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The nuclear microbeam analysis techniques of proton-induced X-ray emission (PIXE) and nuclear reaction analysis (NRA) have been used to probe the distribution of carbon and other elements in used fluid catalytic cracking catalyst particles. The catalyst was sampled from the stripper standpipe in one of Shell's commercial riser FCC units processing feedstocks containing up to 4 wt% Conradson carbon residue (CCR). PIXE and NRA gave quantitative information on the metal and carbon distributions. Samples were embedded in waterglass (Na 2 O·SiO 2 ) to overcome the problem of carbon contamination from conventional embedding materials. Elemental line scans and images were obtained with a spatial resolution of a few microns and sufficient sensitivity to allow quantification of all elements of interest. Correlations were found between the spatial distribution of Ti, V, and, to a lesser extent, Fe. Ni was found to be confined to the outermost 10 μm or so of each particle. The degree of correlation appeared to reduce with particle age. Despite the high CCR content of the feedstock, it was found that carbon was uniformly distributed through the particles, indicating that even the bulkier molecules present in the feed are cracked on the external surface of the FCC particle.

A description is given of the software algorithms used for the Optical Fiducial Volume Trigger system (OFVT) and the implementation on-line. The OFVT system has the purpose of enhancing the efficiency of the trigger system for the Rapid Cycling Bubble Chamber (RCBC) of the European Hybrid Spectrometer (EHS). One obtains an efficiency for good events of 80–90% and a rejection efficiency for events outside the bubble chamber fiducial volume of 60–70%. With the use of OFVT the fraction of pictures containing a useful event rises from 30% to 55%.

The European Hybrid Spectrometer is described in its preliminary version for the NA16 charm experiment. The performance of the small hydrogen bubble chamber LEBC and the detectors of the spectrometer is discussed. In particular the combination of the bubble chamber information with the spectrometer data is described in detail. The track reconstruction efficiency is 90%. The precision with which vertices seen in the bubble chamber are reconstructed is around 10 μm and the two track resolution is 40 μm. Therefore very complex event configurations, in particular charm particle decays, can be reconstructed correctly.

ESOP is a fast processor designed to front-end the data-acquisition computer in high energy physics experiments and perform second level trigger calculations. It is in use in five experiments at CERN and Saclay. It will be shown how ESOP realises its high performance and how such a machine may be supported in an experiment. For trigger calculations the efficiency of the connection to the detector read-out system is extremely important and the ways in which this is done in practice with ESOP will be discussed. An outline of some existing trigger algorithms will be given and some conclusions drawn on desirable features of a second-generation processor based on experience with ESOP.

A scanning system and control hardware are described which measures the ionisation density of bubble chamber tracks. The device is attached to a conventional film plane digitising measuring machine.

A bubble chamber experiment is described in which observations were made of the elastic and inelastic interactions of positive kaons with protons. Total elastic and inelastic cross sections, partial inelastic cross sections and elastic-scattering angular distributions are given at 9 kaon momenta in the range 0.9 to 1.5 GeV/ c . A phase shift analysis of the elastic channel is presented using these data in combination with previous data and recent polarisation data.

A description is given of multiprocessor on-line systems, based on NORD computers, for large physics experiments at CERN. In complex experiments the data acquisition and control functions may be performed by different CPUs in a dual 16-bit NORD-100 computer system. Some configurations include a 32-bit NORD-50 processor, allowing large analysis programs to be implemented and executed in the on-line system. Several examples from currently running CERN physics experiments are given.