نتایج جستجو برای: photocathode
تعداد نتایج: 844 فیلتر نتایج به سال:
An efficient, stable and scalable hybrid photoelectrode for visible-light-driven H2 generation in an aqueous pH 9.2 electrolyte solution is reported. The photocathode consists of a p-type Si substrate layered with a Ti and Ni-containing composite film, which acts as both a protection and electrocatalyst layer on the Si substrate. The film is prepared by the simple drop casting of the molecular ...
Amorphous Si thin film based photocathodes with high photovoltage for efficient hydrogen production.
An amorphous Si thin film with TiO2 encapsulation layer is demonstrated as a highly promising and stable photocathode for solar hydrogen production. With platinum as prototypical cocatalyst, a photocurrent onset potential of 0.93 V vs RHE and saturation photocurrent of 11.6 mA/cm(2) are measured. Importantly, the a-Si photocathodes exhibit impressive photocurrent of ~6.1 mA/cm(2) at a large pos...
We have observed Cherenkov rings from minimum-ionizing particles using a low-pressure, parallel-plate pad-chamber with a cesium-iodide solid photocathode . This detector is blind to minimum-ionizing particles, and sensitive to Cherenkov photons of wavelengths 170-210 rim. An average of 5 photoelectrons per Cherenkov ring were detected using a 2-cm-thick radiator of liquid C6F14 . This paper rep...
X-ray framing cameras, employing microchannel plates (MCPs) for detection and signal amplification, play a key role in research in high-energy-density physics. These instruments convert radiographic x-rays into electrons produced by plasma during such experiments into electrons that are amplified in the channels and then detected by a phosphor material. The separation of detection from signal a...
The SLAC polarized electron source employs a photocathode DC high voltage gun with a loadlock and a YAG pumped Ti:sapphire laser system for colliding beam experiments or a flash lamp pumped Ti:sapphire laser for fixed target experiments. It uses a thin, strained GaAs(100) photocathode, and is capable of producing a pulsed beam with a polarization of ≥80% and a peak current exceeding 10 A. Its o...
The Cornell ERL Photoinjector prototype has recently demonstrated successful operation at 20 mA for 8 hours using a bi-alkali photocathode grown on a Si substrate. The photocathode film was grown off center, and remained relatively undamaged; however, upon removal from the gun, the substrate at the gun electrostatic center displayed significant visible damage. Here we will describe not only the...
The combination of enzymes with semiconductors enables the photoelectrochemical characterization of electron-transfer processes at highly active and well-defined catalytic sites on a light-harvesting electrode surface. Herein, we report the integration of a hydrogenase on a TiO2-coated p-Si photocathode for the photo-reduction of protons to H2. The immobilized hydrogenase exhibits activity on S...
Photocathode is one of the most important components in the next-generation accelerators, especially based on linear accelerators. Photocathode performance depends not only on electronic state in its bulk material but also on the surface condition. CsK2Sb multi-alkali photocathode is a candidate for the high brightness electron source because of its high quantum efficiency by green laser and it...
One of the 21 century scientific frontiers is to explore the molecule structure transition on the femtosecond time scale. X-ray free electron laser (XFEL) is one of the tools now under development for investigating femto-second structure transition. We are proposing an alternative technique – femto-second electron diffraction based on a photocathode RF gun. We will present a design of a kHz fem...
The slice transverse emittance of an electron beam is of critical significance for an x-ray FEL. In a photocathode RF gun, the slice transverse emittance is not only determined by the emission process, but also influenced strongly by the nonlinear space charge effect. In this paper, we study the slice transverse emittance evolution in a photocathode RF gun using a simple model that includes eff...
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