Head motion correction for jPET-D4 Muraishi, H.; Hasegawa, T.; Yoda, K. ...
IEEE Symposium Conference Record Nuclear Science 2004,
2004, Letnik:
4
Conference Proceeding
We propose a new method of head motion tracking for positron emission tomography (PET) brain imaging. This method uses one optical camera and one solid marker, differing from the conventional method, ...which uses two or more cameras and markers (e.g. the POLARIS system). We expect this to be useful for jPET-D4, whose patient port is long and small. We present the principle of the head motion measurement and show the results of preliminary experiments.
The Cherenkov telescope of the CANGAROO II project will start operation in 1999 in Woomera, South Australia, with a 7 m aperture using 60 plastic mirrors. The telescope, which can potentially be ...extended to a 10 m aperture, will be used to observe gamma-ray sources with an energy threshold of the order of 100 GeV in the southern sky.
Observations of the PSR B1259-63/SS 2883 binary system using the CANGAROO-II Cerenkov telescope are reported. This nearby binary consists of a 48 ms radio pulsar in a highly eccentric orbit around a ...Be star and offers a unique laboratory to investigate the interactions between the outflows of the pulsar and Be star at various distances. It has been pointed out that the relativistic pulsar wind and the dense mass outflow of the Be star may result in the emission of gamma rays up to TeV energies. We have observed the binary in 2000 and 2001, approx47 and approx157 days after the 2000 October periastron. Upper limits at the 0.13-0.54 crab level are obtained. A new model calculation for high- energy gamma-ray emission from the Be star outflow is introduced, and the estimated gamma-ray flux, considering bremsstrahlung, inverse Compton scattering, and the decay of neutral pions produced in proton-proton interactions, is found to be comparable to the upper limits of these observations. Comparing our results with these model calculations, we constrain the mass-outflow parameters of the Be star.
SS433, located at the center of the supernova remnant W50, is a close proximity binary system consisting of a compact star and a normal star. Jets of material are directed outwards from the vicinity ...of the compact star symmetrically to the east and west. Non-thermal hard X-ray emission is detected from lobes lying on both sides. Shock accelerated electrons are expected to generate VHE gamma rays through the inverse-Compton process in the lobes. Observations of the western X-ray lobe region of SS433/W50 system have been performed to detect VHE gamma rays using the 10
m CANGAROO-II telescope in August and September, 2001, and July and September, 2002. The total observation times are 85.2
h for ON source, and 80.8
h for OFF source data. No significant excess of VHE gamma rays has been found at three regions of the western X-ray lobe of SS433/W50 system. We have derived 99% confidence level upper limits to the fluxes of gamma rays and have set constraints on the strengths of the magnetic fields assuming the synchrotron/inverse-Compton model for the wide energy range of photon spectrum from radio to TeV. The derived lower limits are
4.3
μ
G for the center of the brightest X-ray emission region and
6.3
μ
G for the far end from SS433 in the western X-ray lobe. In addition, we suggest that the spot-like X-ray emission may provide a major contribution to the hardest X-ray spectrum in the lobe.
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