Characterization of silicon pore optics for the NewAthena X-ray observatory in the PTB laboratory at BESSY II.

The New Advanced Telescope for High ENergy Astrophysics (NewAthena) will be the largest space-based X-ray observatory ever built. It will have an effective area above 1.1 m2 at 1 keV, which corresponds to a polished mirror surface of about 300 m2 due to the grazing incidence. As such a mirror area is not achievable with an acceptable mass even with nested shells, silicon pore optics (SPO) technology will be utilized. In the PTB laboratory at BESSY II, two dedicated beamlines are in use for their characterization with monochromatic radiation at 1 keV and a low divergence well below 2 arcsec: the X-ray Pencil Beam Facility (XPBF 1) and the X-ray Parallel Beam Facility (XPBF 2.0), where beam sizes up to 8 mm × 8 mm are available while maintaining low beam divergence. This beamline is used for characterizing mirror stacks and controlling the focusing properties of mirror modules (MMs) - consisting of four mirror stacks - during their assembly at the beamline. A movable CCD based camera system 12 m from the MM registers the direct and the reflected beams. The positioning of the detector is verified by a laser tracker. The energy-dependent reflectance in double reflection through the pores of an MM with an Ir coating was measured at the PTB four-crystal monochromator beamline in the photon energy range 1.75 keV to 10 keV, revealing the effects of the Ir M edges. The measured reflectance properties are in agreement with the design values to achieve the envisaged effective area.

Dynamic anal endosonography may challenge defecography for assessing dynamic anorectal disorders: results of a prospective pilot study.

BACKGROUND AND STUDY AIMS: The diagnosis of anorectal dynamic disorders and perineal insufficiency has been mainly based up to now on the use of defecography. Here, we performed a prospective blinded study to evaluate the accuracy of a new procedure, dynamic anorectal endosonography (DAE), by comparing it with defecography. PATIENTS AND METHODS: A total of 43 women (mean age 53), presenting with outlet obstruction, were prospectively enrolled in our study. The DAE was performed with a 7.5-Mhz linear probe (Toshiba, Tokyo, Japan) with basal and straining recordings. None of the DAE or defecography operators was informed about the results of the respective other investigation. RESULTS: Defecography showed a descending perineum in 29 patients (68%), a rectocele in 25 patients (58%), and a rectal intussusception in eight patients (18%). The rate of concordance between the diagnosis of descending urinary bladder at DAE and descending perineum at defecography was 35/43 (80%), and that between the descending puborectal muscle at DAE and descending perineum at defecography was 40/43 (93 %). The rates of concordance between DAE and defecography for the diagnosis of rectocele and rectal intussusception were 27/43 patients (57%) and 34/43 patients (80%), respectively. In the last 15 patients, the DAE technique was adapted in order to improve the accuracy for diagnosing rectocele by filling the rectum with water. This improved sensitivity from 36 to 86% and accuracy from 57 to 87%. CONCLUSIONS: DAE is a new imaging approach to anorectal dynamic disorders, providing a highly reliable means of diagnosing perineal insufficiency as well as rectocele. DAE should be substituted for previous methods since it makes it possible at the same time to assess the anal sphincters and to avoid pelvic irradiation.