Nonlinear electrostatic emittance compensation in kA, fs electron bunches

Nonlinear space-charge effects play an important role in emittance growth in the production of kA electron bunches with a bunch length much smaller than the bunch diameter. We propose a scheme employing the radial third-order component of an electrostatic acceleration field, to fully compensate the nonlinear space-charge effects. This results in minimal transverse root-mean-square emittance. The principle is demonstrated using our design simulations of a device for the production of high-quality, high-current, subpicosecond electron bunches using electrostatic acceleration in a 1 GV/m field. Simulations using the GPT code produce a bunch of 100 pC and 73 fs full width at half maximum pulse width, resulting in a peak current of about 1.2 kA at an energy of 2 MeV. The compensation scheme reduces the root-mean-square emittance by 34% to 0.4p mm mrad

Compression of sub-relativistic space-charge-dominated electron bunches for singleshot femtosecond electron diffraction

We demonstrate the compression of 95 keV, space-charge-dominated electron bunches to sub-100 fs durations. These bunches have sufficient charge (200 fC) and are of sufficient quality to capture a diffraction pattern with a single shot, which we demonstrate by a diffraction experiment on a polycrystalline gold foil. Compression is realized by means of velocity bunching by inverting the positive space-charge-induced velocity chirp. This inversion is induced by the oscillatory longitudinal electric field of a 3 GHz radio-frequency cavity. The arrival time jitter is measured to be 80 fs

Central Florida Future, Vol. 23 No. 16, October 11, 1990

Engineering official dies of heart attack 62-year-old had chest pains, felt faint; \u27UCF\u27 will replace existing campus phone exchanges; Truck strikes, injures student riding bike near entrance to UCF;https://stars.library.ucf.edu/centralfloridafuture/2021/thumbnail.jp

Long-term morphological changes of symptomatic lacunar infarcts and surrounding white matter on structural MRI

The contributing studies were funded by the Chief Scientist Office of the Scottish Executive (grant 217 NTU R37933), the Wellcome Trust (grants 075611 and WT088134/Z/09/A), and Row Fogo Charitable Trust. The imaging was performed at the Brain Research Imaging Centre Edinburgh, which is supported by the SINAPSE (Scottish Imaging Network, A Platform for Scientific Excellence) collaboration and the Chief Scientist Office of the Scottish Government (http://www.bric.ed.ac.uk/). This work was supported by European Union Horizon 2020 (EU H2020), PHC- 03 to 15, project No. 666881, SVDs@Target, and the Fondation Leducq Transatlantic Network of Excellence for Study of Perivascular Spaces in Small Vessel Disease, ref No. 16 CVD 05. Dr Loos was supported by the Dutch Alzheimer Foundation.Peer reviewedPublisher PD

Ultracold Electron Source

Abstract only

Ultracold Electron Source

Abstract only

Construction of the alpha-X photo-injector cavity

JACoW web site http://accelconf.web.cern.ch/Accelconf/e06/We will describe the construction and low power testing of an RF cavity to be used as a photo-injector for the ALPHA-X project within the Department of Physics at the University of Strathclyde (UK). The gun is a two and a half cell S-band cavity, employing a metallic photocathode. RF power is coupled to the gun via a co-axial power coupler. The specification of the gun and the low power measurements made to achieve the correct mode frequency and field flatness will be presented