Yves Perrin

Further results in nuclear scattering radiography

A further investigation of the nuclear scattering of 500-1000 MeV protons is described. Three-demensional information on the desity distribution within carbon, CH and H2O phantoms is obtained with a volume resolution of 2 mm3. The separation of scattering on hydrogen from that on heavier nuclei, such as carbon and oxygen, is demonstrated, providing the statistics are sufficient. Some preliminary measurements on animals are reported, but with a volume resolution limited by statistics to 43 mm3.

Nuclear scattering radiography

The quasi-elastic scattering of 1 GeV protons permits the three-dimensional reconstruction of the density distribution in extended bodies. Fast multiwire proportional chambers are used to localize the position of every incoming and outgoing charged particle and to determine the coordinates at the interaction vertex. This article describes tests on a human head fixed in formalin. The comparison with computed tomography scans and anatomical sections is encouraging. Slices with a volume element of 5.5 mm3 illustrate the sensitivity of the method. The results also demonstrate the ability of the method to select the density distribution of hydrogen by making use of the kinematic relations specific to elastic scattering. Trials of this method in living humans are being planned.

Some Further Results in Nuclear Scattering Radiography

The work has shown that nuclear scattering radiography (NSR), is capable of a three-dimensional measurement of density distributions with a volume resolution of about 2 mm

Rejuvenation of a data acquisition system for fixed target experiments in a large multiuser spectrometer at CERN

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The use and possible abuse of transputer links

in objects of a size similar to that of a human head. Hydrogen radiographies are possible in addition to radiographies sensitive to density or atomic distribution. It is planned to make experiments under conditions of beam intensity and data rates compatible with full use of the potential advantages of the method for radiographies of living bodies.

The VALET-Plus, a VMEbus Based Microcomputer for Physics Applications

The new multiuser data acquisition system in operation at the CERN Omega spectrometer since July 1989 is described. Data are buffered from CAMAC, Fastbus, or VME front-ends during the beam spill while processing and event building take place off-spill under the control of standard processors in VME. The host is a VAX 6310, and data are stored on 3480-compatible cartridges. Standard software packages are used throughout, and the maximum throughput is about 1 MB/s (13 MB of data per spill). >

Proton Nuclear Scattering Radiography

Abstract The use of transputer links in data acquisition systems for high energy physics experiments is discussed. Link driving problems over distances of up to 30 m have been investigated. We report transper and error rates as well as procedures for error detection and recovery. The connection of transputers to data acquisition equiptment is considered and a practical example of an event builder application is given.

Progress in Nuclear Scattering Radiography

The VALET-Plus is a modular VMEbus based microcomputer system developed at CERN for use in applications such as the development and testing of electronics, equipment control and data acquisition. First released in 1985, more than 100 VALET-Plus systems are used today in 14 countries. The system will be described with particular emphasis on the SPIDER data acquisition package which offers both real time programming, using an interactive language, and fast data collection at rates of more than 1000 formatted events per second.

The integration of VAX and VALET-plus data acquisition software

Nuclear scattering of protons allows one to radiograph objects with specific properties: direct 3-dimensional radiography, different information as compared to X-ray technique, hydrogen radiography. Furthermore, it is a well adapted method to gating techniques allowing the radiography of fast periodic moving systems. Results obtained on different objects (light and heavy materials) are shown and discussed. The dose delivery is compatible with clinical use, but at the moment, the irradiation time is too long between 1 and 4 hours. Perspectives to make the radiography faster and to get a practical method are discussed.

Data-flow analysis for constraint logic-based languages

using conventional techniques of high energy physics, density distributions inside thick bodies can be mapped reconstructing the interaction vertex of charged particles in the GeV region. As compared to X-ray computer assisted tomography, nuclear scattering radiography offers the advantages of being fully three-dimensional and of reducing the overall radiation dose for a comparable image quality; furthermore, a subset of the data that corresponds to elastic interactions allows to measure the hydrogen density distribution in the object which is a unique feature of this method. Preliminary results obtained on a preserved human head are here presented.