566 research outputs found
Formation and Acceleration of Uniformly-Filled Ellipsoidal Electron Bunches Obtained via Space-Charge-Driven Expansion from a Cesium-Telluride Photocathode
We report the experimental generation, acceleration and characterization of a
uniformly-filled electron bunch obtained via space-charge-driven expansion
(often referred to as "blow-out regime") in an L-band (1.3-GHz) radiofrequency
photoinjector. The beam is photoemitted from a Cesium-Telluride semiconductor
photocathode using a short ( fs) ultraviolet laser pulse. The produced
electron bunches are characterized with conventional diagnostics and the
signatures of their ellipsoidal character is observed. We especially
demonstrate the production of ellipsoidal bunches with charges up to
nC corresponding to a -fold increase compared to previous experiments
with metallic photocathodes.Comment: 9, pages, 13 figure
Amp\`ere-Class Pulsed Field Emission from Carbon-Nanotube Cathodes in a Radiofrequency Resonator
Pulsed field emission from cold carbon-nanotube cathodes placed in a
radiofrequency resonant cavity was observed. The cathodes were located on the
backplate of a conventional -cell resonant cavity operating at
1.3-GHz and resulted in the production of bunch train with maximum average
current close to 0.7 Amp\`ere. The measured Fowler-Nordheim characteristic,
transverse emittance, and pulse duration are presented and, when possible,
compared to numerical simulations. The implications of our results to
high-average-current electron sources are briefly discussed.Comment: 5 pages, 6 figures; submitted to Applied Physics Letter
Design of a high-power compact SRF linac for industrial applications of e-beam irradiation
Fermilab has developed a novel concept for an industrial electron linac using
Nb3Sn coating technology and conduction cooling. These conduction-cooled linacs
can generate electron beam energies up to 10 MeV in continuous-wave operation
and reach higher power (>=1 MW) by combing several modules. Compact and light
enough to mount on mobile platforms, our machine is anticipated to enable new
in-situ environmental remediation applications such as waste-water treatment
for urban areas, X-ray medical device sterilization, and innovative pavement
applications. We highlight a few aspects of a 1 MW design of such a machine in
this paper. A detailed plan is in Dhuley et al. (2022) Phys. Rev. Accel. Beams
25, 041601.Comment: arXiv admin note: substantial text overlap with arXiv:2112.0923
Experimental study of coherent synchrotron radiation in the emittance exchange line at the A0-photoinjector
Next generation accelerators will require a high current, low emittance beam
with a low energy spread. Such accelerators will employ advanced beam
conditioning systems such as emittance exchangers to manipulate high brightness
beams. One of the goals of the Fermilab A0 photoinjector is to investigate the
transverse to longitudinal emittance exchange principle. Coherent synchrotron
radiation could limit high current operation of the emittance exchanger. In
this paper, we report on the preliminary experimental and simulation study of
the coherent synchroton radiation (CSR) in the emittance exchange line at the
A0 photoinjector.Comment: 4 pp. 14th Advanced Accelerator Concepts Workshop, 13-19 Jun 2010:
Annapolis, Marylan
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ROMOP: a light-weight R package for interfacing with OMOP-formatted electronic health record data.
Objectives:Electronic health record (EHR) data are increasingly used for biomedical discoveries. The nature of the data, however, requires expertise in both data science and EHR structure. The Observational Medical Out-comes Partnership (OMOP) common data model (CDM) standardizes the language and structure of EHR data to promote interoperability of EHR data for research. While the OMOP CDM is valuable and more attuned to research purposes, it still requires extensive domain knowledge to utilize effectively, potentially limiting more widespread adoption of EHR data for research and quality improvement. Materials and methods:We have created ROMOP: an R package for direct interfacing with EHR data in the OMOP CDM format. Results:ROMOP streamlines typical EHR-related data processes. Its functions include exploration of data types, extraction and summarization of patient clinical and demographic data, and patient searches using any CDM vocabulary concept. Conclusion:ROMOP is freely available under the Massachusetts Institute of Technology (MIT) license and can be obtained from GitHub (http://github.com/BenGlicksberg/ROMOP). We detail instructions for setup and use in the Supplementary Materials. Additionally, we provide a public sandbox server containing synthesized clinical data for users to explore OMOP data and ROMOP (http://romop.ucsf.edu)
No association of androgen receptor GGN repeat length polymorphism with infertility in Indian men
Androgens, acting through the androgen receptor (AR), play a role in secondary sexual differentiation from the prenatal stage to adulthood, including spermatogenesis. The AR gene has 2 polymorphic trinucleotide repeats (CAG and GGN) in exon 1. The CAG repeat length polymorphism has been well studied in a variety of medical conditions, including male infertility. Many of these studies have shown an association of the expanded CAG repeats with male infertility, although this is not true for all populations. The GGN repeat, in contrast, has been less thoroughly studied. Thus far, only 4 reports worldwide have analyzed the GGN repeat, alone or in combination with the CAG repeat, in male infertility cases. No such study has been undertaken on infertile Indian men. Therefore, we have analyzed AR-GGN repeats in a total of 595 Indian males, including 277 azoospemric, 97 oligozoospermic, and 21 oligoteratozoospermic cases, along with 200 normozoospermic controls. The analysis revealed no difference in the mean number or the range of the repeat between cases (mean=21.51 repeats, range 15-26 repeats) and controls (mean 21.58 repeats, range 15-26 repeats). Furthermore, no difference was observed when azoospermic (mean=21.53 repeats, range 15-26 repeats), oligozoospermic (mean=21.46 repeats, range 15-26 repeats), and oligoteratozoospermic cases (mean=21.48, range 19-26 repeats) were compared individually with the controls
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