1. RD6 Progress January 2015 TK Hemmick for RD6

2. RD6 Core Program Summary Stony Brook University: CF 4 -based RICH for hadron ID at high momentum (EIC also needs low-p hadron-ID). UV Focal Plane for TPC/HBD hybrid detector. BNL Mini-drift enhancement of planar trackers to improve resolution for inclined tracks. Drift section for TPC/HBD. Yale 3-coordinate pad/strip readout technology. Gas studies for TPC. Hybrid avalanche studies to reduce IBF in TPC. Florida Tech Full-scale forward EIC tracking detector using charge sharing among zigzag strips (lowest channel count) University of Virginia Full scale forward EIC tracking detector using stereo “Compass” readout. (highest resolution)

3. https://wiki.bnl.gov/eic/index.php/Detector_Design_Requirements

4. Summary of RICH Final Results I =12 Photon Yield and Radius scale as expected for Cherenkov Light Easily Distinguished Hadrons to top FNAL Energy

5. Summary of RICH Final Results II Index of Refraction fit matches literature. Peak widths match expectations. Limit to resolution from coarse pads 500  m position resolution more than meets spec. Should be easy with charge division (wrong!).

6. Charge Division Challenges. Charge injection Resistive Layer pads

7. Dynamic Charge Dispersion Simulation (ala ILC): All components have to be convoluted, [[R*L]*A](t)=RLA can be “obtained” analytically [RLA*Q](t) has to be solved numerically (working on). Recent News: TWO students have joined this project! Modeling Dynamic Signal Propagation

8. Fermilab beam test: Minidrift prototype (Chevron Readout)  Compare COMPASS to Chevron Readout COMPASS: 0.4x100mm straight XYStrips Chevron: 2x10mm zigzag pads (good for high multiplicity)  Comparable performance at larger angles Superior to simple centroid resolution at large angles COMPASS vector resolution worsens at small angles due to algorithm used (Fit pulse rise time for each strip to establish charge arrival time) Time slice centroid method used for chevron analysis is optimal at all angles The centroid derived from the chevron readout incorporates an intrinsic differential non-linearity, which was precisely measured in the lab to correct the beam test data. Chevron Readout Measured differential non-linearity used to Correct data

9. TPC/Cherenkov Prototype  In final stages of prototype design  Assembled and tested field cage  Designed and fabricated readout board  Initial field cage drift field simulations (using ANSYS) show <0.1% field distortions Chevron readout Field cage Moveable photosensitive GEM detector

10. TPC Gas Studies Investigate potential TPC gas mixtures with low ion backflow, high drift velocity, and minimal charge attachment losses during charge transport within the gas

11. 3D and Hybrid Gain Studies 3-coordinate readout: Test beam results from 800  m demonstrate 96-117  m . 600  m pitch prototypes exhibit shorts (edge of tech). Hybrid gain stage studies: Combine the advantages of GEMs (stability) and mMEGAs (Ion Back Flow). Piggyback EIC with (challenging) ALICE developments. IBF principle concern of ALICE. E-Resolution principle concern of EIC. Essential characteristics: E-resolution from large gain in the top GEM. IBF worst from top GEM. IBF improves with high E T IBF improves with low E ind 96-117  m

12. Experimental Resolution and IBF

13. Hybrid Avalanche Results I Excellent resolution achieved with little compromise to IBF. Resolution has contribution from primary ionization fluctuations as well! Low IBF a “bonus” as it simplifies design w/o gating grid. Gain sufficient for EIC TPC

14. Hybrid Avalanche Results II 10 8 alpha particle events delivered to varying distributed gain settings. No sparks observed. Reflects lightened burden on  MEGA gain provided by GEM gain. Superior design for future TPCs.

