E.C. Aschenauer for the group

 Optimize the IR design to be able to integrate  the luminosity monitor  the lepton polarimeter  the low Q 2 -tagger  Develop a Monte Carlo code for Bremsstrahlung (wide and collinear emission) taking into account the polarization dependence of the bremsstrahlungs cross section  study impact on relative luminosity and how accurate polarization needs to be known  Integrate a first layout in the EICRoot simulation package  develop a dedicated e-polarimeter simulation package  Determine the detector performance requirements based on physics and machine backgrounds  Follow up with targeted detector R&D, which fulfills the determined requirements  Postdoc hired: starting mid of August 2014 E.C. Aschenauer EIC R&D Meeting January

by Stephen Brooks E.C. Aschenauer 3 EIC R&D Meeting January 2015  space constraints need to be taken into account in detector, e- polarimeter, lumi-monitor and tagger design design IR-8 hall IP FFAG lattice  The bypass is 2.40m outside the current RHIC IP.  The detector centre line is 2.10m inside the current RHIC IP. RHIC IP.  Relative spacing is 4.5m.

E.C. Aschenauer EIC R&D Meeting January e-Beam Hadrons synrad Matching  16 mrad bends “D0” Cryostat Cryostat CryostatCryostat Cryostat Cryostat Plan View of IR Layout 10 mrad crossing DetectorRegion(e-beamaligned) Philosophy: detect forward particles in the warm section between the IR magnets and Crab Cavities ZDC RomanPots Design: compromises physics and machine requirements low Q 2 tagger (not to scale)

E.C. Aschenauer EIC R&D Meeting January 2015  Directly import CAD files  Import magnetic field maps  Implement Roman Pots, ZDC, low-Q 2 tagger, Lumi Monitor, Electron Polarimeter Goals: 5 ROOT event display hadron-going side beam line elements

E.C. Aschenauer EIC R&D Meeting January  main detector;    <-5 : scattered lepton needs to be detected in dedicated low-Q 2 tagger  kinematic coverage in Q 2 -x-  critical for physics scattered lepton more and more at -  lepton beam energy theta (rad)

E.C. Aschenauer EIC R&D Meeting January Extended IR region and by pass modeled in Geant low Q 2 -tagger RP e-polarimeterand luminosity detector are next to be integrated in IR-design and modeled in Geant

 Compact detector system comprising of:  2 tracking layers -> reconstruct θ o each layer consists of a 6x4 array of 5cm 2 cells and 400um thick  Ecal -> reconstruct E Ecal trackinglayers 20 cm 30cm -15m -12m -4m 0m -15m -12m -4m 0m electrons side view E.C. Aschenauer EIC R&D Meeting January

electrons side view top view E.C. Aschenauer EIC R&D Meeting January  The acceptance of low scattering angle electrons is limited by:  Size of beampipe  magnet apertures in quads and dipoles o we can do something about this fairly easily o currently communicating with Brett Parker of CAD o see IR schematic on next slides

 electron beam line passes through the yoke common to the hadron triplet  4.5 – 5.2cm radial aperture for electron beams  meant to increase experimental acceptance  current v2.1 design has electron aperture parallel to hadron beam (and aperture)  electron beam crosses at an angle of 10mrad  this limits the acceptance and we can do better  will show rotating the orientation of the aperture can increase acceptance E.C. Aschenauer EIC R&D Meeting January

nominal design 20 mrad rotation (+10cm shift in x) 30 mrad (+10cm in x) electrons E.C. Aschenauer EIC R&D Meeting January

-0.5 <  < 0 rad -0.5 <  < 0 rad 0 <  < 0.5 rad 0 <  < 0.5 rad -5 < θ < -4 mrad -5 < θ < -4 mrad -4 < θ < -3 mrad -4 < θ < -3 mrad -3 < θ < -2 mrad -3 < θ < -2 mrad -2 < θ < -1 mrad -2 < θ < -1 mrad -1 < θ < 0 mrad -1 < θ < 0 mrad 0 < θ < 1 mrad 0 < θ < 1 mrad Note: θ is relative to electron beam y [cm] x [cm] y [cm] E.C. Aschenauer EIC R&D Meeting January

E.C. Aschenauer EIC R&D Meeting January

-6 < θ < -5 mrad -6 < θ < -5 mrad -5 < θ < -4 mrad -5 < θ < -4 mrad -4 < θ < -3 mrad -4 < θ < -3 mrad -3 < θ < -2 mrad -3 < θ < -2 mrad -2 < θ < -1 mrad -2 < θ < -1 mrad -1 < θ < 0 mrad -1 < θ < 0 mrad 0 < θ < 1 mrad 0 < θ < 1 mrad nominal design rotate final bore rotate all bores x [cm] y [cm] x [cm] y [cm] x [cm] y [cm] E.C. Aschenauer EIC R&D Meeting January

