ROBAST: Development of a ROOT-Based Ray-Tracing Library for Cosmic-Ray Telescopes and its Applications in the Cherenkov Telescope Array

We have developed a non-sequential ray-tracing simulation library, ROOT-based simulator for ray tracing (ROBAST), which is aimed to be widely used in optical simulations of cosmic-ray (CR) and gamma-ray telescopes. The library is written in C++, and fully utilizes the geometry library of the ROOT framework. Despite the importance of optics simulations in CR experiments, no open-source software for ray-tracing simulations that can be widely used in the community has existed. To reduce the dispensable effort needed to develop multiple ray-tracing simulators by different research groups, we have successfully used ROBAST for many years to perform optics simulations for the Cherenkov Telescope Array (CTA). Among the six proposed telescope designs for CTA, ROBAST is currently used for three telescopes: a Schwarzschild-Couder (SC) medium-sized telescope, one of SC small-sized telescopes, and a large-sized telescope (LST). ROBAST is also used for the simulation and development of hexagonal light concentrators proposed for the LST focal plane. Making full use of the ROOT geometry library with additional ROBAST classes, we are able to build the complex optics geometries typically used in CR experiments and ground-based gamma-ray telescopes. We introduce ROBAST and its features developed for CR experiments, and show several successful applications for CTA.Comment: Accepted for publication in Astroparticle Physics. 11 pages, 10 figures, 4 table

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Bit-Error and Soft-Error Resilient 7T/14T SRAM with 150-nm FD-SOI Process

Background: The aim of this study was to assess the accuracy of stress 99m technetium tetrofosmin myocardial perfusion imaging for the diagnosis of in stent stenosis (ISS). Methods: We studied 72 patients who underwent exercise or dobutamine stress 99m technetium tetrofosmin imaging, 0.9-0.5 years after percutaneous coronary interventions in which stents were deployed. Coronary angiography was performed within 3 months of the stress test. ISS was defined as ≥50% stenosis in a coronary segment with previous stenting. Significant coronary artery disease (CAD) was defined as ≥50% stenosis within or outside the stented coronary segment. Results: The stent was deployed in 1 coronary artery in 52 patients, and in 2 coronary arteries in 20 patients (a total of 92 detected in 42 (58%) patients (51 stents). Reversible perfusion abnormalities were present in 34 of patients

Comparison of early outcomes after primary stenting in Japanese patients with acute myocardial infarction between clopidogrel and ticlopidine in concomitant use with proton-pump inhibitor

SummaryBackgroundRecent studies have reported that concomitant use of clopidogrel with proton-pump inhibitors (PPIs) might decrease antiplatelet effects and increase the risk of adverse outcomes after coronary stenting. However, little is known about the difference between clopidogrel and ticlopidine in concomitant use with PPIs, especially within the Asian population.MethodsWe retrospectively analyzed 302 consecutive patients (248 males, mean age 66±12 years) undergoing primary stenting for acute myocardial infarction from July 2006 to June 2010. PPIs were administered to 92% (278/302) of the patients. The patients were divided into two groups on the basis of clopidogrel (clopidogrel group, n=187) or ticlopidine (ticlopidine group, n=91) with PPI. Their characteristics, medications, and 30-day clinical outcomes were examined.ResultsThere were no significant differences in 30-day major adverse cardiac events (cardiac death, non-fatal myocardial infarction, and definite stent thrombosis), bleeding events, and stroke between the two groups. The discontinuation of clopidogrel due to side effects was significantly less frequent than that of ticlopidine (1.1% vs 7.7%, p=0.003, respectively).ConclusionOur findings suggest that concomitant use of clopidogrel with PPIs might be safer than ticlopidine with PPIs in patients undergoing primary stenting for acute myocardial infarction

Prototyping Hexagonal Light Concentrators Using High-Reflectance Specular Films for the Large-Sized Telescopes of the Cherenkov Telescope Array

We have developed a prototype hexagonal light concentrator for the Large-Sized Telescopes of the Cherenkov Telescope Array. To maximize the photodetection efficiency of the focal-plane camera pixels for atmospheric Cherenkov photons and to lower the energy threshold, a specular film with a very high reflectance of 92-99% has been developed to cover the inner surfaces of the light concentrators. The prototype has a relative anode sensitivity (which can be roughly regarded as collection efficiency) of about 95 to 105% at the most important angles of incidence. The design, simulation, production procedure, and performance measurements of the light-concentrator prototype are reported.Comment: 21 pages, 14 figures, accepted for publication in JINS