AFP and HPS Forward Proton Projects Marek Taevsk Institute of - - PowerPoint PPT Presentation

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AFP and HPS – Forward Proton Projects

Marek Taševský Institute of Physics, Academy of Sciences, Prague, Czech rep. LISHEP 2011, Rio de Janeiro - 09/07 2011

History Physics with AFP/HPS Movable Beam pipe Tracking and Timing detectors

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Forward detectors around ATLAS and CMS

14 m 16 m 14 0 m 1 4 7 m

• 2 2 0 m

4 2 0 m

I P 1 I P 5

TOTEM -T2 CASTOR FSC ZDC TOTEM(now) HPS240 HPS420 LUCID ZDC ALFA(now) AFP220 AFP420

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Optimal places for AFP/HPS

Beam transposrt calculation by HECTOR JINST2, P09005 (2007) For nominal low-β* LHC optics

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AFP = ATLAS Forward Protons HPS = High Precision Spectrometer

Proton leaves the interaction intact, travels through LHC optics and is detected at ~220 m

AFP: 2 stations on each side with tracking and timing detectors at ~ 220m HPS: 2 stations on each side with tracking and timing detectors at ~ 240m 200-220m, ATLAS side Taken in May 2011 220-240m, CMS side Taken in Jan 2009

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History: FP420+FP220 → AFP & HPS

Michigan State Univ.

• Univ. of Chicago, Argonne (timing det.)

FP420 R&D Report JINST 4 (2009) T10001

+ FP220/240

ATLAS AFP R&D CMS HPS R&D

Upgrade Project Upgrade Project

2003 Manchester Forward Physics Meetings 2005 FP420 Joint ATLAS & CMS Collaboration 2008 FP420 R&D Report 2008 Add FP220 2009 Under review 2010-2011 Aim for Upgrade project

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History

Detector layout, Module assembly, Mechanical support, Sensor design, Edge response, Irradiation tests, Power supplies, Noise studies, Off-sensor readout, External services, Optical links, Detector control system, Full thermal modeling/stress During the R&D phase, a lot of things around tracking detector for FP420 (3D-Si oriented) have been done, investigated, proposed and worked out by UK and other institutes! After the drastic budget cuts in UK, AFP/HPS face manpower problems. Some solutions can be used for AFP220/HPS240. FP420 R&D Report JINST 4 (2009) T10001

ATLAS Technical Proposal:

AFP: A Proposal to install Proton Detectors at 220 m around ATLAS to Complement the ATLAS High Luminosity Physics Program (April 2011)

CMS Upgrade R&D Proposal:

R&D of the Detector Systems for Stage One of the High Precision Spectrometer Project (June 2010)

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AFP/HPS Concept

Add new ATLAS/CMS sub-detectors at 220/240 m (and later at 420 m) upstream and downstream of central detector to precisely measure the scattered protons to complement ATLAS/CMS physics program. These detectors are designed to run at 1034 and operate with standard optics. What t is is AF AFP/HPS? P/HPS?

1) Array of radiation-hard near-beam Silicon detector Silicon detectors with resolution ~10 m, 1rad 2) Timing detector Timing detectors with ~10 ps resolution for overlap background rejection (SD+JJ+SD) 3) Hambur Hamburg g Beam Pipe Beam Pipe instead of Roman Pots 4) New Connection Cryostat at 420 m

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AFP/HPS Time Scale

AFP/HPS asks for approval of: Building stations at 220/240 m during the long 2013-2014 shutdown 1) Hamburg movable beam pipes 2) Silicon detectors 3) Timing detectors 4) Precision Beam position monitors Physics: QCD, Diffraction, Two-photon, Extra dimensions, Higgsless models via quartic anomalous couplings Future upgrade (if motivated by physics): adding stations at 420 m 4) New Connection Cryostat at 420m 5) Upgrade or Replacement of Si detectors if necessary Physics: Mass acceptance and resolutions much improved => Diffractive Exclusive Higgs can be studied (or any other resonances)

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What does AFP/HPS Provide?

