110 research outputs found
Measurements of sub-nT dynamic magnetic field shielding with soft iron and mu-metal for use in linear colliders
There is an increasing need to shield beams and accelerator elements from
stray magnetic fields. The application of magnetic shielding in linear
colliders is discussed. The shielding performance of soft iron and mu-metal is
measured for magnetic fields of varying amplitude and frequency. Special
attention is given to characterise the shielding performance for very
small-amplitude magnetic fields
Measurements and modelling of stray magnetic fields and the simulation of their impact on the Compact Linear Collider at 380 GeV
The Compact Linear Collider (CLIC) targets a nanometre beam size at the
collision point. Realising this beam size requires the generation and transport
of ultra-low emittance beams. Dynamic imperfections can deflect the colliding
beams, leading to a collision with a relative offset. They can also degrade the
emittance of each beam. Both of these effects can significantly impact the
luminosity of CLIC. In this paper, we examine a newly considered dynamic
imperfection: stray magnetic fields. Measurements of stray magnetic fields in
the Large Hadron Collider tunnel are presented and used to develop a
statistical model that can be used to realistically generate stray magnetic
fields in simulations. The model is used in integrated simulations of CLIC at
380GeV including mitigation systems for stray magnetic fields to evaluate their
impact on luminosity
Design and operation of a prototype interaction point beam collision feedback system for the International Linear Collider
A high-resolution, intratrain position feedback system has been developed to
achieve and maintain collisions at the proposed future electron-positron
International Linear Collider (ILC). A prototype has been commissioned and
tested with a beam in the extraction line of the Accelerator Test Facility at
the High Energy Accelerator Research Organization in Japan. It consists of a
stripline beam position monitor (BPM) with analogue signal-processing
electronics, a custom digital board to perform the feedback calculation, and a
stripline kicker driven by a high-current amplifier. The closed-loop feedback
latency is 148 ns. For a three-bunch train with 154 ns bunch spacing, the
feedback system has been used to stabilize the third bunch to 450 nm. The
kicker response is linear, and the feedback performance is maintained, over a
correction range of over 60 {\mu}m. The propagation of the correction has
been confirmed by using an independent stripline BPM located downstream of the
feedback system. The system has been demonstrated to meet the BPM resolution,
beam kick, and latency requirements for the ILC
CT Characteristics of Pheochromocytoma: Relevance for the Evaluation of Adrenal Incidentaloma.
BACKGROUND: Up to 7% of all adrenal incidentalomas (AIs) are pheochromocytomas (PCCs). In the evaluation of AI, it is generally recommended that PCC be excluded by measurement of plasma-free or 24-hour urinary fractionated metanephrines. However, recent studies suggest that biochemical exclusion of PCC not be performed for lesions with CT characteristics of an adrenocortical adenoma (ACA). AIM: To determine the proportion of PCCs with ACA-like attenuation or contrast washout on CT. METHODS: For this multicenter retrospective study, two central investigators independently analyzed the CT reports of 533 patients with 548 histologically confirmed PCCs. Data on tumor size, unenhanced Hounsfield units (HU), absolute percentage washout (APW), and relative percentage washout (RPW) were collected in addition to clinical parameters. RESULTS: Among the 376 PCCs for which unenhanced attenuation data were available, 374 had an attenuation of >10 HU (99.5%). In the two exceptions (0.5%), unenhanced attenuation was exactly 10 HU, which lies just within the range of ≤10 HU that would suggest a diagnosis of ACA. Of 76 PCCs with unenhanced HU > 10 and available washout data, 22 (28.9%) had a high APW and/or RPW, suggestive of ACA. CONCLUSION: Based on the lack of PCCs with an unenhanced attenuation of <10 HU and the low proportion (0.5%) of PCCs with an attenuation of 10 HU, it seems reasonable to abstain from biochemical testing for PCC in AIs with an unenhanced attenuation of ≤10 HU. The assessment of contrast washout, however, is unreliable for ruling out PCC
The ESSnuSB design study: overview and future prospects
ESSnuSB is a design study for an experiment to measure the CP violation in
the leptonic sector at the second neutrino oscillation maximum using a neutrino
