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Electronics and Trigger developments for the Diffractive Physics Proposal at 220m from LHC-ATLAS

Electronics and Trigger developments for the Diffractive Physics Proposal at 220m from LHC-ATLAS. By P. Le Dû. pledu@cea .fr. J.F. Genat 1 , O. Kepka 2 , P. Le Dû, Ch. Royon For the RP220 collaboration. 1 CNRS/IN2P3 2 DAPNIA.SPP and Institute of Physics, Prague, Czech Republic.

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Electronics and Trigger developments for the Diffractive Physics Proposal at 220m from LHC-ATLAS

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  1. Electronics and Trigger developments for the Diffractive Physics Proposal at 220m from LHC-ATLAS By P. Le Dû pledu@cea.fr J.F. Genat1, O. Kepka2 , P. Le Dû, Ch. Royon For the RP220 collaboration 1 CNRS/IN2P3 2 DAPNIA.SPP and Institute of Physics, Prague, Czech Republic Hwaii 2007 -N43-4

  2. Goals of this presentation • Present the feasibility study, R&D and issues for the development of detectors to measure protons at 220 m from the IP, within low  optics at the LHC • Work associated or/and in collaboration with • FP420 for the position detector (3D) • See N18-4 and N20-4 • UChicago/ANL/FNAL/Saclay/Photonis(Burle) for the ultra fast timing detector (MCP) • N06-6 and N18-1 Hwaii 2007 -N43-4

  3. Diffractive physics • Main physics aim pp  p+ X + p • Exclusive Higgs Signal over background: ∼ 1 if Mass resolution < 1Gev • New physics :SUSY search, Diffractive top, stop pair production • QCD studies • Photon induced interactions • Objective : reconstruct the M with a precision better than 1 Gev • Kinematics variable is •  = fractional momentum losses of the outgoing protons b-jet H h p p M2= = 12 S b-jet Hwaii 2007 -N43-4

  4. RP220 vs. other projects Luminosity Monitors (Low Luminosity) • High Luminosity 1033 to 1034 • Additional signal and flag at the L1 ATLAS Trigger • Natural follow-up of the ATLAS luminosity project at 240 m to measure total cross section • Complementary to the FP420 ATLAS RP220 FP420 Hwaii 2007 -N43-4

  5. Trigger topologies RP220 only PL. AND PR track with ζ cut Et JET 1 AND 2 > 40 Gev JET Rapidity correlation ? Dijet ENERGY /TOTAL > 0,9 JET 1 PLtrack RP 220 RP 220 1 KHz @ 1033 20-30 KHz @ 1034 PR track JET 2 RP220 + FP420 PL track with ζ cut Et JET 1 AND 2 > 40 Gev JET 1 Rapidity Cut Dijet ENERGY /TOTAL > 0,9 JET 1 PL Track RP 220 FP420 1,6 KHz @ 1033 JET 2 Hwaii 2007 -N43-4

  6. Basics Requirements and Challenges • Measure  of each outgoing proton • Position and direction with a precision of 10  • Time of Flight (TOF) of the 2 outgoing protons with a resolution of < 5 picoseconds • General system issues • Mechanics and overall stability • integration with precision beam position monitor to reach 0(10) m • Radiation for detectors at 220 meters (cryostat region) • Detectors to operate very close to the beam (10  --> 1 mm) • Trigger/selection issues Hwaii 2007 -N43-4

  7. Accumulated dose estimation @ 220 m (XRP3) N. Mokhov, LHC Report 633 Hwaii 2007 -N43-4

  8. Position Detectors • Position detectors • Need to approach beam to the mm level and stabilty of 10 m • Should Achieve 10 mm position resolution • Use EDGELESS Silicon detectors TOTEM Roman pot technique For compact detectors Hwaii 2007 -N43-4

  9. Timing detectors • Measure the Time Of Flight of each diffracted proton • Precision of few Picoseconds • 1 mm on the vertex (select the right event among 35) • Technology --> Micro Channel Plate (MCP) moving beampipe (HERA) Hwaii 2007 -N43-4

  10. Roman Pots location RP RP RP RP 220m 220m IP RP RP RP RP { Each RP station consists of two Roman Pot Units separated by 8 m, centered at 220m from IP1 { Roman Pot Station Roman Pot Unit Hwaii 2007 -N43-4

