ATLAS Forward Proton Upgrade AFP 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 cm -2 s -1 and operate with standard optics (need high luminosity for discovery physics) AFP Components 1)Rad-hard edgeless 3D silicon detectors with resolution ~10  m, 1  rad 2)Timing detectors to reject overlap background (SD+JJ+SD) 3) New Connection Cryostat at 420m 4) “Hamburg Beam Pipe” instead of Roman Pots beam p’ AFP Detector LHC magnets 420 m 220 m H Andrew Brandt, University of Texas, Arlington 1

What does AFP Provide? 2 Allows ATLAS to use LHC as a tunable  s glu-glu or  collider while simultaneously pursuing standard ATLAS physics program Acceptance >40% for wide range of resonance mass Combination of 220 and 420 is key to physics reach! Mass and rapidity of central system, assuming central exclusive production (CEP) process, where momentum lost by protons goes into central system Mass resolution of 3-5 GeV per event

3 P is for Proton P is for Proton, that’s good enough for me Forward Proton, Central Physics!

“+”“+” “=”“=” How does CEP work? Extra “screening ” gluon conserves color, keeps proton intact (and reduces your  ) CEP defined as pp  p+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 J z =0 ++ (C-even, P-even) state, this results in di-quark production being suppressed Process observed by CDF: exclusive dijets PR D77, (2008) and exclusive χ c PRL 102, (2009) pp  gg  H +xpp  p+H+p Typical Higgs Production CEP Higgs 4 Find a CEP resonance (for ex. Higgs) and you have measured its quantum numbers (0 ++ ) !!

5 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 CEP Models 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 H  ZZ big enhancement in pseudoscalar A does not couple to CEP R=  (MSSMH)/  (SMH) m A (GeV) R=300 H→bb, mhmax, μ = 200 GeV

2000 Khoze, Martin, Ryskin (KMR): Exclusive Higgs prediction Eur.Phys.J.C14: ,2000, hep-ph/ Joint CMS/ATLAS FP420 R&D collaboration forms 2005 FP420 LOI presented to LHCC CERN-LHCC “LHCC acknowledges the scientific merit of the FP420 physics programme and the interest in exploring its feasibility” Some R&D funding, major technical progress, RP220 formed 2008 AFP formed, cryostat design finished, LOI submitted to ATLAS 2009 “AFP year in review”, FP420 R&D document published “ The FP420 R&D Project: Higgs and New Physics with Forward Protons at the LHC,” FP420 Collaboration, arXiv: v2, published in J. Inst.: 2009_JINST_4_T10001, Nov AFP LOI approved, physics case acknowledged, encouraged to prepare Technical Proposal for AFP Evolution

August 5, 2010, A day that will live in infamy… UK funding for AFP project terminated (moment of silence) October 3, 2010 AFP institutions send letter to ATLAS management, Steve Watts resigns as project leader. 7 AFP Devolution

October 28, 2010 Christophe Royon, Interim Project Leader, meets with ATLAS management to discuss way forward for AFP November 11, 2010 ATLAS response -integrate with new ATLAS Forward Detector (FD) group (Chair Marco Bruschi) to get technical scrutiny -prepare technical proposal; after endorsement by FD group and ATLAS review AFP can be moved under Upgrade umbrella and be prioritized with other upgrade projects Our plan: a staged approach with 220 m system (at minimum movable beam pipe +infrastructure, but ideally pixel based tracker + timing detectors) installed in 2013 shutdown 420 m stations to be installed in 2016 shutdown 8 AFP Moving Forward

9 Current AFP Groups

10 Stage I: 220m Detector Stations New connection cryostat with integrated movable beam pipe houses 3-D silicon and timing detectors Movable beam pipe houses silicon and timing detectors (four of these stations at +/- 216 and 224m)

What is first step? Need to prepare Technical Proposal based on previous work for Feb./March Two months estimated for ATLAS review (!) If approved AFP will be official part of upgrade(to be prioritized). ATLAS management will then contact Accelerator Division to enable Hamburg pipe development starting April/May. Perhaps HPS can get started earlier? Who will develop Hamburg pipe? Initial work done by Louvain. UK funding for this (left over from NCC design work), but not authorized by ATLAS, funds subsequently retracted. Italian engineer identified, but group did not join AFP. Recent development, Alberta engineer may be available to work on this. When should it be installed? Ideally by late 2012 if no LHC run extension, else late Requires LHCC approval. What can we put in the Hamburg pipe? -Work in progress on adapting pixel detector for 220 m Stage I detector (Prague) -Developing Stage I timing detector: QUARTIC+full electronics chain (UTA, Alberta, Stony Brook, Giessen); GASTOF (Saclay) What about physics case for Stage I? QCD, di-photon, Higgless models (via anomalous coupling), extradimensions, high mass resonance searches 11 Stage I

12 Stage I Physics

13 Stage I Physics

14 Stage I: 220 m Collimator Issue

15 Stage I: 220 m BPM’s Need to identify manpower to work on this (uncovered in AFP). HPS?

16 Stage I: Silicon Pixel Detector

17 Stage I: Why Pixel and not 3D Propose to start with pixel detector instead of 3D due to resources available at Prague (with careful planning, should be straight forward to replace with 3D detector for Stage II). Note extra.3 to.5 mm dead space for pixel detector becomes important for Stage II, motivating 3D (also radiation issues?).

