The Ultra-Fast Flash Observatory (UFFO), which will be launched onboard theLomonosov spacecraft, contains two crucial instruments: UFFO BurstAlert & Trigger Telescope (UBAT) for detection and localization of Gamma-Ray Bursts(GRBs) and the fast-response Slewing Mirror Telescope (SMT) designed for the observationof the prompt optical/UV counterparts. Here we discuss the in-space calibrations of theUBAT detector and SMT telescope. After the launch, the observations of the standard X-raysources such as pulsar in Crab nebula will provide data for necessary calibrations ofUBAT. Several standard stars will be used for the photometric calibration of SMT. Thecelestial X-ray sources, e.g. X-ray binaries with bright optical sourcesin their close angular vicinity will serve for the cross-calibration of UBAT and SMT.

The Ultra-Fast Flash Observatory (UFFO) Pathfinder for Gamma-Ray Bursts (GRBs) consistsof two telescopes. The UFFO Burst Alert & Trigger Telescope (UBAT) handles thedetection and localization of GRBs, and the Slewing Mirror Telescope (SMT) conducts themeasurement of the UV/optical afterglow. UBAT is equipped with an X-ray detector, analogand digital signal readout electronics that detects X-rays from GRBs and determines thelocation. SMT is equipped with a stepping motor and the associated electronics to rotatethe slewing mirror targeting the GRBs identified by UBAT. First the slewing mirror pointsto a GRB, then SMT obtains the optical image of the GRB using the intensified CCD and itsreadout electronics. The UFFO Data Acquisition system (UDAQ) is responsible for theoverall function and operation of the observatory and the communication with the satellitemain processor. In this paper we present the design and implementation of the electronicsof UBAT and SMT as well as the architecture and implementation of UDAQ.

The UFFO (Ultra-Fast Flash Observatory) is a GRB detector on board the Lomonosovsatellite, to be launched in 2013. The GRB trigger is provided by an X-ray detector,called UBAT (UFFO Burst Alarm & Trigger Telescope), which detects X-rays from the GRBand then triggers to determine the direction of the GRB and then alerts the Slewing MirrorTelescope (SMT) to turn in the direction of the GRB and record the optical photon fluxes.This report details the calibration of the two components: the MAPMTs and the YSO crystalsand simulations of the UBAT. The results shows that this design can observe a GRB within afield of view of ±35° and can trigger in a time scale as short as 0.2 – 1.0 safter the appearance of a GRB X-ray spike.

The Ultra-Fast Flash Observatory (UFFO) is a space mission to detect the early moments of an explosion from Gamma-ray bursts (GRBs), thus enhancing our understanding of the GRB mechanism. It consists of the UFFO Burst & Trigger telescope (UBAT) for the recognition of GRB positions using hard X-ray from GRBs. It also contains the Slewing Mirror Telescope (SMT) for the fast detection of UV-optical photons from GRBs. It is designed to begin the UV-optical observations in less than a few seconds after the trigger. The UBAT is based on a coded-mask X-ray camera with a wide field of view (FOV) and is composed of the coded mask, a hopper and a detector module. The SMT has a fast rotatable mirror which allows a fast UV-optical detection after the trigger. The telescope is a modified Ritchey-Chrétien telescope with the aperture size of 10 cm diameter, and an image intensifier readout by CCD. The UFFO pathfinder is scheduled to launch into orbit on 2012 June by the Lomonosov spacecraft. It is a scaled-down version of UFFO in order to make the first systematic study of early UV/optical light curves, including the rise phase of GRBs. We expect UBAT to trigger ~44 GRBs/yr and expect SMT to detect ~10 GRBs/yr.

In this work, we have conducted a systematic investigation of leakage current and electrical breakdown of plasma enhanced chemical vapor deposited (PECVD) silicon nitride, both for planar films and deposited films on the vertical sidewall for the application of the vertical thin film transistors. The thickness evolution of physical properties and electrical characteristics of silicon nitride films in the range of 50 to 300 nm are investigated. Electrical breakdown strength for 150-300nm thick films was approximately 7 MV/cm, whereas the value dropped to ~3MV/cm for 50nm thick films deposited under the same process conditions. It is shown that the early failure of the thin nitride is accompanied by the increase of the pinholes number. For the vertical thin film transistors, the experimental result shows the reliability and leakage current of the gate dielectric depends on the step coverage of the silicon nitride film on the vertical sidewall.

