This paper describes the performances of a large volume drift chamber with complete digitization of the output pulses. The electronics used in this test include wide-band (700MHz) amplifiers and fast (1 Gsample/s) digitizers. The gas mixture selected for drift chamber operation (80% He–20% CH4) and the signal processing mentioned above allow the measurement of the primary ionization clusters. The improvement in the (wire) impact parameter evaluation of the primary particle is sizeable.

A full size prototype of the KLOE drift chamber has been constructed and exposed to a 50 GeV/c pion beam at CERN. Five hundred single sense wire square cells, 3 x pi cm(2) and 1.5 x pi/2 cm(2), arranged in thirty layers (approximately 2300 wires in total), have been strung at stereo angles ranging from 50 to 120 mrad between two cone shaped carbon fiber end plates. Results on the studies of the time-to-distance relations, on spatial and dE/dx resolutions in a 90%He - 10%iC(4)H(10) gas mixture are presented together with the main ideas underlying the algorithm used for reconstructing straight tracks in an all stereo drift chamber.

An automated stringing facility has been built for the KLOE Drift Chamber under construction at LNF. Due to the large number of wires, we need to reduce the possibility of errors and the time of each operation. The stringing facility uses three robots remotely controlled by two computers running LabVIEW. All the operations will be made in a clean room, class 1000 in the chamber area, 1000 elsewhere, with inside temperature of 20+/-1 degrees C and relative humidity of 50+/-1%.

A status report on the construction of the drift chamber for the KLOE experiment at the LNF DA Phi NE Phi-factory is given. Physics requirements, detector design performance and its key mechanical features and components are briefly reviewed. The program currently consists of (i) the preparation of final detector components, complemented by (ii) extensive tests of prototypes of critical mechanical parts (like the end plates) and the ''test construction'' of a 1:1 chamber prototype. These two sub-programs are pursued in parallel. Single-component prototype checks include surveys of their shape and size, of accuracy of wire-hole drilling, measurements of their displacement or buckling under nominal load. The ''test construction'' is the debugging of mechanical assembly, survey and alignment of mechanics and of wire-stringing robotics, the actual stringing of a sample 2000 holes drilled on the prototype end plates, the measurement of electrical properties of strung wires, as well as of their mechanical tension. These extensive tests have been successfully completed; they represent an effective hands-on training of the construction group, and will allow a prompt and steady start of the drift chamber wire stringing as all necessary components became available at LNF.

A fast second level trigger has been developed for the ARGUS experiment which recognizes tracks originating from the interaction region. The processor compares the hits in the ARGUS micro vertex drift chamber to 245 760 masks stored in random access memories. The masks which are fully defined in three dimensions are able to reject tracks originating in the wall of the narrow beampipe of 10.5 mm radius.

One of the main problems in the use of cluster counting for particle identification in high energy physics is the huge primary data rate. By means of an online data reduction system, this data rate can be reduced to the amount known from conventional integral charge/time readout. For tests and optimization of online data reduction algorithms, a RISC-based, data-flow-oriented multiprocessor board has been designed.