References

• Books
  • Semiconductor Detector Systems by Helmuth Spieler
    • much more educational book
  • Pixel Detectors: From Fundamentals to Applications by L Rossi, P Fischer, T Rohe and N Wormes, Springer.
    • Leo Rossi was ATLAS pixel collaboration leader before 2006. Whatever he put in this book is based on ATLAS pixel detector.
    • Tilman R. was one of the key people in sensor design.
    • Peter F. early chip design, Norbert W. solder bump bonding.
    • Maurice comments that "This book is not a particularly good introduction and it can not possibly mention any lessons we learned building the detector. It is too narrowly focused and the motivation of the authors was more to write a book as early as possible than to teach inexperienced people."
  • Detectors for Particle Radiation by Konrad Kleinknecht
    • derive the formula for the momentum resolution of track
  • Preshower thesis
    • CERN-THESIS-2001-023, Oct 2001.: The design and development of the front-end electronics for the CMS preshower detector. by P. Aspell (Lyon, IPN) . Thesis (Advisor: P. Bloch and B. Ille).
• Advise to give talks
  • pdf: John Conway's advise

Paper Reading

ATLAS pixel and CMS preshower

• Articles
  • NUPHZ,172,67: Overview and status of the ATLAS Pixel Detector. by Andreas Korn
  • CMS NOTE-2000/061 ECAL Silicon sensors for the CMS Preshower, by A. Peisert and N. Zamiatin. This note has been refined and published as below
    • NIMA 479 (2002) 265: Silicon sensors for the CMS preshower detector, by Ph. Blocha, et al.
• May 19 2008, 5pm Mon, Bdg 14 4-009, Shih-Chieh (Pixel) & Chin-Chi (Preshower)
  • What is the benefit of using p-bulk other than n-bulk?
    • p-bulk is more rad-hard but hard to fabricate. See Nucl.Phys.Proc.Suppl.172:17-19,2007: Ultra radiation hard silicon detectors for future experiments: 3D and p-type technologies by G. Pellegrini et al.
  • Explain what is p-spray and p-stop.
    • different processes of etching-masking-doping to make inter-pixel isolation
    • p-stop is like making strip in between n strip; p-spray is filling p type implant into all the space in between n strip.
    • p type is usually Boron (B); n type is usually Arsenic (AS).
    • Rong-Shyang remembered that n+/p+ means heavily doped compare to the lightly doped bulk silicon -> Need to be double checked.
    • p-spray has lower p type dopper concentration between n type electrodes and the lateral electric field decrease after irradation. More details see Sec 2.5.3.1 in Pixel Detectors by RFRW.
    • More references see:
      • NIMA465,83: Fabrication of ATLAS pixel detector prototypes at IRST. by M. Boscardin, G.F. Dalla Betta, P. Gregori, M. Zen, N. Zorzi (ITC-IRST, Trento) . 2000.
      • RD50: ATLAS pixel sensor at IRST
      • Pix2000: Fabrication of ATLAS pixel detector
      • seminar at FNAL: page 3 and page 4 have illustrations for p-stop and p-spray used to isolate n+ strip/pixel.
  • Estimate the average collisions per bunch crossing at LHC and Belle.
    • LHC collision rate: 25 ns bunch spacing, 31.6M Hz bunch crossing rate and 600MHz event rate for in-elastic collisions
  • Estimate the momentum resolution of trackers at ATLAS and CMS.
    • Yeng-Ming's solution
  • Estimate the resolution of Z position of single track along beam pipe of ATLAS and CMS by using silicon tracker only.
  • Estimate the position resolution of CMS preshower.
    • Since particle will go through a 2X0 and 1X0 material. The silicon sensor will hit by a bunch of particles rather than a single track. We use the energy weighted method (center of gravity) to obtained the X and Y position. If we have more material in front of silicon sensor, we can have better resolution. This method will further corrected by the empirical S-curve.
  • Estimate the maximum pi0 pT that can be discriminated from single photon by CMS preshower and compare it to CDF.
    • given the spatial resolution of preshower, one can estimate the maximum pT of pi0 can be resolved from single photon.
    • http://cmsdoc.cern.ch/documents/99/note99_076.pdf - this note studies the performance of applying NN on pi0 rejection at Level2 trigger.
    • Another way to ask similar question is described in NIMA 461 (2001) 355