220+220 at IP1

9 AFP Andrew Brandt Barcelona October 9, 2009

• Mass and rapidity
• f centrally

produced system

• where 1,2 are the

fractional momentum loss of the protons

• Mass resolution of

3-5 GeV per event

1 2

M s   

Acceptance >40% for wide range of resonance mass

Allows ATLAS/CMS to use LHC as a tunable s gluon-gluon or  collider while simultaneously pursuing standard physics program

1 2

1 ln( / ) 2 y   

Diffraction Two-photon

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Diffraction at LHC:

• Forward proton tagging in special runs with

ALFA/TOTEM

• Combined tag of proton in Forward tagger on one

side and remnants of dissociated proton in LUCID/CASTOR on the other side

• Central rapidity gap in EM/HAD calorimeters

(|η|<3.2) and inner detector (|η|<2.5)

• Two rap.gaps on both sides from IP:

Inclusive Double Pomeron Exchange: parton from Pomeron brings a fraction β out of ξ into the hard subprocess → Pomeron remnants spoil the gaps Central Exclusive Production: β = 1 → no Pomeron/ Photon remnants

AFP/HPS Principal Physics: 1) Single tag (SD) 2) Double tag (DPE, CEP)

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Deflected protons at 220 m from IP1

Diffractive beam-1 protons deflected at 220m (IP1): - similar picture for IP5 Diffractive protons deflect horizontally in a region ~2x2 cm2

• utwards the

ring

1) Only horizontal detectors needed 2) Region of interest is ~2x2 cm2. (fully covered by exactly one ATLAS new FE-I4 chip – simplifies the sensor design!) 3) Acceptance 0.02 < ξ < 0.2 BEAM 1 10-15 σbeam LHC apertures Protons tracked through LHC optics using FPTrack or HECTOR

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Two-photon production

• J. De Favereau et al, arXiv: 0908.2020

Diffraction Photon induced processes

• Similar to diffraction, but smaller t
• di-lepton and WW production

dominate at small masses Exclusive di-leptons: Calibration candle for AFP/HPS Provides energy scale resolution of 10-4! Steeply falling mass spectrum: 420m: store-by-store calibration 220m: needs weeks to collect suff. statistics Exclusive WW: New Physics – Anomalous couplings

• Quartic couplings γγ→ WW, ZZ
• Precise test of the ElectroWeak sector
• Triple and quartic couplings reduce amplitude at HE
• Higgsless and Extra-dimension models predict

couplings to which AFP/HPS is sensitive (~10-6 GeV2)

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Exclusive di-leptons: LHC follows Tevatron

CDF: γγ→μ+μ-: PRL 102 (2009) 242001 γγ→e+e-: PRL 98 (2007) 112001

• J. Hollar, DIS2011

CMS 7 TeV, 2010 data (40 pb-1) pT,μ > 4 GeV |ημ| < 2.1 mμμ > 11.5 GeV2 148 events

Good description by LPAIR

• M. Albrow, LISHEP2011

Highest mass e+e- event

• C. Limbach, ATLAS

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Exclusive WW: Anomalous quartic couplings at high lumi

• P. J. Bell et al., EPJC64 (2009) 25
• K. Piotrzkowski et al., PRD 63 (2001) 071502
• O. Kepka et al. (ATLAS):

PRD81 (2010) 074003 σ(MWW) ~ 5 GeV Low background Sensitivity wrt OPAL Without AFP: 102 better With AFP : 104 better!

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Diffraction with small pile-up

• Large cross section (~30% of σinel -

serves to predict the effect of PU)

• One day of data taking in a special

run with negligible pile-up

• Calibrate gap size by ξ precisely

measured in AFP/HPS: Δη ~ -lnξ

• AFP/HPS gives information about

large mass spectrum Soft Diffraction ξ = (0.015, 0.2) → Δη = (~2, ~4) Hard Diffraction

PRD 77 (2008) 052004 Dijets in SD, DPE and CEP: Repeat CDF measurements.

