Rene Hudec: AXRO 10 years: Introduction and Historical Background
AXRO 10 years: Introduction and Historical Background will be shortly presented and discussed
Paola Zuppella: Soft x-ray and EUV metrology for space applications
Przemyslaw Wachulak: Laser plasma EUV and SXR source based on a double stream gas puff target for testing and metrology applications of EUV/SXR optics: previous experiments and future plans.
In the talk I would like to present applications of a compact, pulsed laser plasma EUV and SXR source, based on a double stream gas puff target, for testing and metrology of EUV and SXR mirrors. Such optics, most often used in short wavelength optical systems, is also very important nowadays for astronomical applications. Additionally, future plans will be presented, related to the development of a dedicated system, which will be based on such source, for diagnostics of grazing incidence more... mirrors in the EUV and SXR spectral region.
Bernd Aschenbach: The maximal spin of an accreting black hole - the ´Thorne´ limit and the ´Aschenbach´ effect
The Kip Thorne limit for the spin of an accreting black is (the Kerr parameter) a=0.998, which is due to photons carrying away angular momentum. The Aschenbach effect describes a discovery that for the Kerr metric the otherwise monotonous increase of the velocity of a particle orbiting a spinning black hole with decreasing orbital radius is broken for a>0.9959. The orbital velocity runs through a decline and a minimum until it rises again, with decreasing orbital radius. Because of the more... similarity of these two limiting values of the spin I conjecture that the inner part of the accretion disk of such highly spinning black holes is unstable, with the result of outbursts and flares, which can come quasiperiodically with the expected epicyclic frequencies.
Zhanshan Wang: Development of soft X-ray telescope optics for EP mission
The Einstein Probe (EP) mission, which aims at discovering transients and monitoring variable objects in 0.5-4 keV X-rays, is a small scientific satellite dedicated to time-domain high-energy astrophysics. EP will employ a large instantaneous field-of-view (60°×60°) X-ray telescope (WXT), along with moderate spatial resolution (FWHM ~5) and energy resolution. It will also carry a follow-up observation X-ray telescope (FXT) with a smaller field-of-view - capable of much larger light-collecting power and better energy resolution than the main survey telescope. In more... this presentation, we present the optical design and simulations of the FXT, which include the optimized structure parameters of the FXT and its focusing capabilities. The FXT will employ conically-approximated Wolter-I geometry with a focal length of 2 m, and thin glass mirrors with 100 mm in length and 0.3 mm in thickness, which consists of 66 shells tightly-nested with the diameters range from 80 mm to 250 mm. Based on such a kind of configuration, the effective area can be 245 cm2 at 1 keV and 196 cm2 at 4 keV, with an image quality to be approximately 55 in half-power diameter (HPD), and with a field of view (FOV) to be approximately 30, theoretically. The segmented mirrors that form these layers are formed by thermally slumping glass substrates coated with some metal layers for enhanced reflectivity in the interested energy region. In order to force the overall shape of the nominally cylindrical substrates to the appropriate conic form, an over-constraint method was used to assemble the mirrors to a telescope prototype. We will present optical performance on the EP optics and the current status of the telescope.