      • For a Higgs mass of 120 GeV, the π0's have a transverse energy of the order of 60 GeV leading to a separation between the 2 photons arising from the π0 decay of about 0.8 cm in the barrel region while it is only few millimetres in the endcaps. (still need people show the math)
      • The Image electromagnetic calorimeter is made of PbWO4 crystals with a front face of about 2.2×2.2 cm2 in the barrel and 2.9×2.9 cm2 in the endcap. The π0 rejection can be performed with the crystal calorimeter in the barrel, whereas in the endcap the crystals cannot resolve the 2 photons from π0 decays: a fine-grain photon-sensitive detector (preshower) is needed in this region. -> this gives a strong motivation to describe why preshower at CMS is attractive
  • Estimate the energy resolution of froward EM showers at CMS with and without preshower or with preshower but worse calibration.
    • http://cmsdoc.cern.ch/documents/00/note00_001.pdf
  • Explain what is the NIEL and equivalent neutron radiation nose.
    • NIEL is nonionizing energy loss, which causes the major radiation damage effect on bulk silicon. NIEL depends on incident particle type and kinetic energy.
    • Reference and conversion table : G. P. Summers, E. A. Burke, P. Shapiro, S. R. Messenger, and R. J. Walters, “Damage correlations in semiconductors exposed to gamma, electron and proton irradiations,” IEEE Trans. Nucl. Sci., vol. 40, pp. 1372-1379, Dec. 1993. pdf
  • Explain what is type inversion and compare this property of ATLAS and CMS tracker.
    • type inversion is change of effective doping in bulk silicon, e.g. p+/n/n+ to p+/p/n+ structure. It can be described by the combined effects of phosphor dopant de-activation and acceptor state creation.
    • Reference of an early experiment : Pitzl, D. and 10 others. Type Inversion in Silicon Detectors. Nucl. Instrum Methods A311, 98–104 (1992). pdf: Delta: a charge sensitive front-end amplifier with switched gain for low-noise, large dynamic range silicon detector readout,
• Jun 2 2008, 5:30pm Mon, Bdg 14 4-002, Yeng-Ming (Preshower)
  • What is leakage current compensation mechanism? What is the typical size of leakage current at preshower and what is the relationship between leakage current and the irradiation doze?
  • How leakage current is measured and monitored at preshower? (Syue-Wei)
  • 3 mins introduction to p-n junction. (Yeng-Ming)
    • the p-n junction in allaboutcircuits.com
• June 9 2008, 5:00 pm Mon, Bdg 14 4-002, Shih-Chieh
  • Useful reference
    • Investigation of Silicon Sensors Quality as a Function of the Ohmic Side Processing Technology, Ph. Bloch, .etc.,
      • study the breakdown voltage dependence on the depth of the effective "n+" layer
    • Nucl. Instr. and Meth. A 461 (2001), Delta: a charge sensitive front-end amplifier with switched gain for low-noise, large dynamic range silicon detector readout by P. Aspell
      • The equivalent noise charge, r.m.s., of the preamplifier is expected to be ENCpreamplifier=640+33×C(electrons) where C, in pF, is the total strip capacitance. The total strip capacitance of a Preshower sensor is about 50 pF, depending on the wafer thickness. The amplifier noise, including the load capacitance, is therefore expected to be around 2300 electrons.
  • Estimation of preshower capacitance
    • Shih-Chieh's rough estimation
  • Derive formula in p 269 in NIMA 479 (2002) 265. The relationship between backplane capacitance C_b, interstrip capacitance C_i and total strip capacitance C_tot
  • pp4. What is analog memory? What is DC level?
  • pp4. Is preshower using DC or AC amplifier?
  • pp4. Why a high shaper gain, 32mV/4fC, corresponds to about 780 electrons?
  • pp4. Why a low shaper gain, 4mV/4fC, corresponds to about 6250 electrons?
  • pp4. How many average number of MIPs per strip expect at 10^34 cm-2s-1?
  • pp4. Please summarize the equivalent electron nose of leakage current, amplifier and shaper for preshower. What is the designed consideration and what is the real performance?
• June 16 2008
  • sec 4.1-4.3 (Kai-Feng)
  • sec 4.4-4.6 (Yen-Ming)
  • sec 5-7 (Shih-Chieh)

ATLAS Pixel detector

Pixel Barrel

Pixel Endcape

-- ShihChiehHsu - 13 May 2008