Nuclear Instruments and Methods in Physics Research最新文献

Some results on the precision obtainable using automatic devices in nuclear emulsion measurements and simplified methods for their application in standard work are presented.

The design of the central calorimeter of the UA2 experiment at the CERN $\text{p}$p collider is described. Calibration methods and test beam results are presented.

Recent attempts to operate counters for calorimetric use inside high intensity magnetic fields have resulted in interesting developments both in the construction of the counters and in the design of the vacuum photosensitive devices. In particular, a new one-stage photomultiplier has been developed. The present status of the development of gas photodiodes will finally be illustrated.

The status of liquid argon calorimeters is reviewed and experiences obtained with these devices are given. Future perspectives of the liquid ionization chamber technique in calorimetry are also discussed.

Following the thallium formate solution and the thallium formate-malonate (Clerici) solution, we have tested several lead compound solutions and a tetrabromoethane heavy liquid as a Cherenkov radiator material for a total absorption counter (calorimeter). We report here the results of optical transmission measurements of a binary solution of lead acetate and lead propionate and of a tetrabromoethane heavy liquid. We present also a result of trials of mixing organic scintillators in these heavy liquids to increase the light output. At present, we have neither obtained an adequate scintillator for lead compound solutions, nor for a tetrabromoethane heavy liquid. However, we obtained a promising indication of getting scintillations from a mixture of thallium formate-malonate (Clerici) solution, water and a liquid scintillator added with a surfactant and a naphthalene in a colloidal state. We need to examine the data more carefully and quantitatively before making a definite affirmative conclusion.

A fine sampling, tracking hadron calorimeter operating with limited streamer tubes and using a copper absorber has been tested with pions from 1 to 10 GeV/c. The energy resolution measured is consistent with the one expected from empirical formulae obtained for scintillator calorimeters, thus demonstrating that streamer tubes bring little or no loss in resolution. Our laboratory tests have demonstrated that chambers using tubes as small as 3.5 × 4.5 mm² can operate satisfactorily in limited streamer mode.

The purpose of this paper is to describe a novel charge transport scheme in semiconductors, in which the field responsible for the charge transport is independent of the depletion field. The application of the novel charge transport scheme leads to the following new semiconductor detectors:

• 1.

  1) Semiconductor drift chamber;

• 2.

  2) Ultralow capacitance - large area semiconductor X-ray spectrometers and photodiodes;

• 3.

  3) Fully depleted thick CCD.

Special attention is paid to the concept of the semiconductor drift chamber as a position sensing detecter for high energy charged particles. Position resolution limiting factors are considered and the values of the resolutions are given.

The high density projection chamber (HPC) is a large volume gas sampling calorimeter. The highly granulated module allows a complete three-dimensional reconstruction of the shower and offers good energy resolution. We will present preliminary results from test runs and discuss operation in a magnetic field.

A large TPC is described which is being designed for a LEP experiment. The main components are discussed with some emphasis on the wire chamber design and on the obtainable measurement accuracy. Some test results are reported.

We outline briefly the general structure of the Aleph detector, to place in context conceptually and physically the electromagnetic calorimeter. The calorimeter is then described, emphasizing the read-out mechanical and electronic structure, which allows adequate granularity; three layers of towers 3×3 cm², approximately 210 000 pieces of analog information. We discuss the basic properties of such apparatus with the results of tests performed on a prototype. We emphasize the peculiarities of operating such a wire gas calorimeter in a strong magnetic field parallel to the wires.