Transmissive x-ray beam position monitors with submicron position- and submillisecond time resolution.

We present the development of fast transmissive center-of-mass x-ray beam position monitors with a large active area, based on a thinned position sensitive detector in both a duo- and a tetra-lateral variant. The detectors were tested at BESSY beamlines BL14.1, KMC-1, and KMC-2 and yielded signal currents of up to 3 microA/100 mA ring current at 10 keV photon energy using the monochromatic focused beam of BL14.1. The active area sizes were 1 x 1 and 3 x 3 mm(2) for the duo-lateral and 5 x 5 mm(2) for the tetra-lateral devices, with the duo-lateral detectors currently being available in sizes from 1 x 1 to 10 x 10 mm(2) and thicknesses between 5 and 10 microm. The presented detectors' thicknesses were measured to be 5 and 8 microm with a corresponding transmission of up to 93% at 10 keV and 15% at 2.5 keV. Up to a detection bandwidth of 10 kHz, the monitors provide submicron position resolution. For lower detection bandwidths, the signal-to-noise reaches values of up to 6 x 10(4) at 10 Hz, corresponding to a position resolution of better than 50 nm for both detector sizes. As it stands, this monitor design approach promises to be a generic solution for automation of state-of-the-art crystal monochromator beamlines.

Visual attention in orienteers at different levels of experience.

This study explored how differences in orienteering experience are related to differences in how visual attention is allocated to the map, the environment and to travel. Twenty more experienced and 20 less experienced individuals orienteered while wearing a head-mounted video camera with microphone. The participants verbalized what they were attending to (map, environment or travel) at any given time. Each recorded film was coded at each point in time in terms of what the participant was attending to and whether the participant was moving or stationary. More experienced orienteers attended to the map markedly more while moving and spent less time stationary than less experienced orienteers. The participants' performance was significantly related to the ability to attend to the map while moving. The strategic control of attention is proposed to explain this ability. It is proposed that attentional training might enhance performance in sports characterized by multiple and dynamically varying elements.

The use of heuristics during route planning by expert and novice orienteers.

Expert orienteers have reported using two heuristics when planning routes to points in the environment that must be located, known as 'controls'. These heuristics constitute attending to the start first and subsequently planning forward to a given control, and attending to the control first and planning backwards to the start. The aim of this study was to establish which heuristic experts use predominantly and whether novices' use of these heuristics differs from that of experts. Two methods for tracing attention were used while 20 expert and 20 novice orienteers planned routes in the laboratory. The results were used to infer the use of heuristics. The orienteers were also interviewed about planning. We found that, when planning, experts generally attend to the control first and novices to the start first. There was also some evidence that novices work forwards from the start to the control and that experts work backwards from the control to the start. From the interviews, it would appear that experts regard the location of the control as the crux of the problem and prioritize this area during planning. These results have implications for an understanding of expertise and problem-solving in sport.