 Add a layer of digitization accounting for segmentation of sensor pixels  Implement a realistic Ecal response for energy reconstruction  Fold both these effects into the θ resolution as well as Q 2 resolution  Implement a full beam pipe to observe the effect  One thing to check: simulation is done with only the electron beam installed, will results be different if both beams are installed simultaneously?  Improve scattering angle reconstruction code further E.C. Aschenauer EIC R&D Meeting January

16 Large Rapidiy Gap method o M X system and e’ measured o Proton dissociation background o High acceptance in  for detector two methods: to select events Need for HCal in the forward region E.C. Aschenauer EIC R&D Meeting January 2015 Cuts: Q 2 >1 GeV, GeV, 0.01<y<0.85 DVCS – photon kinematics: proton/neutron tag method o Measurement of t o Free of p-diss background o Higher M X range o to have high acceptance for Roman Pots / ZDC challenging Roman Pots / ZDC challenging  IR design  IR design Need for Roman Pots (RP) and Zero Degree Calorimeter (ZDC) detector acceptance:  >4.5 increasing Hadron Beam Energy: influences max. photon energy at fixed  photons are boosted to negative rapidities (lepton direction)

 revisit acceptance studies with the newest IR design in EicROOT  very simple detector design for this purpose  single large tracking sensor  placed at z = 18m  place 10 σ distance from beam (1.2cm at 18m)  only placed on one side of the beam o will not fit on other side b/c of electron beam o but could cover directly above and below beam  particle simulation  simulate single particles (not full DVCS events)  throw flat in p, θ, φ, but weight  realistic θ  include 20% energy loss of proton (which is distributed flat) E.C. Aschenauer EIC R&D Meeting January

E.C. Aschenauer EIC R&D Meeting January 2015  possibly gain with a station very far down (>40m)  still need to look into this  seems to be lost in magnet yoke (see next slide)  can work with CAD to improve 18

 generate 100 protons in the range in the range 240 < p < 250 GeV/c 240 < p < 250 GeV/c and 4.5 < θ < 5 mrad and 4.5 < θ < 5 mrad  many tracks hit magnet yoke in the first yoke in the first quad magnet quad magnet  a handful still make it through  need to rotate magnets as in the lepton as in the lepton direction direction z E.C. Aschenauer EIC R&D Meeting January

 Optimize the IR design to be able to integrate  the luminosity monitor  the lepton polarimeter  the low Q 2 -tagger  added Roman Pot system in hadron beam direction to the study list  Develop a Monte Carlo code for Bremsstrahlung (wide and collinear emission) taking into account the polarization dependence of the bremsstrahlungs cross section  study impact on relative luminosity and how accurate polarization needs to be known  Integrate a first layout in the EICRoot simulation package  develop a dedicated e-polarimeter simulation package o next step  Determine the detector performance requirements based on physics and machine backgrounds  Follow up with targeted detector R&D, which fulfills the determined requirements E.C. Aschenauer EIC R&D Meeting January

E.C. Aschenauer EIC R&D Meeting January BACKUP

E.C. Aschenauer EIC R&D Meeting January 2015  Optimize the IR design to be able to integrate  the luminosity monitor  the lepton polarimeter  the low Q 2 -tagger  Develop a Monte Carlo code for Bremsstrahlung (wide and collinear emission) taking into account the polarization dependence of the bremsstrahlungs cross section  study impact on relative luminosity and how accurate polarization needs to be known  Determine the detector performance requirements based on physics and machine backgrounds  Integrate a first layout in the EICRoot simulation package  develop a dedicated e-polarimeter simulation package  Follow up with targeted detector R&D, which fulfills the determined requirements Request: Money for one PostDoc for 2 years  PostDoc starts 11 th of August 22

E.C. Aschenauer 23 Summarized at: Hadron Beam: 1.the detection of neutrons of nuclear break up in the outgoing hadron beam direction  location/acceptance of ZDC 2.the detection of the scattered protons from exclusive and diffractive reaction in the outgoing proton beam direction the detection of the spectator protons from 3 He and Deuterium the detection of the spectator protons from 3 He and Deuterium  location/acceptance of RP;  potential impact of crab-cavities on forward scattered protons 3.local hadron polarimeter  CNI polarimeter Lepton Beam: 4.the beam element free region around the IR 5.minimize impact of detector magnetic field on lepton beam  synchrotron radiation  synchrotron radiation 5.space for low Q 2 scattered lepton detection 6.space for the luminosity monitor in the outgoing lepton beam direction 7.space for lepton polarimetry Important EIC is a high luminosity machine > cm -2 s -1 such controlling systematics becomes crucial  luminosity measurement  lepton and hadron polarization measurement  control of polarization direction EIC R&D Meeting January 2015

