MDI Overview Hitoshi Yamamoto Tohoku University GDE/LCWS06, Bangalore, March 9, 2006

MDI Panel ■ Members ◆ LEP panel (Luminosity, Energy, Polarization) Wolfgang Lohmann, Tsunehiko Omori, Eric Torrence ◆ GDE Philip Bambade, Witold Kozanecki, Tom Markiewicz, Andei Seryi, HY (chair) ◆ Detector concepts Phil Burrows, Karstern Buesser, Toshiaki Tauchi (+...) ■ Charge ◆ (In short) Maintain oversight of IR/MDI issues that are relevant both to accelerator and detectors and report to WWS and GDE Area Group. Organize joint MDI sessions. Formed Dec by WWS and GDE

MDI Sessions (GDE+WWS) ■ Friday 10th, 11am-12:30pm (J.N. Tata) ◆ MDI issues - A. Seryi ◆ IR designs by detector concepts GLD IR design - Toshiaki. Tauchi LDC IR design - Karsten Buesser SiD IR design - Phil Burrows Discussion ■ Saturday 11th, 10am-11:30am (J.N. Tata) (over the coffee break) ◆ 1 IR vs 2 IR Introduction by Tom. Markiewicz + Discussion ◆ Detector backgrounds Introduction by Karsten. Buesser + Discussion ◆ MDI for gamma-gamma Introduction by Klauss. Moenig + Discussion Goal : communication between acc. and det.

MDI Sessions (WWS) ■ Sunday 12th, 9am-10:30pm (J.N. Tata) End station A R&D program Energy spectrometry (End station A) Fast and precise Luminosity measurement Systematic limitations to luminosity BeamCal Veto performance Physics Data for Detector Calibration ■ Sunday 12th, 2pm-4pm (J.N. Tata) The ATF laser wire system Laser requirements Stimulated Breit-Wheeler process as a source of pairs Power losses in the 20 mrad extraction line at 1 TeV Energy depositions in the extraction line First estimate of backgrounds reflected at... Final doublet layouts and power densities The stabilisation of final focus (StaFF) system Study on Low-Energy Positron Polarimetry Polarized positron source (E166)

1 IR vs 2 IR ■ 2 IR 2 detectors : 2 mrad/20 mard ◆ 2 IR’s shifted longitudinally by ~140m, tranversely ~20m 2 IR halls (baseline) ◆ One long hall to contain 2 IR and 2 detectors (alternative)

■ 1 IR : may be~14 mrad xing ◆ 1 detector : simple ◆ 2 detectors : means push-pull Switchover time ~ 1 day, Frequency ~ every 3month So that luminosity in one ‘in’ does not generate physics (1 day to find Higgs? - at design lum.) Shielding - self shielding (‘PACMAN’) → No shielding wall. Floor motion ~ a few mm. → Wall and floor to be independent. Final quads attached to detector. SC solenoid may stay cool. → MDI sesssion(3/11 10am), A. Seryi’ s GDE talk (3/9 17:30)

Energy Measurement ■ Goal: ◆ 100ppm (10 -4 ) absolute energy measurement ■ Baseline: ◆ 1 upstream + 1 downstream spectrometers / beam ◆ Upstream spectrometer 4-magnet chicane + RF BPMs 1mm offset +  100nm:10 -4 ◆ Downstream spectrometer 3-magnet chicane w/wigglers + SR photon detectors BPM Wiggler SR detector

20mrad xing extraction line diagnostics SR detectors Wigglers Polarimeter Energy chicane Compton detector Z0Z0 250 GeV Compton IP

2mrad xing extraction line disgnostics Plan view Side view wigglers SR detectors Energy chicane Polarimeter Compton detector

Energy Measurement R&Ds ■ Upstream spectrometer Calibration and operation precedure RF BPM design (better than 100nm accuracy) BPM tests : ATF (nBPM program), SLAC ESA. ■ Downstream spectrometer Detailed simulation (realistic magntic fields, backgrounds) Design, evaluation of wiggler magnets. SR detector (quartz fiber) readout test. ■ Full scale prototypes ◆ Both BPM-based and SR-based, at SLAC ESA

