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This study explores the physics of vacuum rf breakdowns in high gradient mm-wave accelerating structures. We performed a series of experiments with 100 GHz and 200 GHz metallic accelerating structures, at the Facility for Advanced Accelerator Experimental Tests (FACET) at the SLAC National Accelerator Laboratory.
Diffusion MRI is widely used for the clinical examination of a variety of diseases of the nervous system. However, clinical MRI scanners are mostly capable of magnetic field gradients in the range of 20–80 mT/m and are thus limited in the detection of small tissue structures such as determining axon diameters. The availability of high …
SUMMARY. The high-gradient studies with single-cell cavities for ILC continue at Cornell. A new record gradient of 59 MV/m was achieved in a new 60 mm aperture re-entrant cavity. The peak surface magnetic field reached also a record value of 2065 Oe.
A major factor that limits high accelerating gradients in normal conducting accelerating structures is the RF breakdown, which is an avalanche electron emission process that abruptly changes the structure's RF properties and can induce irreversible damages to the surfaces. 1 Intensive experimental and theoretical efforts have been …
The main goals were to study the high gradient behavior and to evaluate the maximum gradient reached in 3 and 5.7 GHz structures to direct the design of medical accelerators based on high gradient linacs. This paper summarizes the results of the high power tests of 3.0 and 5.7 GHz single-cell cavities.
A high-gradient test is demonstrated, including the conditioning history, the highest achieved gradient, and the spatial distribution of breakdown inside the structure. …
Low, intermediate, and high gradients were present in 43.3%, 38.1%, and 18.6% of the population, respectively. ... low statistical power may partly explain the lack of association of clinical outcomes and elevated echocardiographic gradients, this study suggests another possible reason. The opposing association of low (<10 mm Hg) and ...
Pure oxygen-free high-conductivity copper is a widely used material for manufacturing accelerating cavities working at room temperature. Several studies attempted to explain limitations associated with the maximum allowed field gradients and the behaviour of vacuum RF breakdown in copper accelerating structures through …
High pressure water rinsing (HPR) after bulk EP and before 600°C furnace heat treatment improves cleaning and avoids burning chemical residuals into surface. A major enhancement of our cavity gradient studies is added instrumentation of T-mapping and high-resolution optical inspection (Fig. 1). We will give some examples of
High gradient magnetic separation (HGMS) is an important separation technique based on susceptibility variance of particles, and has been widely applied in many fields: minerals processing, water purification, extractive metallurgy and biochemical activities. ... In this study, a novel method termed high gradient magnetic separation …
Research in ultrahigh magnetic field strength combined with ultrahigh and ultrafast gradient technology has provided enormous gains in sensitivity, resolution, and contrast for neuroimaging. This article provides an overview of the technical advantages and challenges of performing clinical neuroimaging studies at ultrahigh magnetic field …
Nevertheless, we anticipate that the availability of such high gradient strengths may alleviate the bias seen in axon diameter mapping studies performed to date in human MRI scanners, including the original Connectome MRI scanner, and we look forward to further advances in gradient technology that may help to resolve such biases.
The ACCIL will have a 35 MV/m real-estate accelerating gradients that became possible to achieve with the development of novel S-band high-gradient structures, capable of providing 50 MV/m ...
Recent studies of copper cavities have been shown that harder copper ... high gradient S-band photocathode RF gun by INFN-LNF, Italy. e RF gun was successfully tested up to a eld
study of this cavity through high-gradient testing. B. Test stand The setup of the high-gradient test for DR cavity No. 2 is shown in Fig. 3. We used a 1.2-MW continuous-wave klystron as a high-power source together with a four-port circulator to protect this klystron. High rf power was fed into the cavity through a coaxial-type high-power ...
Introduction. There has been a striking evolution in the role of the cardiac catheterization laboratory over the past decades. 1 In the 1950s and 1960s, hemodynamic assessment in the cardiac catheterization …
This paper reviews the current state-of-the-art in understanding the phenomena of ultra-high vacuum radio-frequency (rf) breakdown in accelerating …
In this study, we used cut-off value of AVA CT < 1.2 cm 2 as this value was suggested for severe AS in a previous study 12. In high-gradient severe AS group, approximately 10% (43/438) of patients ...
