[en] New applications for single particle and photon detection in many fields require both large area imaging performance and precise time information on each detected particle. Moreover, a very high data acquisition rate is desirable for most applications and eventually the detection and imaging of more than one particle arriving within a microsecond is required. Commercial CCD systems lack the timing information whereas other electronic microchannel plate (MCP) read-out schemes usually suffer from a low acquisition rate and complicated and sometimes costly read-out electronics. We have designed and tested a complete imaging system consisting of an MCP position readout with helical wire delay-lines, single-unit amplifier box and PC-controlled time-to-digital converter (TDC) readout. The system is very flexible and can detect and analyse position and timing information at single particle rates beyond 1 MHz. Alternatively, multi-hit events can be collected and analysed at about 20 kHz rate. We discuss the advantages and applications of this technique and then focus on the detector's ability to detect and analyse multiple hits

[en] We have developed a novel delay-line anode design based on L/2 shifted maeander-lines for the readout of open-faced and sealed MCP-based detectors. In combination with the sealed detector (image intensifier) we are able to provide position and time sensitive single photon detection from near UV to near IR. (orig.)

No abstract available

[en] A low energy electron diffraction (LEED) instrument incorporating a delay line detector has been constructed to rapidly collect high-quality digital LEED images with low total electron exposures. The system uses a position-sensitive pulse-counting detector with high bias current microchannel plates. This delay-line detector combined with a femtoampere electron gun offers a wide range of flexibility, with electron dosing currents ranging from 0.15 pA to 0.3 fA. Using the highest current setting and collecting 1x10⁶ counts per image, individual LEED images can be completed in 4 s with an acquisition rate of 250 kHz and a total electron exposure of 5x10⁶ electrons. Under the latter conditions, images can be collected in 20 min with an acquisition rate of 1 kHz with a total electron exposure of 2x10⁶ electrons. An angular width of 0.13 deg. at 108 eV is demonstrated, which means that domain sizes as large as 600 A can be resolved, depending on the surface quality of the crystal. The system electronics collect 2048x2048 pixel images with a spatial resolution of about 75 μm. The dynamic range of this system is 32 bits/pixel (limited only by physical memory). The construction of the detector results in a 'plus'-shaped artifact, which requires that, for a given sample orientation, two images be taken at a relative angle of 45 deg. Identical current-voltage curves from an MgO(111)1x1 H terminated sample, taken during several hours of exposure to the low current electron beam, demonstrate minimal electron induced H desorption

[en] We have measured the ionization and fragmentation of Helium, Neon and Argon Dimers induced by ion impact and observed two different pathways, the sequential ionization on each atom and the interatomic Cou-lombic decay