SD: σ(SDjj)/σ(NDjj) = FD

jj(x)/Fjj(x) get FD

jj (β,Q2)

and S2 from known (HERA) PDFs . ξ< 0.1 → 0(1) TeV Pom. beams:  →~ 10-3 & Q2 ~104 GeV2 DPE: σ(DPEjj)/σ(NDjj): vary gap size → Sudakov effects and enhanced absorption CEP: Observed in CDF Reduce the factor 3 uncertainty in KMR predictions for LHC Measure Rjj and constrain unintegrated gluon density

SD CEP

[K. Goulianos, hep-ph/0407035]

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Possible Upgrade: add a station at 420 m

H→bb, nomix, μ = 200 GeV

Tevatron exclusion region LEP Exclusion region

EPJC 53 (2008) 231 & EPJC 71 (2011) 1649 using proposed FD(220&420)

• Experim. efficiencies from CERN/LHC 2006-039/G-124

Four luminosity scenarios (ATLAS+CMS):

60 fb-1; 60 fb-1 x 2; 600 fb-1; 600 fb-1 x2 SM: Higgs discovery challenging MSSM: 1) higher x-sections than in SM in certain scenarios and certain phase-space regions 2) the same BG as in SM Advantages: I) Mass resolution much better from AFP/HPS than Central det. II) Central system produced in a JZ = 0, C-even, P-even state:

• strong suppression of CEP gg→bb background (by (mb/MX)2)
• produced central system is 0++ → just a few events are enough to determine Higgs quantum numbers!

Standard searches need high stat. (φ-angle correlation of jets in VBF of Higgs) and coupling to Vector Bosons III) Information about Yukawa coupling Hbb! Disadvantages: Low signal x-section; affected by Pile-up Low mass CEP Higgs

FP420 R&D Collab., JINST4 (2009) T10001

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Movable beam pipe

• Movable beam pipe (Hamburg beam pipe, MBP) technique used to move the detectors

to and from the beam – in horizontal direction.

• First used at PETRA collider, then proven to be viable at ZEUS (for e-tagger)
• Takes less space than Roman Pots + easy access
• It will host position as well as timing detectors at 220 and 420 m.
• MBP uses standard LHC components (bellows, …), small RF impact
• From LHC point of view, HBP is an instrumented collimator (uses the same motors

but does not go as close to the beam as the collimators) and in fact, it will be

• perated from the LHC CR

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Movable beam pipe

Louvain two-pocket design Torino one-pocket design [D. Dattola, March 2011] Movable beam pipe design needs to be finalized soon – it will go to the tunnel first! Requires involvement of the LHC beam division.

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MBP: Finite Element Analysis

FINITE ELEMENT ANALYSIS OF A 450 mm LONG WINDOW WITH A 3 mm INSIDE CORNER RADIUS

2) 0.25 mm WINDOW THICKNESS

WINDOW DISPLACEMENT

MAXIMUM DISPLACEMENT = 0.286 mm

AFP: University of Alberta HPS: University of Torino

Stainless steel 316 & 304: Study the effect of

• Corner radius on stress into

the corner

• Window length on tensile stress

and max window bow

• Window thickness on max.

stress and window deflection

• Quarter-symmetry segment

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Fast Timing detectors to reduce Pile-up effects

Overlap of 3 events (2xSD+ND dijet) in one BX can fake Higgs signal. Matching measurements in Central vs. Forward detectors reduces the overlap bg significantly. BUT: Due to large cross sections for SD (~20mb) and ND dijets (~μb), additional rejection necessary: REDUCE BY FAST TIMING DET

Huge rates

• f
• f pile

pile-up up pr protons

• tons

Reduced by Fast timing Detectors

JHEP 0710:090,2007 Mhmax scenario, 420+420 mA=120 GeV, tanβ=40 σh→bb=17.9 fb

60 fb-1 at 2x1033cm-2s-1

(significance=3.5σ)

150 fb-1 at 7.5x1033cm-2s-1 plus 150 fb-1 at 1034 cm-2s-1

(significance = 4.5σ)

5 ps

σt = 10 ps →σzvtx = 2.1mm. From proton arrival times: zvtx

central = c(t1 220 – t2 220)/2

Rejection power ~20.

