XFT L2 Upgrade

Participants:
    Charles Cox
    David Cox
    Robin Erbacher
    Rob Forrest
    Andrew Ivanov
    Alison Lister
    Aron Soha




Introduction:
 The XFT L2 Stereo Upgrade will include stereo information in the level 2 trigger system. The L1 path is used to confirm that the existing track (reconstructed with the axial COT layers only) goes through the stereo layers at the expected locations. At L2 the finer segmentation makes it possible to measure the angle of the track with respect to the beam axis as well as the distance from the centre of the detector along the beam axis and use that information to point the track to other detectors like the muon chambers, to see if the track is matched with the muon stub. To obtain the XFT stereo information at L2 the Stereo Finder boards are used. There are 36 finder boards, 12 for each superlayer, split into two different crates (b0xft06 and b0xft07). Each board contains 2 chips (chip A and chip B) which each look at only some of the fibers. The COT hits are combined into track segments and the phi position and slope are measured. The higher resolution data is sparsified then sent both to the T2FD bank and to one of the three pulsar boards vai the transition boards on the backplanes of the finder crates. The pulsar boards merge and concatenate the stereo pixel information. The pulsar sends the data over optical fibers into the L2 PC, the L2 PC runs the track reconstruction alogirithim and the L2 trigger algorithms.
   The 3D-tracks produced by the algorithims in the level 2 processors are extrapolated to the electromagnetic calorimeter towers and muon chambers to generate trigger electron and muon candidates. The invariant mass of track pairs and track isolations are also calculated and used in the level 2 trigger decision.

Results:
Online Operations
Data Volume
Trigger/Algorithim Performance
  
CDF Notes:
   CDF note 8975 - XFT L2 Upgrade note (draft)
   CDF note 7789 - XFT Stereo Mask Finding Specifications
   CDF note 4152 - describes data formats
   CDF note 7772 - revision of the data format for sending from the level 1 XFT Stereo Finder board to the level 2 Pulsar board
 

Other Links:
Scott's XFT page
Nils's XFT homepage
XFT e-log
XFT L2 Davis e-log
IEEE RT07 conference proceedings - describing the level 2 part of the XFT upgrade



Work in Progress