K. L. Byrum

Development of Picosecond-Resolution Large-Area Time-of-Flight Systems

The measurement of time-of-flight (TOF) of relativistic particles in high-energy colliders with picosecond resolution would qualitatively change the ability to identify underlying parton-level processes at future colliders or upgrades of existing detectors. We have measured the timing properties of three micro-channel plate photo-multiplier tubes (MCPPMTs) from Photonis; one with 1024 anodes and the other two with 64 anodes. The 1024-anode 10-micron pore tube uses a charge-collection scheme at the anode to provide equal arrival time of the signal independent of the hit position of incident light on the face of the tube. The two 64-anode 25-micron pore tubes have a commercially available collection scheme and were used to find a limit on the timing resolution. We have performed these measurements using a newly assembled test-stand based on a Hamamatsu PLP-10 picosecond laser and a commercial CAMAC readout electronics system. We present these results and compare timing properties to earlier versions of the charge collection scheme.

Position Measurements with Micro-Channel Plates and Transmission lines using Pico-second Timing and Waveform Analysis

The anodes of Micro-Channel Plate devices are coupled to fast transmission lines in order to reduce the number of electronics readout channels, and can provide two-dimension position measurements using two-ends delay timing. Tests with a laser and digital waveform analysis show that resolutions of a few hundreds of microns along the transmission line can be reached taking advantage of a few pico-second timing estimation. This technique is planned to be used in Micro-channel Plate devices integrating the transmission lines as anodes.

ULTRA-FAST TIMING AND THE APPLICATION OF HIGH ENERGY PHYSICS TECHNOLOGIES TO BIOMEDICAL IMAGING

We propose to apply the ultra fast Time Of Flight technique (TOR developed for High Energy Physics (HEP) particle detectors to biomedical imaging. The similarity of the problem in the two fields as well as the remarkable opportunities in biomedical imaging to use technologies developed in HEP have the potential to make major advances in the medical world, in particular for Positron Emission Tomography (PET). We will describe and present some preliminary results of the development of a new complete read-out chain able to manage signals from various types of modem photo detectors (MCP, APD, SiPM). This innovative architecture is made of a fast front-end electronics ASIC with novel Digital Signal Processing (DSP) concepts able to reach the Pico-second timing resolution, a time-to-digital converter, a pipelined digital readout and an integrated

Observation of the B{sub_c} Meson in p{ovr p} collisions at {radical}{ovr s} = 1.8 TeV.

We have observed bottom-charm mesons B_c via the decay mode Bc ->J/psi lepton neutrino in 1.8 TeV p-bar p collisions using the CDF detector at the Fermilab Tevatron. A fit of background and signal contributions to the J/psi + lepton mass distribution yielded 20.4 +6.2 -5.5 events from B_c mesons. A fit to the same distribution with background alone was rejected at the level of 4.8 standard deviations. We measured the B_c mass to be 6.40 +- 0.39 +- 0.13 GeVc^2 and the B_c lifetime to be tau(B_c) = 0.46 +0.18 -0.16 +- 0.03 ps. We measured the production cross section times branching ratio for B_c ->J/psi lepton neutrino relative to that for B+ ->J/psi K to be 0.132 +0.041 -0.037 (stat) +- 0.031 (syst) +0.032 -0.020 (lifetime).

Search for long-lived parents of Z{sup 0} bosons in p{ovr p} collisions at {radical}{ovr s} = 1.8 TeV.

We search for new long-lived particles which decay to Z{sup 0} bosons by looking for Z{sup 0}{yields}e{sup +}e{sup -} decays with displaced vertices. We find no evidence for parent particles of the Z{sup 0} with long lifetimes in 90 pb{sup -1} of data from the CDF experiment at Fermilab. We set a cross section limit as a function of the lifetime of the parent particle for both a generic Z{sup 0} parent and a fourth-generation, charge -1/3 quark that decays into Z{sup 0}b.