Ozgur AtesHampton University

HUGS 2009-JLAB

TREK Experiment“Tracking and Baseline

Design”

Secondary lines for +, K+, or p beam

50 GeV/c proton beam to primary production target

Secondary lines for -, K-, or p beam

The Hadron Hall at J-PARC

Time Reversal violation Experiment with Kaons:

Search for New Physics beyond the Standard Model by Measurement of T-violating

Transverse Muon Polarization in K+ μ+π0 νμ Decays

New official website:

http://trek.kek.jp

• Planar GEMs “C1” between CsI and C2, or in replacement of C2

• Cylindrical device “C0” in replacement of C1

C1: Planar GEMs for TREK

•“C1” To cover CsI gaps on the outside

Target and Tracking

Better kinematical resolution

Addition of C0 and C1 GEM chambers with- high position resolution - higher rate performance Larger C3-C4

distance

Use of He bags

New target

E246 J-PARC

Upgraded Trek Detector Apparatus

Geant4 Simulation

9

Geant4 studies initiated in Summer 2008

GOALS:

Realistic geometry of upgraded TREK apparatusRealistic tracking performance

Obtain design criteria for

Sizes and locations of new elementsAngular and spatial resolution of tracks at detector elementsWhich spatial detector resolution is adequate?Optimization of material budget

Got started with

Geometry of target (from Steffen/Eric) + C0 + C1 + C2, coded materials

Full cylinders of target and C0 but only one of 12 sectors for C1,C2

Generate monoenergetic 100 MeV muons uniformly distributed over volume of target with opening angle according to muon gap size.

Produce hits in detector elements of C0, C1, C2

Use multiple scattering or physics off Record hits along track and write set of

variables (th, ph, z, y, p, edep. mom, etc.) to ROOT TREE

Geant4 Simulation

Root Analyses

• Studied acceptance of tracks in C0, C1, C2.

•From this study, determined required geometric sizes of C0 and C1.

•Found out that;

•Length of C0 should be: 300 mm•Width of C1 should be: 200 mm•Length of C1 should be: 480 mm

Determination of Length of C0

Determination of Width of C1

Determination of Length of C1

Straight-Line Fit in 3D

• Recorded hit locations of Readout layers of C0, C1 and C2. •Applied straight-line fit in 3D for each generated event.

•Reconstruct straight track from recorded hits with 3D straight-line fit•Recorded fit parameters for each track, and locations of fitted track at each 3 readout layers.

•Closest distance of reconstructed track to origin of generated track (vertex difference)(1st column)•Difference of generated hit position at detectors(C0,C1,C2) and that of the recons. track (2nd to 4th column)

RESIDUALS

Systematic Study of Resolution

Backup Slides•Sanity check: Residuals for Phys=OFF and perfect detectors

•Intrinsic tracking resolution: Explicit Gaussian smearing of hits

•Study effect of physics (MS, Bremss., Ionization, Pairprod. ) separately from intrinsic resolution, use balancing as criterion for design resolution

•studied residuals, i.e. difference of generated and reconstructed hit locations at each readout layer, and at target vertex (closest point with respect to generated vertex)

•studied residuals with and without physics activated in Geant4 (multiple scattering and energy loss)

•concluded lower limits the required intrinsic resolution (<<residual)

High Rate Chamber – Gas Electron Multiplier (GEM) Still Gas Ionization and Avalanche, again, but… A different way to get an intense electric field, Without dealing with fragile tiny wires, and Release + ions much faster

-V

~400v0.002”

GEM

To computer http://gdd.web.cern.ch/GDD/