We report on the construction of a UHV compatible 40 mm active diameter detector based on micro channel plates and assembled directly on the feed-throughs of a DN63CF flange. It is based on the charge division technique and uses a standard two inch Si wafer as a collector. The front end electronic is placed directly on the air side of the flange allowing excellent immunity to noise and a very good timing signal with reduced ringing. The important aberrations are corrected empirically providing and absolute positioning accuracy of 500 $mu$m while a 150 $mu$m resolution is measured in the center.
A position-sensitive, high-resolution time-of-flight detector for fission fragments has been developed. The SPectrometer for Ion DEterminiation in fission Research (SPIDER) is a $2E-2v$ spectrometer designed to measure the mass of light fission fragments to a single mass unit. The time pick-off detector pairs to be used in SPIDER have been tested with $alpha$-particles from $^{229}$Th and its decay chain and $alpha$-particles and spontaneous fission fragments from $^{252}$Cf. Each detector module is comprised of a thin electron conversion foil, electrostatic mirror, microchannel plates, and delay-line anodes. Particle trajectories on the order of 700 mm are determined accurately to within 0.7 mm. Flight times on the order of 70 ns were measured with 200 ps resolution FWHM. Computed particle velocities are accurate to within 0.06 mm/ns corresponding to precision of 0.5%. An ionization chamber capable of 400 keV energy resolution coupled with the velocity measurements described here will pave the way for modestly efficient measurements of light fission fragments with unit mass resolution.
TORCH is a time-of-flight detector that is being developed for the Upgrade II of the LHCb experiment, with the aim of providing charged particle identification over the momentum range 2-10 GeV/c. A small-scale TORCH demonstrator with customised readout electronics has been operated successfully in beam tests at the CERN PS. Preliminary results indicate that a single-photon resolution better than 100 ps can be achieved.
Principles of operation, construction and first test results of a Dielectric Resistive Plate Chamber (DRPC) are described. The detector has shown stability of operation in the avalanche mode of gas amplfication within a wide range of applied voltages. Double-gap DRPCs have demonstrated the MIP registration efficiency of 97% and the time resolution of 180-200 ps. No changes in DRPC operation have been observed with test beam intensities up to 10^3 Hz/cm^2.
We have developed image intensifier tubes with delay-anode read-out for time- and position-sensitive photon counting. The timing precision is better than 1 ns with 1000x1000 pixels position resolution and up to one megacounts/s processing rate. Large format detectors of 40 and 75 mm active diameter with internal helical-wire delay-line anodes have been produced and specified. A different type of 40 and 25 mm tubes with semi-conducting screen for image charge read-out allow for an economic and robust tube design and for placing the read-out anodes outside the sealed housing. Two types of external delay-line anodes, i.e. pick-up electrodes for the image charge, have been tested. We present tests of the detector and anode performance. Due to the low background this technique is well suited for applications with very low light intensity and especially if a precise time tagging for each photon is required. As an example we present the application of scintillator read-out in time-of-flight (TOF) neutron radiography. Further applications so far are Fluorescence Life-time Microscopy (FLIM) and Astronomy
To achieve high precision and accuracy for mass measurements of exotic nuclei by Time-of-flight (TOF) methods: high-resolution beam-line magnetic-rigidity time-of-flight (B$rho$-TOF) and in-ring isochronous mass spectrometry (IMS), a large-area electrostatic detector which possesses high position resolution and good timing resolution at the same time is developed at the Rare-RI Ring in RIBF, RIKEN Nishina Center, Japan. Besides TOF mass measurements, the detector system will also be used for heavy ion beam trajectory monitoring or momentum measurements for both beam-line and in-ring at the Rare-RI Ring. The position and timing measurements of heavy ions are performed by detecting the secondary electrons (SEs) emitted from a conversion foil during the passage of the ion. The SEs are accelerated and bent with an angle of $90^{circ}$ by electrostatic fields onto a micro-channel-plate (MCP) electron multiplier which is coupled with a position-sensitive delay-line anode. The dependence of the timing and position resolution on applied high voltages of the detector potential plates has been studied systematically via simulation and experimentally. An isochronous condition of secondary electron transmission in the electrostatic field of the detector is chosen to optimize the structure of the detector for high performance. The best achieved timing resolution is less than 50 ps (in $sigma$) and position resolution $sim$ 1 mm (in $sigma$) for 2 dimensions, respectively. The overall efficiency is $sim$ 95$%$ for heavy ion beam and $sim$ 75$%$ for $alpha$ particle from $^{241}$Am source.
S. Lupone
,S. Damoy
,A. Husseen
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(2015)
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"A large open ratio, time and position sensitive detector for time of flight measurements in UHV"
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Philippe Roncin
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