arXiv subjects

M. R. Dickinson

Publications and source records attributed to M. R. Dickinson.

4 recordsLinked to original sources

arXiv2006

Nanometric laser trapping based on nanostructured substrates

Laser trapping near the surface of a nanostructured substrate is demonstrated. Stable microbubbles with radii of 1-20micrometers have been created and manipulated with sub-micron precision by a focused laser beam in an immersion oil covering arrays of pairs of gold nanopillars deposited on a glass substrate. The threshold for bubble creation and trapping characteristics depended on near-field coupling of nanopillars. The nanometric laser tweezers showed giant trapping efficiency of Q~50 for the trapped microbubbles.

physics.optics↗

arXiv1998

TeV gamma rays from PSR 1706-44

Observations made with the University of Durham Mark 6 atmospheric Cerenkov telescope confirm that PSR B1706-44 is a very high energy gamma-ray emitter. There is no indication from our dataset that the very high energy gamma-rays are pulsed, in contrast to the findings at < 20 GeV, which indicate that more than 80% of the flux is pulsed. The flux at E > 300 GeV is estimated to be (3.9 +/- 0.7 (statistical)) x 10^-11 cm^-2 s^-1.

astro-ph↗

arXiv1998

The Uuniversity of Durham Mark 6 Gamma Ray Telescope

The design, construction and operation of the University of Durham ground-based gamma ray telescope is discussed. The telescope has been designed to detect gamma rays in the < 200 GeV region and to achieve good discrimination between gamma ray and hadron initiated showers in the higher energy region (> 300 GeV). The telescope was commissioned in 1995 and a description of its design and operation is presented, together with a verification of the telescope's performance

astro-ph↗

arXiv1998

Centaurus X-3 - A Source of High Energy Gamma Rays

Centaurus X-3 is a well-studied high-mass accreting X-ray binary and a variable source of high energy gamma rays with energies from 100 MeV to 1 TeV. Previous results have suggested that the origin of the gamma rays is not the immediate vicinity of the neutron star but is sited in the accretion disc, perhaps in an accretion wake. The Durham Mark 6 gamma ray telescope has been used to measure the gamma ray flux from Centaurus X-3 with much higher sensitivity than previous ground-based measurements. The flux above ~ 400 GeV was measured to be (2 +/- 0.3) x 10^-11 cm^-2 s^-1 and appears constant over a period of 2 - 3 months. In 10 hours of observations there is no evidence for periodicity in the detected gamma rays at the X-ray spin period either from a site in the region of the neutron star, or from any other potential site in the orbit.

astro-ph↗