E.C. Aschenauer EIC R&D Meeting January “ZDC” MDI Treaty 4.5 m Q0 Q1 B1 Q2 Neutrons p = p o p = 80%p o p = 50%p o protons from Au decay IR design integrated in Detector MC framework: Direct import of CAD files Direct import of CAD files Geometry Geometry Material tags Material tags Direct import of.madx field info files Direct import of.madx field info files Detectors: Roman pots, ZDC, Lumi monitor, Detectors: Roman pots, ZDC, Lumi monitor, e-Polarimeter e-Polarimeter

detector acceptance:  >4.5 E.C. Aschenauer EIC R&D Meeting January x250 Generated + Quad aperture RP (at 20m) accepted  t (~p t 2 ) reach influences b T uncertainty t min ~ GeV 2  300 GeV 2  f/f > 50% t min ~ GeV 2  300 GeV 2  f/f > 50%  beam cooling critical to achieve high low t (p t ) acceptance with Roman Pots low t (p t ) acceptance with Roman Pots  add cerenkov counters to identify heavy products with same A/Z  LHCf products with same A/Z  LHCf simulated simulated + Quad-acceptance Quad-acceptance + 10  BC clearance RP performance:  RP performance assumptions very conservative following STAR RP   P/P 1% & angular resolution < 100  rad

E.C. Aschenauer 26   Momentum smearing mainly due to Fermi motion + Lorentz boost   Angle 99.9%) after IR magnets at 20m  after IR magnets  RP acceptance +10  beam clearance +10  beam clearance  90% tagging efficiency EIC R&D Meeting January 2015

E.C. Aschenauer 27 Results from GEMINI++ for 50 GeV Au +/-5mrad acceptance seems sufficient EIC R&D Meeting January 2015 Important: For coherent VM-production rejection power For coherent VM-production rejection power of incoherent needed up to 10 4 of incoherent needed up to 10 4  ZDC detection efficiency is critical  ZDC detection efficiency is critical Can we reconstruct the eA collision geometry: details: talk by L. Zheng

E.C. Aschenauer EIC R&D Meeting January E crit < 35 keV for 21.2 GeV electrons 2.3mrad 3.1mrad 4.6 mrad photonbeamline

E.C. Aschenauer 29 EIC R&D Meeting January 2015 Bremsstrahlung ep  e  p: Bethe-Heitler (collinear emission):  very high rate of ‘zero angle’ photons and electrons, but  sensitive to the details of beam optics at IP requires precise knowledge of geometrical acceptance requires precise knowledge of geometrical acceptance  suffers from synchrotron radiation  sperature limitation  pile-up QED Compton (wide angle bremsstrahlung):  lower rate, but  stable and well known acceptance of central detector  Methods are complementary, different systematics NC DIS:  in (x,Q 2 ) range where F 2 is known to O(1%)  for relative normalization and mid-term yield control BeAST HERA Concept:  normally only  is measured  Hera: reached 1-2% systematic uncertainty

EIC R&D Meeting January 2015  Concept: Use Bremsstrahlung ep  ep  as reference cross section  different methods: Bethe Heitler, QED Compton, Pair Production  eRHIC BUTs:  with cm -2 s -1 one gets on average of 23 bremsstrahlungs photons/bunch for proton beam  A-beam Z 2 -dependence  this will challenge single photon measurement under 0 o  coupling between polarization measurement uncertainty and uncertainty achievable for lumi-measurement  no experience no polarized ep collider jet  have started to calculate a with the help of Vladimir Makarenk  hopefully a is small E.C. Aschenauer 30 Goals for Luminosity Measurement:  Integrated luminosity with precision δL< 1%  Measurement of relative luminosity: physics-asymmetry/10  Fast beam monitoring for optimization of ep-collisions and control of mid-term variations of instantaneous luminosity Impact on method of luminosity measurement Impact on method of luminosity measurement requires ‘alternative’ methods for different goals requires ‘alternative’ methods for different goals

 zero degree calorimeter  high rate  measured energy proportional to # photons  subject to synchrotron radiation  alternative pair spectrometer 31 VacuumChamber L3L3L3L3  e + /e -  e-e-e-e- e+e+e+e+ Dipole Magnet very thin Converter L2L2L2L2 L1L1L1L1 SegmentedECal   The calorimeters are outside of the primary synchrotron radiation fan   The exit window conversion fraction reduces the overall rate   The spectrometer geometry imposes a low energy cutoff in the photon spectrum, which depends on the magnitude of the dipole field and the transverse location of the calorimeters E.C. Aschenauer EIC R&D Meeting January 2015