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Fast timing detectors for AFP/HPS

Two types of Cherenkov detectors are employed (both use Microchannel Plate PMTs or Si PMs): High luminosity → high rates, anode currents & collected charge → high demands on MCP-PMT perform. (development pursued in Burle/Photonis) GASTOF: Gas (C4F8) with very fast light pulse (<1ps) -> resolution limited by TTS of MCP-PMTs and electronics (development in UCL Louvain) QUARTIC: two quartic detectors each with 4 rows of 8 fused silica bars (development in Fermilab and UTA Arlington)

• put behind the last Si detector – because of multiple scattering in the fused silica
• fine segmentation -> multi-hit capability
• Designs well advanced
• 10 ps achieved at Test beams!
• ~1ps reference clock system under developm.
• First stage: ~20 ps is OK

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Layout of tracker including beam pipe

This is design for 420m station but very similar design expected for AFP220m.

Geant 4.9.1 simulation: σx ~ 10μm (the same for 4-8 planes)

Physics list: QGSP-EMW Materials: Steel window: 70%Fe, 19%Cr, 10%Ni, 1%Mn, density=8g/cm3, thickness=400μm Si sensor: pure Si, density=2.5g/cm3, thickness=300 μm Electronics board: 90%Kapton, 10%Cu, thickness= 100μm

Plane staggering by half-a-pixel in x Conservative estimate of the distance between the beam center and first sensor: Thin window + Safety offset + Edge + Alignment + 15σbeam (1.5mm) ~ 2.1 mm

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Position detectors

The same requirements for 220 and 420 m regions: Close to the beam => detectors with short edges High lumi operation => radiation hard Silicon detectors Mass resolution of 2-3% => 10-15 μm precision Suppress pile-up => add fast timing det.

220+220: Si det. 1.5 mm and 3.0 mm from beam Reconstruct the central mass from the two tagged protons (from their trajectories and incorporating experim. uncertainties):

Beam energy spread σE= 0.77 GeV Beam spot smearing σx,y = 10 μm Detector x-position resol. σx = 10μm Detector angular resolution = 1, 2 μrad

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Options for Si sensors

Planar Si n-on-n: - used in current ATLAS pixel detector which functions very well

• proven technology, double-side processing,

slim with inactive edge ~250 μm (maybe less!) [ON Semiconductors (Czech rep.) delivered ~50% of all pixel sensors Prague Institute of Physics (PIP) tested ~30% of all pixel sensors] 3D Silicon: - excellent in the small inactive edge and radiation tolerance

• needs only 150 V bias voltage
• proven in test beams, not yet in a real experiment

AFP as well as HPS profit from a close collaboration with existing Central Tracker upgrades (e.g. called IBL [Insertable b-layer] in ATLAS). Obvious synergy: the same time schedule and areas to work on (sensors, RO chips, bump-bonding, module assembly and testing, power supplies, external services, detector control system, off –detector electronics, cooling, …) E.g. AFP is closely watching the IBL decision process about Si sensor type (planar or 3D)

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n-on-n Sensor design

n-implantation to n-type bulk silicon n-on-n sensor – two-side lithography

• Development in Dortmund

MCC services distributed on the chip Slim inactive edge ~ 250μm.