18 Stage I: Advantages 1)Trigger not required 2)No “significant” accelerator modifications (NCC not needed) 3)PMT lifetime not a big issue due to lower rates from lower lum, increased distance from beam (in fact, timing is mostly critical only for low mass states, such as light Higgs) 4) Less expensive _____________________________________________________ Lack of low mass acceptance motivates move to Stage II as soon as possible

19 Stage II: Add 420 m New connection cryostat with integrated movable beam pipe houses 3D silicon and timing detectors Requires NCC, 3D silicon, L1 trigger, 10 ps fast timing (with resolution of PMT lifetime issue or alternative detector)

20 Optimistic Timeline

10 picoseconds is design goal (light travels 3mm in 10 psec!) gives large factor of background rejection; Stage I: m lum up to several  t < 20 ps Stage II: 2016 add 420 m  t < 10 ps Use time difference between protons to measure z-vertex and compare with tracking z-vertex measured with silicon detector Pileup Background Rejection Ex: Two protons from one interaction and two b-jets from another Forward Proton Fast Timing WHY? How? How Fast?

Timing System Requirements 10 ps or better resolution Acceptance over full range of proton x+y Near 100% efficiency High rate capability Segmented : for multi-proton timing and L1 trigger Robust: capable of operating with little or no intervention in radiation environment (tunnel) - PMT’s, detectors, cables, and electronics must be able to tolerate radiation levels (for PMT’s this includes tolerance to external radiation damage, as well as to internal photocathode damage) - Backgrounds from other particles must not impair operation Andrew Brandt (UTA) AFP Workshop Prague 22Sep. 6, 2010

4x8 array of 5x5 mm 2 fused silica bars QUARTIC is Primary AFP Timing Detector Multiple measurements with “modest” resolution simplifies requirements in all phases of system 1) We have a readout solution for this option 2)We can have a several meter cable run to a lower radiation area where electronics will be located 3)Segmentation is natural for this detector 4)Possible optimization with quartz fibers instead of bars proton photons Only need a 40 ps measurement if you can do it 16 times: 2 detectors with 8 bars each, with about 10 pe’s per bar 23 UTA, Alberta, Giessen, Stonybrook MCP-PMT

MCP-PMT Requirements Excellent time resolution: ps or better for 10 pe’s High rate capability: I max ~ 3  A/cm 2 Long Lifetime: Q ~ 10 to 20 C/cm 2 /year at 400 nm Multi anode: pixel size of ~6 mm x 6mm Pore Size: 10  m or better Tube Size: 40 mm round, 1 or 2 inch square Need to have capability of measurements in different parts of tube between 0-2 ns apart, and in same part of the tube 25 ns apart 24 Hamamatsu SL10 (4x4) Photek 240 (1ch) Photonis Planacon (8x8)

Photocathode Dual MCP Anode Gain ~ 10 6 Photoelectron  V ~ 200V  V ~ 2000V photon + + MCP-PMT Arradiance coating suppresses positive ion creation (NSF SBIR Arradiance, UTA, Photonis) + Ion Barrier keeps positive ions from reaching photocathode (developed by Nagoya with Hamamatsu Use Photek Solar Blind photocathode or similar (responds only to lower wavelength/more robust) Increase anode voltage to reduce crosstalk (UTA)  V ~ 500V Gain < 10 5 Run at low gain to reduce integrated charge (UTA) Improve vacuum Seal (Nagoya/ Hamamatsu) A Long Life MCP-PMT e-e-

LeCroy Wavemaster 6 GHz Oscilloscope Laser Box Hamamatsu PLP-10 Laser Power Supply Andrew Brandt UTA 2610/14/2009 laser lenses filter MCP-PMT beam splitter mirror Established with DOE ADR, Texas ARP funds, some supplemental support for UG’s - Ian Howley (Ph. D. student), Ryan Hall (was UG, now in UTA Ph. D. program), both students moving on soon… - Monica Hew, Keith Gray, James Bourbeau (UG)+…

Beam Mode Fiber Mode (a) (b) (d) (c) 27 UTA Laser System

UTA Laser Results If N PE x Gain ≥ 5 x 10 5 then timing independent of HV/gain With sufficient amplification there is no dependence of timing on gain over x10 range Saturation the reduction in amplitude due to busy pores is a local phenomena Timing vs. Gain Tube will meet rate needs of AFP

29 Electronics Layout  t~25ps  t~5ps  t~15ps ZX60 4 GHz amplifier CFD Louvain, Alberta HPTDC Alberta Stony Brook SLAC UTA

Fermilab Test Beam Sunday Nov. 21 Setup 2 x2 mm Trigge r Scint Use 3mm siPM (with quartz bar) as reference timing for evaluating QUARTIC FNAL studying siPM; UTA studying QUARTIC

QUARTIC bar studies: Time Difference Between Adjacent Bars Time Difference between adjacent bars is <20 ps, implies <14 ps/bar including bar, PMT, CFD! Too good to be true, due to charge sharing and light sharing, bars are correlated. Time Difference between “distant bars” 4 and 7 is 37 ps, implies 25 ps/bar (better than QUARTIC design goals!!!) Strobing QUARTIC bars with siPM gives total resolution of ps/bar

Conclusions siPM-avg of 3 quartic bars reduced from ~28 ps (for single bar) to 21 ps consistent with  N expectations

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