1. TOF for 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 10 34 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

2. 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 420- 420 420- 220 220- 220 Acceptance >40% for wide range of resonance mass Combination of 220 and 420 is key to physics reach! Mass and rapidity of centrally produced system Mass resolution of 3-5 GeV per event

3. 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 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 3 UTA, Alberta, Giessen, Stonybrook (w/help from Louvain and FNAL) MCP-PMT

4. 4 Micro-Channel Plate Photomultiplier Tube Burle/Photonis 64 channel 10 and 25  m pore 64 channel MCP-PMT has been tested extensively with test beam and laser and would be default for first stage except for lifetime issues

5. MCP-PMT Requirements Excellent time resolution: 20-30 ps or better for 10 pe’s High rate capability: I max ~ 3  A/cm 2 Long Lifetime: Q ~ 30 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 5 Photek 240 (1ch) Hamamatsu SL10 (4x4)

6. Dt QUARTIC Timing 2008 CERN TB 56.6/1.4=40 ps/bar using Burle 64 channel 10  m pore tube including CFD! Time difference between two 9 cm quartz bars after CFD implies a single bar resolution of 40 ps for about 10 pe’s (10 pe’s from simulations/Test Beam). N pe =(area/rms) 2 6

7. 6 mm Events Strip # Efficiency (a) (b) (c) QUARTIC Efficiency CERN TB All tracks (Bonn Silicon Telescope) Tracks with a Quartz bar on Use tracking (b)/(a) to determine that QUARTIC bar efficiency is high and uniform Shape due to veto counter with 15mm diameter hole 7

8. Beam Mode Fiber Mode (a) (b) (d) (c) 8 UTA Laser System

9. Time Resolution from Laser Tests 9 Laser tests of 10 µm tube show that with sufficient amplification there is no dependence of timing on gain (low gain operation extends lifetime of tube)

10. 10 Saturation from Laser Tests Saturation independent of number of pixels hit, with proposed glass can obtain required rate

11. 11 Electronics Layout  t~25ps  t~5ps  t~15ps

12. 12 LOI approved, Technical Proposal being prepared UK groups funding cut leaves a hole/creates opportunity We have developed a fast timing system for AFP that seems to be capable of ~10 ps resolution, still some loose ends to address, requires R&D funding Work in progress: 1) final optimization of detector 2) developing final HPTDC board and trigger circuit 3) test beam analysis and laser tests (including studies of multiple proton effects, lifetime) 4) developing and testing long-life MCP-PMT (need funding) 5) evaluating radiation tolerance of all components Status