZX603 GHZ or equivalent

Louvain Custom CFD (LCFD)

HPTDC board(Alberta)

Reference Timing

Opto-modules/

ROD

HV/LV

UTA QUARTIC/PMT Development

Stonybrook AMP to HPTDC

Manchester/UCL

Ref. timeSLAC +LLNL<1 ps !

LCFD

Louvain developed LCFD (Louvain ConstantFraction Discriminator)mini-module approachtuned LCFD mini-moduleto Burle and Hamamatsu risetimes; 12 channel NIM unitExcellent performance : <10 ps resolution for 4 or more pe’s

Remote control for threshold

ZX60 3 GHz amplifier


Alberta HPTDC board

12 ps resolution with pulser. Successfully tested at UTA laser test stand with laser/10 m tube/ZX60 amp/LCFD

55

LCFD_Ch01_No12_spe, high level light, May 6, 2009, UTA laser test RMS resolution = 13.7 ps

0

1000

2000

3000

4000

5000

6000

800 810 820 830 840 850 860 870 880 890 900

bin number

coun

ts

13.7 pswith splitLCFD signalJanuary 12, 2010

Fast Timing Summary

• Have tested detectors and electronics chain capable of ~10 ps timing

• R&D still in progress to optimize all components (and reduce rate/pixel)

• Prototype system test beam including readout planned for this summer

• PMT lifetime is an ongoing issue, but pursuing options with vendors that seem likely to provide solutions on 3 year timescale (prior to max luminosity)


AFP allows ATLAS to cover all the possibilities!


atlas forward protons: a (10) picosecond window on the higgs boson andrew brandt, university of...

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