Compact Mach-Zehnder interferometer Ce: YIG/SOI optical isolators

We demonstrate an optical isolator integrated with a silicon-on-insulator waveguide platform realized by the adhesive bonding of a Ce:YIG/SGGG die on top of a Mach-Zehnder interferometer (MZI). The design is based on the different nonreciprocal phase shifts (NRPS) experienced by both arms of the interferometer, which have different waveguide widths. Simulation of NRPS versus silicon waveguide width is shown for a few different benzocyclobutene bonding layer thicknesses for a particular silicon waveguide thickness and Ce: YIG/SGGG stack. Variations of NRPS as a function of MZI arm lengths with bonded stack on top of MZI are measured. Optical isolation of 11 dB is experimentally obtained for a device with a footprint of 1.5 mm x 4 mu m

New readout and data-acquisition system in an electron-tracking Compton camera for MeV gamma-ray astronomy (SMILE-II)

For MeV gamma-ray astronomy, we have developed an electron-tracking Compton camera (ETCC) as a MeV gamma-ray telescope capable of rejecting the radiation background and attaining the high sensitivity of near 1 mCrab in space. Our ETCC comprises a gaseous time-projection chamber (TPC) with a micro pattern gas detector for tracking recoil electrons and a position-sensitive scintillation camera for detecting scattered gamma rays. After the success of a first balloon experiment in 2006 with a small ETCC (using a 10$\times$10$\times$15 cm$^3$ TPC) for measuring diffuse cosmic and atmospheric sub-MeV gamma rays (Sub-MeV gamma-ray Imaging Loaded-on-balloon Experiment I; SMILE-I), a (30 cm)$^{3}$ medium-sized ETCC was developed to measure MeV gamma-ray spectra from celestial sources, such as the Crab Nebula, with single-day balloon flights (SMILE-II). To achieve this goal, a 100-times-larger detection area compared with that of SMILE-I is required without changing the weight or power consumption of the detector system. In addition, the event rate is also expected to dramatically increase during observation. Here, we describe both the concept and the performance of the new data-acquisition system with this (30 cm)$^{3}$ ETCC to manage 100 times more data while satisfying the severe restrictions regarding the weight and power consumption imposed by a balloon-borne observation. In particular, to improve the detection efficiency of the fine tracks in the TPC from $\sim$10\% to $\sim$100\%, we introduce a new data-handling algorithm in the TPC. Therefore, for efficient management of such large amounts of data, we developed a data-acquisition system with parallel data flow.Comment: 11 pages, 24 figure

The culdotomy two U procedure for vaginal ovarian cystectomy

When transvaginal removal of ovarian cysts is performed successfully, the procedure compares favorably with laparoscopy in terms of invasiveness. However, the approach into peritoneal cavity has been laborious. The objective was to evaluate feasibility of an ultrasound-guided culdotomy using a newly developed umbrella needle. New culdotomy was performed on 36 patients with ovarian cysts. Each cyst was directly punctured by the needle from vagina under ultrasound guidance. The vaginal walls on both sides of the needle were incised with an electric scalpel. Through the wound, cyst was exteriorized and enucleated. Preoperative characteristics of patients, outcome, operating time, blood loss, complications, and cyst histology were analyzed. Culdotomy was performed successfully in all cases. Operating time was less than 10 minutes and blood loss was less than 10 mL. There were no culdotomy-associated complications. Culdotomy assisted by ultrasound imaging and an umbrella needle is a simple, safe, and reliable method for vaginal ovarian cystectomy. © 2011 The Author(s)