arXiv subjects

C. P. Achenbach

Publications and source records attributed to C. P. Achenbach.

4 recordsLinked to original sources

arXiv2006

Computational studies of light acceptance and propagation in straight and curved multimodal active fibres

A Monte Carlo simulation has been performed to track light rays in cylindrical multimode fibres by ray optics. The trapping efficiencies for skew and meridional rays in active fibres and distributions of characteristic quantities for all trapped light rays have been calculated. The simulation provides new results for curved fibres, where the analytical expressions are too complex to be solved. The light losses due to sharp bending of fibres are presented as a function of the ratio of curvature to fibre radius and bending angle. It is shown that a radius of curvature to fibre radius ratio of greater than 65 results in a light loss of less than 10% with the loss occurring in a transition region at bending angles of pi/8 rad.

nucl-ex↗

arXiv2004

Active optical fibres in modern particle physics experiments

In modern particle physics experiments wavelength-shifting and scintillating fibres based on plastic polymers are used for tracking and calorimetry. In this review the role of photon trapping efficiencies, transmission functions and signal response times for common multimode active fibres is discussed. Numerical simulations involving three dimensional tracking of skew rays through curved fibres demonstrate the characteristics of trapped light. Of practical interest are the parametrisations of transmission functions and the minimum permissible radius of curvature. These are of great importance in today's experiments where high count rates and small numbers of photoelectrons are encountered. Special emphasis has been placed on the timing resolution of fibre detectors and its limitation due to variations in the path length of generated photons.

nucl-ex↗

arXiv2004

Development of a compact scintillator hodoscope with wavelength-shifting fibre read-out

We report on the prototyping of a plastic scintillator hodoscope with wavelength-shifting fibre read-out by a multi-anode photomultiplier as part of the development of a detector for cosmic ray muons to be carried aboard an aircraft. Light yield and light attenuation measurements on single- and double-clad wavelength-shifting fibres were performed. Low power, low-threshold, discriminators were designed. A prototype 16-channel hodoscope with two planes was built and tested with cosmic rays. After correcting for geometrical factors a global intrinsic efficiency of $ε> 98$ % was obtained in both planes. The overall performance of the hodoscope proved it to be well suited for the {\sc Adler} experiment to measure the high altitude muon flux.

nucl-ex↗

arXiv2001

A new airborne detector for atmospheric muons

The University of Oxford has started the design and development of the new experiment ADLER (Airborne Detector for Low Energy Rays). This apparatus will measure the cosmic-ray muon flux at an altitude of 10 - 13km. The detector should be flown by aircrafts on transatlantic routes crossing the magnetic equator to investigate the flux at different geomagnetic latitudes. The goal of the experiment is to obtain better constraints on the low energy atmospheric neutrino flux and the results will be of importance to the atmospheric neutrino anomaly.

hep-ex↗