15. Differential Nonlinearitry Correction (Zig-Zag Strips) Motivation: due to large strip width and special structure of the zigzag r/o strips, cluster positions are not anymore accurate if we simply use the Center of Gravity (COG) method. Method: we correct 2-strip and 3-strip clusters’ positions separately using tracking information. We define η ≝ − for each event. is position from normal COG method, max is the strip number on which max. charge is collected. η-dependent response functions are obtained, and corrections are made based on these functions. 2-strip clusters 3-strip clusters 2, 3-strip clusters after correction

16. Improvement of angular resolutions after corrections – HV scan 2-strip clusters, Improved 12-20% after correction 3-strip clusters, Improved 30% after correction Using all clusters, overall resolution reaches < 180 µrad 170µrad

17. Angular resolutions improvement after corrections – position scan Position scan at 3200V in the middle of each sector (1 to 7). Resolution improvement is ~8%

18. Material budget in the beam test DetectorGas gaps [mm] Window mat./thick. [mm] Readout mat./thick. [mm]Rad. len. (%X 0 ) Tracker 13/2/2/2Mylar/~0.1G10/kapton/honeycomb0.32 Tracker 23/2/2/2Mylar/~0.1G10/kapton/honeycomb0.32 SBS 13/2/2/2Al+kaptonG10/kapton/honeycomb0.345 UVA_EIC Mylar/~0.1G10/kapton/Rohacell foam0.42 FIT_EIC3/1/2/1PCB/3.175G10/3.1753.88 FIT_30cm3/2/2/2PCB/3.175G10/2.3623.42 FIT_10cm_13/2/2/2Mylar/~0.1G10/2.3621.5 FIT_10cm_23/2/2/2Hony comb/3.175 G10/2.3621.48 Tracker 33/2/2/2Al+kaptonG10/kapton/honeycomb0.345 Tracker 43/2/2/2Mylar/~0.1G10/kapton/honeycomb0.32 Ar/CO288mm ~0.66 Air~3m ~1 Total rad. L14% X 0 Total material budget is estimated to be 14% X 0. Multiple Coulomb Scattering will add to the real resolutions we get with straight-line track fit. An overall rms of scattering angle is estimated to be 147urad for 32GeV/c particles (eq. 32.15 of Review of Particle 2014). We need to study the MCS in more detail with a Monte Carlo simulation.

19. Beam test geometry implementation in stand-alone Geant4 simulation Physics list used is FTFP_BERT: http://geant4.cern.ch/support/proc_mod_catalog/physics_lists/hadronic/FTFP_BERT.html In which Multiple Scattering model (based on the Lewis theory) is included: http://geant4.cern.ch/G4UsersDocuments/UsersGuides/PhysicsReferenceManual/html/node34.html Beam particles start 20 mm in front of REF1 at X=Y=0, normal incidence on detectors Hits on detectors are recorded from G4 and are not smeared; this allows the study of residuals due only to multiple scattering REF1 REF2 FIT EIC zigzag chamber REF3 REF4

20. All units µm; err not shown Exclusive res._exp Inclusive res._exp Geo. Mean_exp Exclusive res._G4 Inclusive res._G4 Geo. Mean_G4 Corrected resolution 32GeV/c pion case REF1X1644486 2345 73 REF1Y1664587 2445 74 REF2X956679 463239 69 REF2Y976881 473339 71 REF3X825064 332026 59 REF3Y825064 332026 58 REF4X1265583 632741 72 REF4Y1185178 632842 65 MCS-corrected resolutions for trackers and the FITEIC

21. Subgroup task force towards next EIC dedicated forward tracking GEM prototype The task force groups: M. Hohlmann et al. at Florida Tech; N. Liyanage et al. at U. Va. and B. Surrow et al. at Temple U. The three groups are working together towards a ‘universal’ GEM foil design for the next EIC FT prototype, and are pursuing this design to be manufactured by a US company – TechEtch. To have this US company producing GEM foils will benefit the whole community! Mechanical stretching diagram of a GEM chamber (Courtesy of the CMS GEM collaboration) The Florida Tech group will focus on designing the next GEM chamber with mechanical stretching technique, which is successfully used by the CMS Muon upgrade project. Also, our group is going to get all materials designed and to have them sourced by domestic companies. Low mass materials will be considered as many as possible.