• This may be reduced by modifying guard rings

area and using finer cutting methods Test beams and irradiation:

• Test efficiency of slim sensors close to the edge
• provide inhomogeneous irradiation (highly probable environment for AFP/HPS)

AFP: 4 stations: 6 layers per station -> 24 FE-I4 chips & sensors (~50 with spare) Total number of channels: 24x80x336 = 645120 Thickness = 250 μm Pixel dimensions = 50 x 400 μm Bias voltage = 150 – 600 V Leakage current = 10 – 100 nA/ cm2 Pixel capacitance = ~ 400 fF Expected signal = 19.4 ke- (MPV), 27ke- (mean)

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3D-Silicon

Development motivated by low edge design (Manchester, 3D Collaboration) Advantages:

• Short collection distance (faster collection)
• Low depletion voltage
• Active edge (inactive edge ~ 5 μm)
• High radiation tolerance

Tracker design for AFP420 with 3D-Si

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Read-out chips (AFP)

FE-I3:

• ATLAS pixel det.
• Process: 250 nm IBM CMOS
• Threshold tuning
• Time over threshold 8 bit
• Leakage current compensation

FE-I4:

• ATLAS pixel det. – IBL
• Process: IBM 130 nm
• Largest R/O chip in HE
• Reduced dead space:

FE-I3: 26% → FE-I4:11%

Radiation dose close to the beam at L=1034cm-2s-1 is 1015p/cm2 per year (30 MRAD) AFP: FE-I4 – used for the ATLAS IBL Upgrade. Size similar to the region of interest.

• radiation hard

HPS: PSI46 – used for the CMS Tracker upgrade

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Time schedules

2011: Development of first MBP prototype and of first Si plane prototype. Timing det. electronics full chain with laser. Create Safety committee from AFP & HPS & Vacuum group. 2012: Sensors and chips ready. AFP & HPS recognized as full Upgrade Projects; finalize R&D; Bump-bond chips on sensors. Cooling prototype. Finalize electronics and detector design for timing det. Alignment and support studies. Test beams of full Si det. and Timing det. prototype. Work on TDR. 2013: Approval of AFP by ATLAS & LHCC, Approval of HPS by CMS & LHCC. Construction and testing of full detector unit. 2014: Installation of full AFP220/HPS240 (420 station later) MBP: close cooperation of AFP & HPS & Vacuum group Si det.: cooperation with central tracker upgrade projects Timing detector development Involvement of LHC beam division crucial

• MBP design (urgent): safety review together with beam division, check RF impact
• 3D integration in the tunnel
• Available space in the tunnel or alcove
• BPM electronics: AFP/HPS needs ~10μm precision
• Procurement of standard elements (bellows, motors, BPMS, …)

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Summary

AFP/HPS Physics program: standard diffraction + QCD, Two-photon, anomalous W/Z-γ couplings, Higgsless models and Extra-dimensions Total cost ~ 2M CHF per experiment - a big added value to the ATLAS/CMS Physics programs with a cheap detector Not much space needed: AFP/HPS might use some of existing crates Long 2013-2014 shutdown: install movable beam pipes + Si detector + Timing detector Sensor choice: Si planar or 3D. AFP is closely watching the IBL decision process. Further collaborators are welcome! We urgently need to cover whole areas.

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AFP/HPS Institutes

AFP Institutes: Country HPS Institutes Country University of Alberta Canada Univ. Cath. Louvain Belgium Charles University, Prague Czech rep. INFN Torino Italy Institute of Physics of ASCR, Prague Czech rep. ITEP Moscow Russia IRFU-SPP, CEA Saclay, Paris France Boston University USA Justus-Liebig Universitaet, Giessen Germany Fermilab USA Institute of Nuclear Physics, Cracow Poland Kansas University USA Glasgow University UK Lawrence Livermore NL USA University of Texas at Arlington USA Ohio University USA State University of New York (Stony Brook) USA Rio de Janeiro Brasil After the drastic budget cuts: UK institutes following activities

ATLAS Technical Proposal:

AFP: A Proposal to install Proton Detectors at 220 m around ATLAS to Complement the ATLAS High Luminosity Physics Program (April 2011)

CMS Upgrade R&D Proposal:

R&D of the Detector Systems for Stage One of the High Precision Spectrometer Project (June 2010)

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Box diagram of all services

Cooling under study: thermosiphon or vortex-based dry air cooling. Local station enough to cool down Si det. Only compressed air needed (V. Vacek and his group from CTU Prague).

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