The CDF II Level 1 Track Trigger Upgrade Jones, M.; Abulencia, A.; Azzurri, P. ...
IEEE transactions on nuclear science,
02/2008, Letnik:
55, Številka:
1
Journal Article
Recenzirano
The CDF II detector uses dedicated hardware to identify charged tracks that are used in an important class of level 1 trigger decisions. Until now, this hardware identified track segments based on ...patterns of hits on only the axial sense wires in the tracking chamber and determined the transverse momentum of track candidates from patterns of track segments. This identification is efficient but produces trigger rates that grow rapidly with increasing instantaneous luminosity. High trigger rates are a consequence of the large numbers of low momentum tracks produced in inelastic collisions which generate overlapping patterns of hits that match those expected for high-momentum tracks. A recently completed upgrade to the level 1 track trigger system makes use of information from stereo wires in the tracking chamber to reduce the rate of false triggers while maintaining high efficiency for real high momentum particles. We describe the new electronics used to instrument the additional sense wires, identify track segments and correlate these with the track candidates found by the original track trigger system. The performance of this system is characterized in terms of the efficiency for identifying charged particles and the improved rejection of axial track candidates that do not correspond to real particles.
Objective The aim of this study was to evaluate the long-term fate of the cryopreserved mitral homograft focusing on structural valve deterioration. Methods Homograft replacement of the mitral valve ...was performed in 106 patients. The causes of mitral disease were rheumatic disease (n = 75), endocarditis (n = 24), and others (n = 7). There were 40 partial homografts and 66 total homografts. Results Mean follow-up was 9.3 + 4.7 years (up to 17.8 years). There were 5 early (<3 months) and 15 late deaths. There have been 5 early (<3 months) and 30 late reoperations. Five patients had endocarditis, and 5 patients had an ischemic/hemorrhagic event. Compared with baseline, follow-up echography showed progression of mitral regurgitation grade (from 0.4 to 1.3; P < .001) with stenosis (elevated gradient: from 3.9 to 7.0 mm Hg; P < .001) and decreased valve area (from 2.3 to 1.7 cm2 , P < .001). Freedom from structural valve deterioration was 90%, 76%, and 65% at 5, 10, and 15 years, respectively. Structural valve deterioration was more frequent in total homografts ( P = .018 vs partial homografts) and in case of pregnancy ( P = .016 vs no pregnancy). Stenosis related to structural valve deterioration was more pronounced for age less than 40 years ( P = .03) and ring size 30 mm or less ( P = .002). Pathologic analysis of the explanted homografts almost invariably showed dense fibrosis with calcification and no cellularity. Conclusions Mitral homografting was accomplished with early echographic results similar to those of valve repair. Structural valve deterioration produced mixed stenosis with insufficiency, and its incidence was comparable to that of bioprostheses structural valve deterioration. An improvement in the preservation mode of valvular homografts is warranted.
eXtremely Fast Tracker trigger upgrade at CDF Abulencia, A.; Azzurri, P.; Cochran, E. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2009, 2009-1-00, 2009-01-01, Letnik:
598, Številka:
1
Journal Article
Recenzirano
The CDF II eXtremely Fast Tracker (XFT) is a trigger processor which reconstructs charged particle tracks in the transverse plane of the central tracking chamber. The XFT tracks are also extrapolated ...to the electromagnetic calorimeter and muon chambers to generate trigger electron and muon candidates. The XFT is crucial for the entire CDF II physics program: it detects high
P
t
lepton from
W
/
Z
and heavy flavors decay and, in conjunction with the level 2 processor, it identifies secondary vertices from beauty decay. The XFT has thus been crucial for the recent measurement of the
B
s
0
oscillation and
Σ
b
. The increase of the Tevatron instantaneous luminosity demanded an upgrade of the system to cope with the higher occupancy of the chamber. In the upgraded XFT, three-dimensional tracking reduces the level of fake tracks and measures the longitudinal track parameters, which strongly reinforce the trigger selection. This allows to maintain the trigger perfectly efficient at the record luminosities
2
–
3
×
10
32
cm
-
2
s
-
1
and to maintain intact the CDF II high luminosity physics program, which includes the Higgs search. In this paper we review the architecture, the used technology, the performance and the impact of the upgraded XFT on the entire CDF II trigger strategy.
The CDF II eXtremely Fast Tracker Upgrade Abulencia, A.; Errede, D.; Gerberich, H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2007, Letnik:
581, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The CDF II eXtremely Fast Tracker (XFT) is the trigger processor which reconstructs charged particle tracks in the CDF II central outer tracking chamber. The XFT tracks are also extrapolated to the ...electromagnetic calorimeter and muon chambers and are associated to electromagnetic clusters and muon stubs to generate trigger electron and muon candidates. The steady increase of the Tevatron instantaneous luminosity and the resulting higher occupancy of the chamber demanded an upgrade of the original system, which performed tracking only in the transverse plane of the chamber and was consequently affected by a significant level of fake tracks. In the upgraded XFT, tracking is reinforced by using additional data from the stereo layers of the chamber to reduce the level of fake tracks and to perform three-dimensional track reconstruction. A review of this upgrade is presented.
The CDF II eXtremely Fast Tracker upgrade Abulencia, A.; Azzurri, P.; Cochran, E. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2007, Letnik:
572, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The CDF II eXtremely Fast Tracker is the trigger track processor which reconstructs charged particle tracks in the transverse plane of the CDF II central outer tracking chamber. The system is now ...being upgraded to perform a three dimensional track reconstruction. A review of the upgrade is presented here.
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