22. The dimension of the first ‘universal’ GEM foil designed by the three groups. It has 8 sectors in R direction and 18 sectors in azimuthal direction. HV connections to the sectors will be made at the outer radius. (This is a first aggressive design to let the inner radius go to 8 cm. It’ll be addressed once we know the actual size of beam pipes and interplay with other inner trackers. )

23. An EIC FT disk made from 12 of the ‘universal’ GEM chambers (unit in mm). The 3 cm overlap gives zero dead area within the azimuthal acceptance. Zoom of central region near beam EICRoot Forward Tracker

24. EIC Forward Tracker GEM @ UVa: Design and Construction of Prototype I Goals and key features large 2D triple-GEM prototype for EIC forward tracker detector ever built: 100 cm  (44 cm – 22 cm) Low mass and small dead area full disk chamber Narrow edge GEM frame support and honeycomb for the readout All electronics on inner and outer radius side of the chamber 2D small stereo angle u/v readout on flexible PCB layer Good position resolution and low capacitance noise 24 Pitch = 550  m, Top strips = 140  m, Bottom strips = 490  m 12° 2D u/v readout strips 100 cm 22 cm 44 cm EIC GEM Prototype I

25. Spatial resolution of EIC GEM prototype I: Test Beam Data (FNAL, Oct. 13) Spatial resolution analysis of EIC-GEM prototype I Refine the track fit alignment Precise computation of the x and y offset parameters of the reference trackers Plane rotation of the trackers included in the alignment for the track fit Improvement of the spatial resolution EIC GEM Average resolution in the range of 60 μrad in the radial dial direction Big variation of the resolution in different area of the chamber  pedestal noise variation due to different strip length Resolution of EIC GEM I in cylindrical coordinates Offset correction values for the reference trackers Improvement of the resolution with fine alignment

26. EIC GEM Prototype II: Common GEM foil design with Florida Tech and Temple University 3 areas to investigate with EIC GEM prototype II: Low mass and light detector Reduce overall the material budget Investigate copper less GEM New detector construction technique Possibility to re open the detector to replace parts Use the same chambers for various R&D studies New u/v strips readout design with finer pitch to improve spatial resolution all connectors for FE electronics at the outer radius u/v strips readout board New construction technique: Open chamber Light & low mass detector

27. Summary Excellent progress on all fronts. Results presented here are either submitted or readying for publication. Unified design concepts appearing: Mini-drift universally improves planar tracker performance. Hybrid avalanche gain stage emerging as excellent TPC readout choice. Common geometry forward tracking GEM converging. Common external frame specification emerging. Alternatives still under investigation: HBD option for TPC? Frame design for forward trackers? Tracker cathode style? Photon position for RICH? InstitutionProjectCost (k$) BNLTPC/HBD60 SBURICH30 FITPostdoc + Fwd(chevron)173 UVaFwd(strips)40 YaleHybrid Gain0 TOTAL303 Projected Future Cost

28. Backups

29. Next plans The multiple scattering effect in the FNAL beam test is important and is now preliminarily taken into account by a Geant4 simulation, which gives a final resolution for the zigzag readout of ~167urad. We’ll refine this analysis a little more and submit the first paper on the zigzag GEM to NIM as soon as we can. Finalizing the ‘universal’ GEM foil design by Feb 2015. Then we could send it to TechEtch and CERN engineers for review. After that we could think about to have four GEM foils be produced for each group. It is important to (partially) financially support TechEtch to upgrade the setup so that this company can make 1-m class GEM foils, in the next fiscal year. After the GEM foil design is finalized, we’ll start designing the frames, drift board, etc. for assembling the new GEM chamber. We’ll search for companies to manufacture these stuff. We’ll also design a new zigzag r/o board for the new GEM chamber; the drawbacks on the first zigzag design will be addressed in the new design. We have built a small magnet in the lab which is providing uniform field of 0.98T. We’ll study GEM performances with small chambers in our lab.

30. 32GeV/c pion-beam: Position distributions 30 REF1XREF2X REF3XREF4X FIT_EIC_X Divergence of the ‘beam’ due to MCS is evident.

31. 32 GeV/c pion-beam: MCS Residual distributions for REF1&2 31 REF1X Exclusive REF1X Inclusive REF2X Exclusive REF2X Inclusive Geom. Mean: 45um Geom. Mean: 39um

32. 32 GeV/c pion-beam: MCS Residual distributions for REF3&4 32 REF3X Exclusive REF3X Inclusive REF4X Exclusive REF4X Inclusive Geom. Mean: 26um Geom. Mean: 41um

33. 32 GeV/c pion-beam: MCS Residual distributions for FIT EIC zigzag chamber 33 FITEIC_X Exclusive FITEIC_X Inclusive FITEIC_Y Exclusive FITEIC_Y Inclusive Geom. Mean: 56um