The very forward region Tel-Aviv meeting summary 18 - 19 September, Tel-Aviv, ISRAEL FCAL FCAL Collaboration High precision design Ronen Ingbir ECFA2005

FCAL Collaboration FCAL Goals : design and construction of Luminosity detector Beam monitor Photons calorimeter Goals : design and construction of University of Colorado AGH University, Cracow Institute of Nuclear Physics, Cracow Jagellonian University, Cracow DESY Joint Institute Nuclear Research Dubna Institute HEP Protvino National Center of Particle & HEP Minsk Prague Acad. of Science Tel Aviv University Cooperation with: SLAC Iowa State University Wayne State University FCAL Collaboration High precision design 2 ECFA2005

PhotoCal FCAL Beam diagnostics from beamstrahlung photons Collaboration High precision design 3 ECFA2005

PhotoCal - BS photon analysis Etot=3366.83 TeV Gas calorimeter IP >100m Good energy resolution (10-15%) 21 radiation length : two absorber thickness (1.5, 3.0 mm) of Pb. High intrinsic radiation hardness tails! GPIG simulation + neural network Photon selection: |angle x| > 0.2 mrad |angle y| > 0.1 mrad FCAL Collaboration High precision design 4 ECFA2005

Vertical beam waist variation vert. waist shift > 0 vert. waist shift < 0 FCAL Collaboration High precision design 5 ECFA2005

BeamCal FCAL Detection of electrons/photons at low angle Shielding the inner detector Beam diagnostics from beamstrahlung electrons/positron pairs. FCAL Collaboration High precision design 6 ECFA2005

Beam diagnostics : BS Pairs Observables (examples): total energy first radial moment left/right, up/down, forward/backward asymmetries Solve by matrix inversion (Moore-Penrose Inverse) Beam Parameters Observables 1st order Taylor-Exp. Observables Δ BeamPar Taylor Matrix nom = + * Being tested also for the 20mrad case FCAL Collaboration High precision design 7 ECFA2005

Particle identification in the BeamCal The Physics: SUSY particles production  ~ 102 fb-1 Signature: + - + missing energy The Background: two photons event  ~ 106 fb-1 Signature: + - + missing energy (if electrons are not tagged) Excellent electron identification is needed down to as small angle as possible FCAL Collaboration High precision design 8 ECFA2005

Electron detection in the BeamCal 4 mm 10 mm Nrings 20 Ncells 1660 Nchannels 49800 Nrings 8 Ncells 264 Nchannels 7 920 Low BG ( ~ 0°) High BG ( ~ 90°) 5mm 8mm 10mm Inefficiency to identify Lost particles for R < 55 mm electrons 200 GeV FCAL Collaboration High precision design 9 ECFA2005

Distribution of BeamStrahlung pairs Headon 2 mrad FCAL Collaboration High precision design 10 ECFA2005

20mrad crossing angle and DID field 20 mrad, DID 20 mrad, DID – extended Rmax FCAL Collaboration High precision design 11 ECFA2005

Anti DID FCAL 20 mrad, DID 20 mrad, anti DID Collaboration ECFA2005 12 High precision design 12 ECFA2005

Sampling diamond-tungsten calorimeter Diamond sensors Diamond samples (CVD): - Freiburg (FAP) - GPI (Moscow) - Element6 (De Beers) Sampling diamond-tungsten calorimeter Electric features: 1.Leakage current. 2.Mip & electric field and dose Some sensors show microcracks (and leakage) The CCDs are between 0 and 150 mm Some are stable under irradiation, other not. FCAL Collaboration High precision design 13 ECFA2005

Diamond sensors – test results-1 Element 6 – E6_4p Freiburg, FAP7 l CCD performance of One FAP7 sample is poor, but a signal can still be extracted. Element 6 sample was remetallized and shows good performance. Stable under irradiation FCAL Collaboration High precision design 14 ECFA2005

Diamond sensors – test results-2 Linearity over large dynamic rage CERN PS Hadron beam – 3,5 GeV. fast extraction ~105-107 / ~10ns (Wide range intensities) Freiburg, FAP22 Element 6 Particle flux [mip/(cm2*10ns)] Particle flux [mip/(cm2*10ns)] FCAL Collaboration High precision design 15 ECFA2005

LumiCal Precise measurement of the luminosity by using Bhabha events Extend coverage of the ILC detector FCAL Collaboration High precision design 16 ECFA2005

Polarised Bhabha FCAL Collaboration High precision design 17 ECFA2005

Fast Detector Simulation Motivation : High statistics is required to notice precision of : There is an analytic calculation (and approximation) : Luminosity precision determination : BHWIDE generated properties + smearing to simulate detector FCAL Collaboration High precision design 18 ECFA2005

Data and MC In real life we can include the detector performance (which is measured in test beam) into MC. The only question is: How well should we know the detector performance ? FCAL Collaboration High precision design 19 ECFA2005

