Change search
ReferencesLink to record
Permanent link

Direct link
Performance Studies and Star Tracking for PoGOLite
KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
2010 (English)Doctoral thesis, monograph (Other academic)
Abstract [en]

PoGOLite is a balloon-borne experiment, which will study polarized soft γ-ray emissionfrom astrophysical targets in the 25-80 keV energy range by applying well-typephoswich detector technology. Polarized γ-rays are expected from a wide variety of sources including rotation-powered pulsars, accreting black holes and neutron stars,and jet-dominated active galaxies. Polarization measurements provide a powerfulprobe of the γ-ray emission mechanism and the distribution of magnetic and radiation fields around the source. The polarization is determined using Compton scattering and photoelectric absorption in an array of 217 plastic scintillators. The sensitive detector is surrounded by a segmented Bismuth Germanium Oxide (BGO) anticoincidence shield. The function of this shield is to reduce backgrounds from charged cosmic rays, primary and atmospheric γ-rays, and atmospheric and instrumenta lneutrons. The anticoincidence shield consists of 427 BGO crystals with three different geometries. The characteristics of the BGO crystals of the bottom anticoincidence shield have been studied with particular focus on the light yield.The maiden flight of PoGOLite will be with a reduced detector volume “pathfinder” instrument. The flight, lasting about 24 hours, is foreseen from Esrange, Sweden in August 2010. The performance of the pathfinder has been studied using computer simulations. The effect of atmospheric attenuation, both on the signal of theastronomical target and on the background, are studied. These allow an observationstrategy to be developed for the forthcoming flight. A polarization analysis method is described and applied to an observation example. The method sets anupper limit on the accuracy with which the polarimeter will be able to detect polarization the angle and degree. The PoGOLite polarimeter has a relatively small field of view (2.4×2.4) which must be kept aligned to objects of interest on the sky. A star tracker forms part of the attitude control system. The star trackersystem comprises a CCD camera, a lens, and a baffle system. Preliminary studiesof the star identification performance are presented and are found to be compatible with the environment around the Crab, which is the main observational target for the first flight.

Place, publisher, year, edition, pages
Stockholm: KTH , 2010. , viii, 185 p.
Trita-FYS, ISSN 0280-316X ; 2010:24
Keyword [en]
polarization, pulsars, x-ray, PoGOLite
National Category
Subatomic Physics
URN: urn:nbn:se:kth:diva-13015ISBN: 978-91-7415-641-6OAI: diva2:320226
Public defence
2010-06-04, FB52, AlbaNova Universitetscentrum, Roslagstullsbacken 21, Stockholm, 10:42 (English)
QC20100629Available from: 2010-05-25 Created: 2010-05-24 Last updated: 2010-06-29Bibliographically approved

Open Access in DiVA

fulltext(8875 kB)237 downloads
File information
File name FULLTEXT01.pdfFile size 8875 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Marini Bettolo, Cecilia
By organisation
Particle and Astroparticle Physics
Subatomic Physics

Search outside of DiVA

GoogleGoogle Scholar
Total: 237 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 437 hits
ReferencesLink to record
Permanent link

Direct link