Metal-insulator-semiconductor (MIS) capacitors have been fabricated on n-type GaN (0001) films using thermally grown Ga2O3, remote plasma enhanced chemical vapor deposited (RPECVD) SiO2, and molecular beam epitaxy (MBE) AIN as the gate insulator and Al as the gate electrode. Each GaN epitaxial layer was grown by organometallic chemical vapor deposition (OMCVD) on a 6H-SiC(0001) substrate on which was previously deposited a 1000Å buffer layer of AIN. Nitrogen-free polycrystalline films of Ga2O3 were grown on the GaN. Capacitancevoltage measurements of capacitors fabricated from this oxide showed distinct depletion and accumulation regions with significant leakage. The AIN and SiO2 capacitors demonstrated better electrical characteristics than the Ga2O3 because of lower leakage. The RPECVD SiO2/GaN heterostructures, in particular, showed good agreement with the curves calculated for an ideal oxide and a small amount of hysteresis.

Thin films of AlxGa1−xN (0.05 ≤ x ≤ 0.96) having smooth surfaces were deposited directly on both vicinal and on-axis 6H-SiC(0001) substrates. Cross-sectional TEM of Al0.13Ga0.87N revealed stacking faults near the SiC/Nitride alloy interface and numerous threading dislocations. EDX, AES and RBS were used to determine the compositions, which were paired with their respective CL near band-edge emission energies. A negative bowing parameter was determined. The CL emission energies were similar to the bandgap energies obtained by SE. FE-AES of the initial growth of Al0.2Ga0.8N revealed an aluminum rich layer near the interface. N-type (silicon) doping was achieved for AlxGa1−xN for 0.12 ≤ x ≤ 0.42. Al0.2Ga0.8N/GaN superlattices were fabricated with coherent interfaces. Additionally, HEMT structures using an AlN/GaN/AlN buffer structure were fabricated.

Thermodynamic functions of Co-Si and Au-Si systems were studied. The validity of these functions were confirmed by successfully calculating phase diagrams. It was revealed that the composition of the first nucleated compound is close to the concentration of the minimum free energy of the liquid alloy with respect to the two solid components (ΔG) of the binary systems. In addition, the minimum ΔG concentration was found to be located by interpolating the portion of the liquidus, where the liquid alloy is in equilibrium with the two solid constituents, into the central region of the diagram where compounds exist. The minimum ΔG concentration of other silicide and germanide systems were estimated by the suggested interpolation method. A new model for predicting the first nucleated compound in silicide as well as germanide systems was proposed based on the findings.

Rapid thermal annealing (RTA) was applied to anneal polycrystalline CdTe thin films evaporated on CdS/ITO substrate and the effects of rapid thermal annealing temperatures and gas environments were studied. X-ray diffractometer (XRD), X-ray photoelectron spectroscopy(XPS), energy dispersive X-ray spectroscopy(EDX), cross-sectional transmission microscopy(TEM), and micro-EDX in TEM were used to characterize physical and chemical properties of rapid thermal annealed CdTe thin films. Complete CdTe/CdS photovoltaic cells were fabricated and I-V characteristics of these cells were measured under the illumination. Results showed that the bulk composition of CdTe remained stoichiometric to 550°C in the air environment and surface composition became Cd-rich. Cross-sectional TEM and micro-EDX showed columnar grains and micro-twins remained even after RTA, however, sulfur content in rapid thermal annealed CdTe caused by sulfur diffusion from CdS during the annealing was much smaller than that by furnace annealing. Among the investigated RTA temperatures and gas environments, the cell made with CdTe annealed at 550°C in the air showed the best solar energy conversion efficiency.

Titanium silicides were prepared by coevaporation of Ti and Si on Si substrates at intermediate substrate temperatures followed by high temperature annealing. Depending on the deposition conditions, transmission electron diffraction analyses revealed two different halo patterns from the as-deposited samples. Variations in the deposition conditions included substrate temperature, deposition rate, and film thickness. Radial distribution functions were calculated to estimate the short range ordering of the amorphous phases. The interatomic distances of all the titanium silicide compounds were also calculated in order to compare them with the atomic ordering of amorphous phases. Phase transition from these amorphous phases to the first crystalline silicide is discussed in terms of kinetic variations as well as the atomic ordering.