Bhabha selection cuts L R FCAL In Eout-Ein P= Eout+Ein Out 3 cylinders Collaboration High precision design 20 ECFA2005

Present Understanding (pad option) Based on optimizing theta measurement 10 cylinders (θ) 60 cylinders (θ) 14 Cylinders (mrad) 11 layers (z) 15 layers (z) 4 layers (z) FCAL Collaboration High precision design 21 ECFA2005

Strip design FCAL Every other ring: 64 cylinders 120 sectors 30 rings Collaboration High precision design 22 ECFA2005

Performance of present configurations Strip Performance Pad Performance Parameter 8:16% 25% Energy resolution 3.3 * 10-5 rad 3.5 * 10-5 rad resolution 10-3 rad 10-2 rad ~2.9* 10-6 rad ~ 1.5 * 10-6 rad 3720 (with bonding sectors) 13,320 (without bonding) 25,200 Electronics channels With this performance the goal can be reached. FCAL Collaboration High precision design 23 ECFA2005

FCAL Two photon events Collaboration ECFA2005 Energy [GeV] LUMICAL BEAMCAL Polar angle [deg.] Independent generator studies (WHIZARD, Vermasseren) have shown that physics background from the four-lepton processes is present in the Luminosity Calorimeter with an average rate of 10-3 tracks per bunch crossing for head-on collisions. Further studies for crossing angles is under way. FCAL Collaboration High precision design 24 ECFA2005

FCAL Collaboration ECFA2005 Lumical is positioned on detector axis Lumical is centered around the outgoing beam FCAL Collaboration High precision design 25 ECFA2005

X- angle background FCAL Beamstrahlung pair background Collaboration 250 GeV FCAL Collaboration High precision design 26 ECFA2005

FCAL Systematic effects: radial beam offset and LumiCal tilt y y dr x Similar behaviour for 20 mrad and 2 mrad when LumiCal is centered around the outgoing beam. up to three orders of magnitude change when LumiCal is centered around the 'detector axis'. x y x y dr FCAL Collaboration High precision design 27 ECFA2005

Electronics FCAL Collaboration ECFA2005 Readout electronics: facing the challenges: - 5 bunch trains per second (5 Hz) - 3000 bunches within one train - One bunch every 300ns, 150ns possible - Each bunch to be registered - High dynamic range (better 1:10k) - More than 10k channels, depending on design - Fast, low power, radiation hardness to be considered Next Steps: - Investigation of preamp principles - Feasibility studies of digitization Investigation of known systems Pads for wire bonding should be at least 60 µm x 60 µm Width of traces can be small as 1 µm, but the impedance will be high Grounded lines between signal traces will reduce the crosstalk FCAL Collaboration High precision design 28 ECFA2005

Effective wafer size – more detector tiles Mechanical design and production constrains Segmented silicon sensors interspersed into the tungsten half disks Two half barrels to allow for mounting on closed beam pipe The blue bolts support the heavy part of the detector, tungsten half disks The red bolts carry only the sensors Holes for precision survey the sensors position Guardring reduces the active sensor surface by ~1 mm on each side of a tile Effective wafer size – more detector tiles FCAL Collaboration High precision design 29 ECFA2005

FCAL Detector Position XYZ displacement mesurement with two beams BW camera DX1-1394a from Kappa company 640 x 480 with Sony ICX424AL sensor 7.4 μm x 7.4 μm unit cell size Laser module LDM635/1LT from Roithner Lasertechnik ThorLabs ½” travel translation stage MT3 with micrometers (smallest div. 10 μm) Neutral density filters ND2 Two laser beams (one not perpendicular to the sensor) allow us to measure XYZ translation in one sensor FCAL Collaboration High precision design 30 ECFA2005

Summary FCAL Collaboration High precision design 31 ECFA2005

Head-on design FCAL LumiCal BeamCal Collaboration ECFA2005 Overlap region LumiCal rmin=8 cm rmax=28 cm BeamCal rmin=1.5 cm rmax=10 cm Beam hole FCAL Collaboration High precision design 32 ECFA2005

(Reasonable Statistics) X- angle design (step 1) LumiCal rmin=13 cm rmax=28 cm (Reasonable Statistics) BeamCal rmin=2 cm rmax=16 cm Beam hole FCAL Collaboration High precision design 33 ECFA2005

X- angle design (step-2) Detectors are centered around the outgoing beam BeamCal + 30o blind area (incoming beam) FCAL Collaboration High precision design 34 ECFA2005

More detailed information can be found at the collaboration web page : FCAL Collaboration High precision design Thank you ! You are invited to the more focused talks given by our collaboration in this meeting More detailed information can be found at the collaboration web page : http://www.ifh.de/ILC/fcal FCAL Collaboration High precision design 35 ECFA2005