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The extremely low dark current of silicon carbide (SiC) detectors, even after high-fluence irradiation, was utilized to develop a beam monitoring system for a wide range of particle rates, i.e., from the kHz to the GHz regime. The system is…
An international team is currently investigating the best way to use Higher Order Modes (HOM) for beam diagnostics in 3.9 GHz cavities. HOMs are excited by charged particles when passing through an accelerating structure. Third harmonic…
Hybrid laser plasma radiofrequency (RF) acceleration architectures signify a promising advancement in addressing the stability challenges associated with traditional laser wakefield accelerators. A thorough theoretical and numerical…
FLASH is the first free electron laser user facility operating in the vacuum ultraviolet and soft x-ray wavelength range. Many user experiments require knowledge of the spatial and temporal coherence properties of the radiation. In this…
We present a heterodyne stabilized cavity-based interferometer scheme that can serve as a compact and high-sensitivity displacement sensor with a fringe-scale operating range. The technique, in principle, can reach a sub-femtometer noise…
A quasi-optical (QO) test bench was designed, simulated, and calibrated for characterizing S-parameters of devices in the 220-330 GHz (WR-3.4) frequency range, from room temperature down to 4.8 K. The devices were measured through vacuum…
This paper presents the design, fabrication, and characterization of broadband liquid crystal (LC) reconfigurable intelligent surfaces (RIS) operating around 60 GHz and scaling up to 750 radiating elements. The RISs employ a delay line…
Studies of the crab cavities at KEKB revealed that the RF phase could shift by up to 50o within ~50 us during a quench; while the cavity voltage is still at approximately 75% of its nominal amplitude. If such a failure were to occur on the…
We report on an approach to produce quasi continuous-wave (cw) electron beams with an average beam current of milliamperes and a mean beam energy of a few MeV in a pulsed RF injector. Potential applications are in the planned laboratory…
A progogype 5-GHz 500-kW CW klystron (model E3762 provided by Toshiba Electron Tubes & Devices Co. Ltd.) has been operating as the RF source for the lower hybrid current drive (LHCD) system in the KSTAR tokamak. In order to investigate how…
We consider several ILC energy upgrade paths beyond 1 TeV depending on the needs of high energy physics. Parameters for four scenarios will be pre-sented and challenges discussed. 1. From 1 TeV to 2 TeV based on: A. Gradient advances of Nb…
Waveform feature is one of the requirements for the FRIB LLRF controllers. It is desired that the LLRF con-trollers store the internal data (e.g. the amplitude and phase information of forward/reverse/cavity signals) for at least one second…
Precisely stabilizing laser frequency is crucial for advancing laser technology and unlocking the full potential of various quantum technologies. Here, we propose a compact device for stabilizing frequency of a semiconductor laser through…
The 2nd generation VLTI instrument GRAVITY is a two-field infrared interferometer operating in the K band between 1.97 and 2.43 $\mu$m with either the four 8 m or the four 1.8 m telescopes of the Very Large Telescope (VLT). Beams collected…
The Low-Level RF (LLRF) control circuits of linear accelerators (LINACs) are conventionally realized with heterodyne based architectures, which have analog RF mixers for up and down conversion with discrete data converters. We have…
Frequency-stabilized mid-infrared lasers are valuable tools for precision molecular spectroscopy. However, their implementation remains limited by complicated stabilization schemes. Here we achieve optical self-locking of a quantum cascade…
We have identified a novel phase stability mechanism from the intracavity field-induced self-organization of a fast-moving molecular beam into travelling molecular packets in the bad cavity regime, which is then used to decelerate the…
Ultraviolet (UV) diode lasers are widely used in many photonics applications. But their frequency stabilization schemes are not as mature as frequency-doubling lasers, mainly due to some limitations in the UV spectral region. Here we…
We report on the development of a trapped-ion, microwave frequency standard based on the 12.6 GHz hyperfine transition in laser-cooled ytterbium-171 ions. The entire system fits into a 6U 19-inch rack unit ($51\times49\times28$ cm) and…
The FLASHForward experimental facility is a high-performance test-bed for precision plasma-wakefield research, aiming to accelerate high-quality electron beams to GeV-levels in a few centimetres of ionised gas. The plasma is created by…