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Status report on ongoing work related to ECAL Design and Scintillator/W/Silicon Hybrid

Status report on ongoing work related to ECAL Design and Scintillator/W/Silicon Hybrid. Several topics : E-flow study Photon reconstruction ECAL design studies Photon/pion separation

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Status report on ongoing work related to ECAL Design and Scintillator/W/Silicon Hybrid

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  1. Status report on ongoing work related to ECAL Design and Scintillator/W/Silicon Hybrid Several topics : E-flow study Photon reconstruction ECAL design studies Photon/pion separation test setup hermeticity study Graham W. Wilson Univ. of Kansas July 29th 2004

  2. E-flow study: influence of intrinsic resolution Write up nearly finished. See http://heplx3.phsx.ku.edu/~darius/eflow/eflow.pdf presented at Cornell July 03. With Darius Gallagher (grad. student) Graham W. Wilson

  3. Photon reconstruction • Carsten Hensel (based at FNAL) has started working on photon reconstruction issues (some) pertaining to p-flow with Steve, Steve (Argonne) and in collaboration with Norman and Ron (SLAC) • ANL workshop very helpful • Results should be reported at a future meeting. • Will be needed to really address whether the hybrid technique pays off for the physics. • LCS developments towards flexible geometry, LCIO, look encouraging for studies of detector design choices Graham W. Wilson

  4. Three strawman hybrid designs Studied with GEANT4 (range cut = 0.1 mm) A super-layer (SL) Sc-W-Sc-W-Si-W-Sc-W-Sc-W HY75 (15 SL) HY135 (15 SL) HY42 (14 SL) In each case the Si layer is chosen as 400 mm Si + 2.0 mm G10 as in SDMar01 detector So far: study uniform sampling structures. Graham W. Wilson

  5. Energy resolution for sampling W calorimeters 42 layers = 2.5 mm W 56 layers = 1.75 mm W 75 layers = 1.4 mm W 135 layers = 0.78 mm W Photons Cost issues: W cost  independent of thickness if rolled ? Si and scintillator scale as area, and can be more expensive if thinner. GWW Also plotted, CALICE, Asian, LCCAL, PbWO4 Graham W. Wilson

  6. Compactness Upper curves, 1mm gap CALICE Pb WO4 Lower curves, no gap Also plotted: Asian, LCCAL(Pb) Need to minimise gaps, reduce space needed for fiber routing, by sharing fiber routing gaps among layers Assume 25% of scintillator thickness used for readout Graham W. Wilson

  7. Photon/pion separation studies • Work in progress to look at simulation of hadronic showers in various ECAL designs • Substantial work on photon position resolution. • Interested in exploiting timing info to disentangle photons from hadronic shower interaction products. Graham W. Wilson

  8. HY42 design (RM=16 mm) 1 GeV photons 50 mm 16 mm Pixel size 5 mm 1 mm yrec-ytrue (mm) Graham W. Wilson ytrue (mm)

  9. Superb Position Resolution for 1 GeV Photons For illustration purposes only !: Si-W, 42 layers, 1mm x 1mm pixels, RM = 13.5 mm First 10/7 X0 330 mm First 15/7 X0 380 mm 1 GeV photons Transverse segmentations much finer than 5 mm may be useful – Si strips ? Integrated 1500 mm Graham W. Wilson Position residual (mm)

  10. Hybrid design issues • Work in progress on “staggering” of Si layers and investigation of rectangular pixel geometries. • Planning to study novel scintillator media (eg. lead-loaded) Graham W. Wilson

  11. What scintillator transverse granularity makes sense ? I suspect that for Scint/W solution, tile size needs to be < 30 mm. (50 mm is too big). For Si/W/Scint. hybrid – not obvious. Perhaps 50 mm or larger is OK. Needs algorithm development. What thickness makes sense ? Thin scintillators get more expensive per unit area not cheaper ! 2 mm ? 1.5 mm ? 1.0 mm ? Thinking of starting with 50*50*5 mm to gain experience. Move on to 30*30*2 What to test ? Graham W. Wilson

  12. VME DAQ from scratch Using LabView 8 2” PMTs with help from K-State. 1st QDC & TDC measurements mid-Jan. 04 Planning flexible testing capabilities of various scintillator/fiber geometries for light-yield, uniformity, time resolution. test setup: cosmics, sources Nov 9th, 2003 V812 CFD (16 ch) V775 TDC (32 ch) (35ps LSB 12-bit) V792N QDC (16 ch) (100fC LSB 12-bit) Graham W. Wilson

  13. Cosmic test DAQ development • Commissioned by Eric Benavidez (undergrad.) • Jonathan van Eenwyk – very promising undergrad. , working since March. • Both working on developments • Now have fairly flexible interface for CFD control, TDC DAQ, QDC DAQ, online histogramming (all using LabView) • Infrastructure : HV, cables, discriminators etc. Graham W. Wilson

  14. QDC spectra COSMICS 1500 V Pedestal subtracted QDC spectra for each scintillator. 1 cm thick scintillator paddles. Fit is a Landau distribution. TOP BOTTOM Graham W. Wilson

  15. Source studies • Recently, acquisition of various sources for tests of thin scintillators. • Internal conversion sources with thin mylar windows. In particular Bi-207 and covering range 100 keV to 1 MeV. • GEANT4 studies suggest that complete absorption is fairly frequent. • Delta-function energy deposit rather than β-spectrum or Landau distribution. Graham W. Wilson

  16. Bi-207. 1047 keV e-. 2.5mm Scint. Total absorption Landau part 5mm air Deposited energy fraction Graham W. Wilson

  17. Forward hermeticity study √s=500, m_smu=225,DM=10.3 (GeV) • Darius Gallagher (grad. student) and I have been working on a study of two-photon eemm(g) background to smuon-pair production. • See my “forward detector” talk at SLAC, Jan 04. • Potential implications for SUSY reach in dark matter favored “stau-coannihilation” region. • Plots are for an electron veto at 25 mrad • Absolute normalization arbitrary. Signal is blown up by a factor of ≈20,000 for visibility • Work in progress. Di-muon pT / Eb √s=800, m_smu=335,DM=5.8 (GeV) Graham W. Wilson

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