  11. Roman Pots Layout 8m Beam Optics IP 220m Elastic events for calibration and alignment Hwaii 2007 -N43-4

  12. Layout MCP-PMT Y U X X V Radiator 8 x 8 Pixels 3D pixels Light Guide Size : 2,5 x 2,5 cm2 S I D E D O W N MCP MCP UP Roman Pot B Roman Pot A Timing detector Movable Beam Pipe 2 x 21 planes of Si detectors Hwaii 2007 -N43-4

  13. Position detectors specific requirements • Objective : Achieve 10 mm position resolution • Two staggered 50 mm pitch strips read in digital : • 25 / 12 = 7.2 mmresolution • Or larger pitch analog using centroids • Trigger data available within a few 100 ns • Candidates: • Baseline: “3D” Pixels detectors (S. Parker) • - NEW : Under development for RP420 • Stanford, VTT, Sintef • - Backup: Edgeless Silicon strips Experienced technology • Canberra, Hamamatsu 3D (Stanford) Semi-3D detector (VTT, Finland) 50mm strips (Canberra) Hwaii 2007 -N43-4

  14. 3D Detector • Benefits compared to standard Si strips detectors) • - Collection time x 10 2 ns • - Low voltage depletion /10 10V • - Radiation hardness x50 1015 p/cm2 • - Edgeless using plasma etching /10 5mm • - Same charge as planar 25 ke-/300 m • Drawbacks • -Thickness: Needs a bump-bonded chip • (could be thinned to 50mm) • - Production yield Presently 80% • (7.2 x 8 mm2 detectors) • - Readout speed Slow as is: 2-6 ms, • - No ‘fast’ trigger data Hwaii 2007 -N43-4

  15. FE13 Readout chip (ATLAS b-layer upgrade) • 2880 channels • 50 x 400 mm2 pixels • 7.2 x 8 mm2 • Binary & Time Over Threshold • Self triggering • Time over Threshold • Adjustable threshold • CMOS 250nm IBM • Readout 2-6 ms @ 40 MHz 8mm 7.2mm Readout chip Baseline for FP420 Need to be modified for extracting the Fast Trigger information IZM + Bonn Hwaii 2007 -N43-4

  16. Fast (asynchronous) pixels digital readout Trigger data 10-bit words X1 Y1---Y1n X2 Y21---Y2m -- -- Xp Yp---Ypq 512 pixels - Fast ORs of columns (sufficient for the RP220 trigger) Fast readout of every hit column Fast address building takes a few ns in total (130nm CMOS) - Can be sent to the fast logic in the “alcove” at every BCO - Data transfer: 10 hits (disable noisy pixels) = 20 (10) words = 200 (100) bits 20ns (10) @ 10 Gb/s Hwaii 2007 -N43-4 Jean-François Genat, RP220 meeting, Oct 17-19th 2007 Krakow, Poland

  17. Alternative Read Out solution • Pixels connected as strips • Standard ABCD strips readout • Capacitance is higher, but does not impact small detectors Need to extract the Fast OR signal for trigger Hwaii 2007 -N43-4

  18. Micro Channel Plate PMT Operation photon Faceplate Photocathode DV ~ 200V Photoelectron Dual MCP DV ~ 2000V MCP-OUT Pulse Gain ~ 106 DV ~ 200V Anode A 2” x 2” MCP actual thickness ~3/4” Burle- Photonis MCP 2” x 2” sensitive area Hwaii 2007 -N43-4

  19. Major advance for generating the signal Incoming rel. particle Use Cherenkov light ­ fast Custom Anode with Equal­Time Transmission Lines + Capacitative. Return Collect charge here ­differential Input to 200 GHz TDC chip Development of MCP’s with 6-10 micron pore diameters e.g. Burle (Photonis) 85022­with mods 10 mm pores Hwaii 2007 -N43-4

  20. Simulation • RF Transmission Lines • Summing smaller anode pads into 1by 1readout pixels • An equal time sum­ make transmission lines equal propagation times • Work on leading edge­ ringing not a problem for this fine segmentation Ability to simulate electronics and systems to predict design performance Oscillator with predicted jitters << 100 femtosec 860 fs 20 Pe Hwaii 2007 -N43-4