Polarization Measurement ■ Goal : ◆ 0.25% accuracy (particularly on Z) ■ Baseline : ◆ 1 upstream + 1 downstrem polarimeters / beam ◆ Compton polarimeter Shoot circularly-polarized photon at the electron beam at a focus. Measure the compton-scattered electron. Polarization vector at IP = that at the polarimeter → beam direction at IP parallel to that at the polarimeter 4-magnet chicane

Luminosity Measurement ■ Accuracy goal : or better absolute ■ Detector : LUMCAL(LUMMON/FCAL) ◆ ~30-90 mrad ◆ ~10 Bhabhas/train ◆ Default : Si-W calorimeter ■ R&Ds The precision achievable for different xing angles? Careful systematics studies desirable for Giga-Z, larger polar angles? Backgrounds from pairs etc.? ■ ‘Physics’ events (central detector) : ◆ Acollinear Bhabha → Luminosity spectrum etc.

LDC IR configration (2mrad xing) GLD IR configration (2mrad xing)

20 mrad 2 mrad 4 m 26 cm 2 m 20 cm BeamCal SiD IR configuration

B e+ e- outgoing incoming slow e- : along B fast e- : along beam Pairs K. Buesser e+ kicked up/down : contains beam profile info. Larger xing angle → larger bkg. (e+ ⇔ e- for the other side of IP) 20 mrad xing

Pairs-Region Detectors ■ 5~30 mrad ■ pairs/bunch ■ BEAMCAL (BCAL) ◆ Fine-segmented Diamond-W ◆ Fast luminosity/beam profile feedback ◆ Also used to reject 2-photon bkg in SUSY pair prodction. ■ Pair monitor ◆ Single-layer silicon (less radiation) ◆ Slow luminosity/beam profile feedback ■ R&Ds ◆ Electron tagging (BEAMCAL) ◆ Prototyping ◆ Beam profile : work for large xing angles? ◆ Fast feedback for Si pair monitor

DID (Detector-Integrated Dipole) ■ Xing angle (w/o correction) ◆ beam sees B transeverse of solenoid → spiral ◆ Still head-on (mod xing angle) ? Yes for e+e-. No for e-e-. Problems still for e+e- : SR emittance growth (significant in some cases) Polarization vector rotation (minor problem?) e+e-B e+e- e-e-

DID and anti-DID ■ Align B with incoming e+/e- beams (on av.) : DID ◆ Solves SR emittance growth. ◆ ×2 Bt for outgoing beams → Worse pair background ■ Align B with outgoing e+/e- beams (on av.) : antiDID ◆ Pair background ~ 0mrad xing angle. ◆ ×2 Bt for incoming beams → Worse for SR emittance growth ~OK for 14 mrad, tight for 20mrad. e+e- BB e+e- BB DID or antiDID, not both simultaneouly

Detector Backgrounds ■ Pairs ◆ Direct : Important particularly for vertexing ◆ Indirect : backscattering to TPC ◆ DID or anti-DID or neither? ■ Muons ◆ Upstream muon spoiler ◆ Iron shielding on beampipe ■ Neutrons ■ 2-photon hadrons, radiative Bhabhas ■ Disrupted beam, beam halo, SR ■ What are detector telerances? → MDI session 3/11 ~10:30am

BDS for gamma-gamma ■ At least ~25mrad xing needed. ◆ Upgrade from 20mrad (14mrad also possible) ◆ 1.8m shift for detector + new tunnels for dumps. → 3/11 11am gamma-gamma MDI session, A. Seryi’s BDS (GDE) talk (3/9 17:30)

No Summary Please attend the sessions/talks and participate in discussions

Polarimeter (upstream)

Polarization Measurement R&Ds ■ Extraction-line polarimeter Backgrounds due to SR, disrupted beam, beamstrahlung, radiative Bhabas. Sensitivities to misalignments of spin vector, collision offsets. Compatibility with energy spectrometer. Sensitivities to crossing angles and DID. Detailed designs of Compton laser, IP and detector. ◆ Alternative laser : Fabry-Perot cavity