High gradient studies High gradient studies requires: • High Power RF devices and related technologies • Accelerator structure developments and related arts We will present a brief review of the state of the art in these topics then move to the planned work. 12/21/2005 18
The high-power performance of two more 60cm structures will be measured in 2005. These studies are expected to provide benchmark performance data of accelerator structures …
Connectome 2.0: Developing the next-generation ultra-high gradient strength human MRI scanner for bridging studies of the micro-, meso- and macro-connectome August 2021 NeuroImage 243:118530
Thermography and Temperature Gradient Studies Policy Number: 6.01.12 Last Review: 11/2013 Origination: 11/2002 Next Review: 11/2014 ... and locating high undescended testicles. The American Chiropractic Association suggests that high-resolution infrared imaging is of value in the
A novel high-gradient accelerating structure with low phase velocity, v / c = 0.38, has been designed, manufactured and high-power tested.The structure was designed and built using the methodology and technology developed for CLIC 100 MV / m high-gradient accelerating structures, which have speed of light phase velocity, but adapts …
High-resolution 3D object generation remains a challenging task primarily due to the limited availability of comprehensive annotated training data. Recent …
High frequency linear collider schemes envisage the use of rather high accelerating gradients: 50 to 100 MV/m for X-band and 80 MV/m for CLIC. Because these gradients are well above those commonly used in accelerators, high gradient studies of high frequency structures have been initiated and test facilities have been constructed at …
High frequency linear collider schemes envisage the use of rather high accelerating gradients: 50 to 100 MV/m for X-band and 80 MV/m for CLIC. Because these gradients are well above those commonly used in accelerators, high gradient studies of high frequency structures have been initiated and test facilities have been constructed at KEK [1],
In the scope of a decade-long collaboration between SLAC, INFN-Frascati, and KEK on the development of innovative high-gradient structures, this particular study focuses on the technological developments directed to show the viability of novel welding techniques. Two novel X-band accelerating structures, made out of hard copper, were …
High magnetic field gradient is a crucial factor in HGMS process which can be described as a separation process or a deep-bed filtration process in which a magnetic matrix is magnetized and used to bundle the external magnetic field in its vicinity to generate high magnetic field gradient [12].In the presence of strong magnetic field, …
A novel high-gradient accelerating structure with low phase velocity, v=c 1⁄4 0.38, has been designed, manufactured and high-power tested. The structure was designed and built using the methodology … Expand
Vacuum radio-frequency (rf) breakdown is one of the major factors that limit operating accelerating gradients in rf particle accelerators. The occurrence of rf breakdowns was shown to be probabilistic, and can be characterized by a breakdown rate. Experiments with hard copper cavities showed that harder materials can reach larger accelerating …
High gradient studies for ILC with single-cell re-entrant shape and elliptical shape cavities made of fine-grain and large-grain niobium | IEEE Conference Publication | IEEE Xplore.
The present paper focuses on CABOTO (CArbon BOoster for Therapy in Oncology), a compact, efficient high-frequency linac that can accelerate C6+ ions and H2 molecules from 150–410 MeV/u in ∼24 ...
Previous high-power tests of X-band structure prototypes show that a gradient of 120 MV = m could be achieved for a 200 ns pulse length. Based on the law requiring that E 30 t 5 ¼ constant, this ...
RF breakdown studies. Experimental work on high gradient acceleration was a major part of early linear collider development, published by Balakin et al. [7] and by Loew et al. [8]. The work of Loew et al. [8] considered that the rf breakdowns were directly linked to peak electric field. They were studying the peak limit value of the electric ...
In this study, we investigated the effects of the high-gradient magnetic fields on the constituent supercooling and the grain refinement of alloys during the solidification process. The hypoeutectic Mn–89.7 wt% Sb alloy was chosen as a model alloy to carry out directional-solidification experiments in high-gradient magnetic fields.
Policy Scope of Policy. This Clinical Policy Bulletin addresses thermography. Experimental and Investigational. Aetna considers thermography (including digital infrared thermal imaging, magnetic resonance (MR) thermography and temperature gradient studies) experimental and investigational for all indications including the following (not an all …
This paper is a progress report on studies carried out at SLAC to assess the high-gradient behavior of 11.4 GHz copper accelerator structures for future linear colliders. the structures which have ...