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P. Deines-Jones

Publications and source records attributed to P. Deines-Jones.

4 recordsLinked to original sources

An X-ray Polarimeter for Constellation-X

Polarimetry remains a largely unexploited technique in observational X-ray astronomy which could provide insight in the study of the strong gravity and magnetic fields at the core of the Constellation-X observational program. Adding a polarization capability to the Constellation-X instrumentation would be immensely powerful. It would make Constellation the first space observatory to simultaneously measure all astrophysically relevant parameters of source X-ray photons; their position (imaging), energy (spectroscopy), arrival time (timing), and polarization. Astrophysical polarimetry requires sensitive well-calibrated instruments. Many exciting objects are extra-galactic (i.e. faint) and may have small polarization. Recent advances in efficiency and bandpass make it attractive to consider a polarimetry Science Enhancement Package for the Constellation-X mission.

astro-ph

The imaging X-ray detector for Lobster-ISS

Lobster-ISS is a revolutionary astrophysical X-ray all-sky monitor scheduled for deployment as an attached payload on the International Space Station (ISS) in 2009. Using a new wide field-of-view focusing optic, Lobster-ISS provides an order-of-magnitude improvement in the sensitivity of all-sky monitors in the soft X-ray band (0.1-3.0 keV). This lobster-eye optic presents unique challenges to the imaging X-ray detector at its focus. Micro-patterned imaging proportional counters, with thier mechanical simplicity and high performance, are the most practical means of meeting the requirements. We describe our design for the Lobster-ISS imaging detector based on direct-imaging micro-well proportional counters and the expected performance.

physics.ins-det

X-ray polarimetry with an active-matrix pixel proportional counter

We report the first results from an X-ray polarimeter with a micropattern gas proportional counter using an amorphous silicon active matrix readout. With 100% polarized X-rays at 4.5 keV, we obtain a modulation factor of 0.33 +/- 0.03, confirming previous reports of the high polarization sensitivity of a finely segmented pixel proportional counter. The detector described here has a geometry suitable for the focal plane of an astronomical X-ray telescope. Amorphous silicon readout technology will enable additional extensions and improvements.

physics.ins-det

Charged particle production in the Pb+Pb system at 158 GeV/c per nucleon

Charged particle multiplicities from high multiplicity central interactions of 158 GeV/nucleon Pb ions with Pb target nuclei have been measured in the central and far forward projectile spectator regions using emulsion chambers. Multiplicities are significantly lower than predicted by Monte Carlo simulations. We examine the shape of the pseudorapidity distribution and its dependence on centrality in detail.

hep-ex