6,044 research outputs found

    Research into the feasibility of thin metal and oxide film capacitors

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    Feasibility of thin metal and oxide film capacitor

    Sub-picosecond compression by velocity bunching in a photo-injector

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    We present an experimental evidence of a bunch compression scheme that uses a traveling wave accelerating structure as a compressor. The bunch length issued from a laser-driven radio-frequency electron source was compressed by a factor >3 using an S-band traveling wave structure located immediately downstream from the electron source. Experimental data are found to be in good agreement with particle tracking simulations.Comment: 19 pages, 9 figures, submitted to Phys. Rev. Spec. Topics A&

    Feeling Connected: Examining the Importance of Human Connection on the Personal Outlook of Social Service Providers Working with the Homeless During the COVID-19 Pandemic

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    Abstract This research study explores the lived experiences of social workers and social service providers (collectively referred to as ‘providers’) working with the homeless and homeless-adjacent populations in the early phases of the COVID-19 pandemic. We examine how the pandemic changed the work providers do, and how providers coped with and adapted to these changes. This research utilizes traditional qualitative interviews with a total of twenty providers located in the North-Western United States (NW-US). Key findings from this research indicate providers\u27 outcomes were influenced by the extent of their social connections to community, clients, and coworkers throughout the pandemic. This study confirms earlier research on the importance of social capital in minimizing negative mental health outcomes for providers working through situations that reflect large-scale social crises. This research has potential policy implications for provider networks in the event of similar crises in the future

    Millisecond accuracy video display using OpenGL under Linux

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    To measure people’s reaction times to the nearest millisecond, it is necessary to know exactly when a stimulus is displayed. This article describes how to display stimuli with millisecond accuracy on a normal CRT monitor, using a PC running Linux. A simple C program is presented to illustrate how this may be done within X Windows using the OpenGL rendering system. A test of this system is reported that demonstrates that stimuli may be consistently displayed with millisecond accuracy. An algorithm is presented that allows the exact time of stimulus presentation to be deduced, even if there are relatively large errors in measuring the display time

    The Peak Brightness and Spatial Distribution of AGB Stars Near the Nucleus of M32

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    The bright stellar content near the center of the Local Group elliptical galaxy M32 is investigated with 0.12 arcsec FWHM H and K images obtained with the Gemini Mauna Kea telescope. Stars with K = 15.5, which are likely evolving near the tip of the asymptotic giant branch (AGB), are resolved to within 2 arcsec of the nucleus, and it is concluded that the peak stellar brightness near the center of M32 is similar to that in the outer regions of the galaxy. Moreover, the projected density of bright AGB stars follows the visible light profile to within 2 arcsec of the nucleus, indicating that the brightest stars are well mixed throughout the galaxy. Thus, there is no evidence for an age gradient, and the radial variations in spectroscopic indices and ultraviolet colors that have been detected previously must be due to metallicity and/or some other parameter. We suggest that either the bright AGB stars formed as part of a highly uniform and coherent galaxy-wide episode of star formation, or they originated in a separate system that merged with M32.Comment: 9 pages of text, 3 figures. ApJ (Letters) in pres

    Excitation functions for (p,x) reactions of niobium in the energy range of Ep_{\text{p}} = 40-90 MeV

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    A stack of thin Nb foils was irradiated with the 100 MeV proton beam at Los Alamos National Laboratory's Isotope Production Facility, to investigate the 93^{93}Nb(p,4n)90^{90}Mo nuclear reaction as a monitor for intermediate energy proton experiments and to benchmark state-of-the-art reaction model codes. A set of 38 measured cross sections for nat^{\text{nat}}Nb(p,x) and nat^{\text{nat}}Cu(p,x) reactions between 40-90 MeV, as well as 5 independent measurements of isomer branching ratios, are reported. These are useful in medical and basic science radionuclide productions at intermediate energies. The nat^{\text{nat}}Cu(p,x)56^{56}Co, nat^{\text{nat}}Cu(p,x)62^{62}Zn, and nat^{\text{nat}}Cu(p,x)65^{65}Zn reactions were used to determine proton fluence, and all activities were quantified using HPGe spectrometry. Variance minimization techniques were employed to reduce systematic uncertainties in proton energy and fluence, improving the reliability of these measurements. The measured cross sections are shown to be in excellent agreement with literature values, and have been measured with improved precision compared with previous measurements. This work also reports the first measurement of the nat^{\text{nat}}Nb(p,x)82m^{82\text{m}}Rb reaction, and of the independent cross sections for nat^{\text{nat}}Cu(p,x)52g^{52\text{g}}Mn and nat^{\text{nat}}Nb(p,x)85g^{85\text{g}}Y in the 40-90 MeV region. The effects of nat^{\text{nat}}Si(p,x)22,24^{22,24}Na contamination, arising from silicone adhesive in the Kapton tape used to encapsulate the aluminum monitor foils, is also discussed as a cautionary note to future stacked-target cross section measurements. \emph{A priori} predictions of the reaction modeling codes CoH, EMPIRE, and TALYS are compared with experimentally measured values and used to explore the differences between codes for the nat^{\text{nat}}Nb(p,x) and nat^{\text{nat}}Cu(p,x) reactions.Comment: 34 pages, submitted to NIM-
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