N. A. Korotkova

New method for determining energies of cosmic-ray nuclei

A new procedure for determining the energies of particles of primary cosmic radiation is described. The procedure is based on measuring the spatial density of the flux of secondary particles originating from the first event of nuclear interaction that have traversed a thin-converter layer. The use of the proposed method makes it possible to create equipment of comparatively small mass and high sensitivity. The procedure can be applied in balloon-and satellite-borne cosmic-ray experiments with cosmic nuclei for all types of nuclei over a wide energy range between 1011 and 1016 eV per particle. Physical foundations of the method, results of a simulation, and the applicability range are described.

The ATLAS transition radiation tracker

The transition radiation tracker of the ATLAS setup, which is one of the two multipurpose detectors at the Large Hadron Collider (LHC), its design, and the tasks it performs are described. The tracker is fully assembled and commissioned. The first physical results obtained by the tracker in the ATLAS cosmic muon runs are presented.

Testing the prototype of the NUCLEON setup on the pion beam of the SPS accelerator (CERN)

A technique for determining the energy of primary cosmic rays in the range of 1012–1015 eV has been developed. The idea behind this technique consists in measuring the spatial flux density of secondary particles produced in the first act of inelastic nuclear interaction inside a target and passed through a thin converter layer in which the electromagnetic component (photons from decays of neutral pions) is multiplied. This technique has been developed by generalizing the well-known Castagnoli method (for measuring the angular characteristics of tracks of secondary particles produced in the first act of inelastic nuclear interaction inside a target), and its application offers a chance to design instruments for scientific studies such that their mass is relatively low while their luminosity is high. It is proposed to use this technique in a satellite-based NUCLEON experiment. The technique has been tested on charged particle beams of the SPS accelerator at CERN. Results of these tests confirm that, using this method, it is possible to measure the particle energy and, therefore, perform an orbital scientific experiment with the proposed equipment.

The NUCLEON experiment: The current status

The main purpose of the NUCLEON experiment is direct measurements of the energy spectra of cosmic rays in the range 1011–1015 eV with the use of the lightweight facility during a prolonged orbital flight. The energy is determined using a technique based on the measurement of the spatial density of secondary particles produced in the initial event of inelastic interaction. The schematic diagram of the NUCLEON facility, the current status of the project, the results of testing the prototype, and plans are presented.

An Instrument to Measure Elemental Energy Spectra of Cosmic Ray Nuclei up to 1016 eV

Abstract A longstanding goal of cosmic-ray research is to measure the elemental energy spectra of cosmic rays up to and through the “knee” (≈3×10 15 eV). It is not currently feasible to achieve this goal with an ionisation calorimeter because the mass required to be deployed in Earth orbit is very large (at least 50 tonnes). An alternative method is presented. This is based on measuring the primary particle energy by determining the angular distribution of secondaries produced in a target layer using silicon microstrip detector technology. The proposed technique can be used over a wide range of energies (10 11 –10 16 eV) and gives an energy resolution of 60% or better. Based on this technique, a design for a new lightweight instrument with a large aperture (KLEM) is described.

The use of capacitive charge division in silicon microstrip detectors

The structure of silicon microstrip detectors with a great number of passive strips located between the readout (active) strips is described. Owing to the use of capacitive charge division among the passive and active strips, it is possible to essentially increase the readout pitch and to reduce the number of electronic readout channels by five to ten times. Since the cost of the front-end electronics exceeds significantly that of the detectors themselves, this method allows the cost of the entire detector-electronics system to be decreased severalfold without substantial deterioration of the position resolution.