beam driven by the uniquely powerful ESS linear accelerator. The reduced impact
of systematic errors on sensitivity at the second maximum allows for a very
precise measurement of the CP violating parameter. This review describes the
fundamental advantages of measurement at the 2nd maximum, the necessary
upgrades to the ESS linac in order to produce a neutrino beam, the near and far
detector complexes, the expected physics reach of the proposed ESSnuSB
experiment, concluding with the near future developments aimed at the project
realization.Comment: 19 pages, 11 figures; Corrected minor error in alphabetical ordering
of the authors: the author list is now fully alphabetical w.r.t. author
surnames as was intended. Corrected an incorrect affiliation for two authors
per their reques
An analysis-ready and quality controlled resource for pediatric brain white-matter research
We created a set of resources to enable research based on openly-available diffusion MRI (dMRI) data from the Healthy Brain Network (HBN) study. First, we curated the HBN dMRI data (N = 2747) into the Brain Imaging Data Structure and preprocessed it according to best-practices, including denoising and correcting for motion effects, susceptibility-related distortions, and eddy currents. Preprocessed, analysis-ready data was made openly available. Data quality plays a key role in the analysis of dMRI. To optimize QC and scale it to this large dataset, we trained a neural network through the combination of a small data subset scored by experts and a larger set scored by community scientists. The network performs QC highly concordant with that of experts on a held out set (ROC-AUC = 0.947). A further analysis of the neural network demonstrates that it relies on image features with relevance to QC. Altogether, this work both delivers resources to advance transdiagnostic research in brain connectivity and pediatric mental health, and establishes a novel paradigm for automated QC of large datasets
International multicenter survey on screening and confirmatory testing in primary aldosteronism
Objective: Primary aldosteronism (PA) is one of the most frequent causes of secondary hypertension. Although clinical practice guidelines recommend a diagnostic process, details of the steps remain incompletely standardized. Design: In the present SCOT-PA survey, we have investigated the diversity of approaches utilized for each diagnostic step in different expert centers through a survey using Google questionnaires. A total of 33 centers from 3 continents participated. Results: We demonstrated a prominent diversity in the conditions of blood sampling, assay methods for aldosterone and renin, and the methods and diagnostic cutoff for screening and confirmatory tests. The most standard measures were modification of antihypertensive medication and sitting posture for blood sampling, measurement of plasma aldosterone concentration (PAC) and active renin concentration by chemiluminescence enzyme immunoassay, a combination of aldosterone-to-renin ratio with PAC as an index for screening, and saline infusion test in a seated position for confirmatory testing. The cutoff values for screening and confirmatory testing showed significant variation among centers. Conclusions: Diversity of the diagnostic steps may lead to an inconsistent diagnosis of PA among centers and limit comparison of evidence for PA between different centers. We expect the impact of this diversity to be most prominent in patients with mild PA. The survey raises 2 issues: the need for standardization of the diagnostic process and revisiting the concept of mild PA. Further standardization of the diagnostic process/criteria will improve the quality of evidence and management of patients with PA.Metabolic health: pathophysiological trajectories and therap
'Omic approaches to preventing or managing metastatic breast cancer
Early detection of metastasis-prone breast cancers and characterization of residual metastatic cancers are important in efforts to improve management of breast cancer. Applications of genome-scale molecular analysis technologies are making these complementary approaches possible by revealing molecular features uniquely associated with metastatic disease. Assays that reveal these molecular features will facilitate development of anatomic, histological and blood-based strategies that may enable detection prior to metastatic spread. Knowledge of these features also will guide development of therapeutic strategies that can be applied when metastatic disease burden is low, thereby increasing the probability of a curative response
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