  21. Read Out :Direction to reach 1(few) psec (1) • Picking the time • Multithreshold discriminator M C P 1 2 3 4 Extrapolated time Hwaii 2007 -N43-4

  22. Direction to reach 1 psec (2)Time Stretcher Scheme “Slow” TDC k d d Resolution: a few ps • Issues • Power consumption (250 mWatts/ch) • Ramp zero crossing induces important Jitter IBM 8 HP Chip M C P DAQ Chip 200 MHz TDC (FPGA) Fukung Tang et al (UC-ANL). 1 2 3 4 Synoptic Hwaii 2007 -N43-4

  23. Direction to reach 1(few) psec (3) DC level to ADC ADC dt Digitized dt • Alternative to Time stretcher • Replace the TDC ---> ADC Hwaii 2007 -N43-4

  24. Best results with 2 TOF counters in tandem Hwaii 2007 -N43-4 From J. Va’vra (SLAC)

  25. Diffractive Trigger T - 224 m - 216 m 7 plans Si /Roman Pot  positionmicrons  time < 5 psec xA xB jet Horizontal roman pots (a la TOTEM) Front end T R PA SH jet xA xB Left Pretrigger Right Pretrigger +730 ns ATLAS detector T xD - xC =0 xA - xB =0 1,0 sec • LR Trigger Logic • LP AND RP • TR - TL Pipeline buffer (6.4 sec) +850 ns (air cable) 2,0 sec ATLAS standard 2 Jets with Pt > 40 Gev/c L1 CTP 2,5sec Max 75KHz R O D Refined Jet Pt cut Vertice within millimeter  time < 5 to 10 psec HLT Trigger (ROB) Hwaii 2007 -N43-4 US15 ATLAS Standard 30 nov 2006

  26. Timing and Data flow BXing 0 ns 733 ns Proton @ RP Flight path RP ASIC & FPGA SI ---> 4 Events x 2 Si Strips x 10 bit words MCP ---> 4 Events x 6 bit words per Xing = 104 bit/Bx Average Rate = 4,16 Gbit/sec (11ns through cable to Alcove) 1024 ns Pretrigger Data available @ 220 m(Alcove) Processing ALCOVE CTA crate PRETRIGGER Matching 2RPs with overlap Si Strips Add Timing information from relevant MCP PMT pixel (1 mm2)) Detector response 11 ns ABCD response 150 ns 20 ms cable 80 ns Pretrigger Processing 50 ns 1921 ns 80 bit/BX x 40 MHz = 3,2 Gb/s 80 bit @ 10 GB/s - 880 transfert time RP Triigger Data @ ATLAS CTP Cable Max 2500 ns LVL1 ACCEPT (75 KHz) 588 ns Processing 5120ns RPs data @ ROD Cable 2x 1100 ns + 7.4 K bit @ 4x 5 Gb/s= 2620 ns Data Production per Roman Pot to ROD 4 events x(7 Si detectors x10 bit word stored in the pipeline) 4 events x 1 MCP-PMT detector x (6 bit adress + 8 bit fine timing) Total per LV1 Accet = 336 bit Total x 75 KHz =25 Mb/s Hwaii 2007 -N43-4

  27. Implementation block diagram X X X X X X X X X X X X FPGA FPGA IP // MBP RP B RP A Picosecond CLK 160 MHz Trigger DATA 4,16 Gb/s RO DATA 670 kb/s Detector ASIC FPGA LHC CLK Local Logic RP Left Trigger ATLAS LVL1 CTP RP Right Trigger 1Cable L1 ACCEPT 20 m Cables ATLAS ROD (LVL2 & DAQ) DATA 2 x 3,2 Gb/s Pretrigger logic Read Out Control & Monitoring 4 fiberss CTA crate 75 KHz 25 Mb/s Shielded Alcove Reference clock (Atomic) 160 MHz CLK (fiber) US 15 LHC CLK Hwaii 2007 -N43-4

  28. Conclusions • A challenging ‘small’ experiment • Need to use State of the art technologies • Tracking Silicon hodoscopes with 10 m precision • Ultra fast timing with few Psec TOF resolution • Input signals forTrigger @ L1 in ATLAS • System aspect non obvious (stability, radiation …) But the Physics results might be outstanding ! Thanks a lot for your attention! Hwaii 2007 -N43-4

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