Electrical charging during SIMS-analysis (secondary ion mass spectrometry) is a severe limitation for the analysis of non-conductive samples. In most cases this charging can be compensated with the aid of an electron gun. This is an already established method to analyze insulating samples. In this work results of a systematic study of electron gun charge compensation in our CAMECA ims5f ion mic...

For the operation of its mid-infrared FEL the superconducting electron accelerator S-DALINAC has to produce bunches with a charge of 6 pC and a duration of 2 ps FWHM. In order to achieve these figures a subharmonic injection scheme was added to the 3 GHz cw accelerator. The electron gun consists of a grid controlled thermionic cathode on a 250 kV terminal. It produces electron pulses with a cha...

The timing stability required for the SLC electron source is determined by the energy acceptance of the electron damping ring. The jitter requirements for the gun pulse itself are somewhat mitigated by the subsequent bunching process. The design of the system by which a gun pulse stability of u 20 ps is achieved is described, and experiments,to measure the resulting energy stability under vario...

Design and operation of a 50 MeV Electron Linear Accelerator utilizing a low emittance ( 7 c 5 to 10 mm-mrad) radio-frequency gun operating at an output energy of 5 MeV and a charge of 1 nC is described. Design calculations and early radio-frequency measurements and operational experience with the electron gun utilizing a dummy copper cathode in place of the proposed photocathode emitter are gi...

A prototype thermionic electron gun for a high-brightness X-ray generator has been developed. Its extraction voltage and design current are 60 kV and 100 mA (DC), respectively. The X-ray generator aims towards a maximum brilliance of 60 kW mm(-2). The beam sizes at the rotating anticathode must therefore be within 1.0 mm x 0.1 mm and a small beam emittance is required. The fabricated electron g...

The Linac Coherent Light Source (LCLS) will be the world’s first x-ray free electron laser, and the successful operation of this very shortwavelength FEL will require excellent beam quality from its electron source. Therefore a critical component is the RF photocathode injector. This paper describes the design issues of the LCLS RF gun and accelerator structures. The injector consists of a 1.6 ...

The design of the electron gun for an electron linear accelerator is of prime importance in achieving a small emittance volume and good reliability. This paper discusses phase space concepts useful in gun design, the design of the SLAC electron gun, and tests of its performance. A convenient definition for the effective area in phase space of a finite set of calculated points is proposed and a ...

During the past two decades instrumentation in scanning transmission electron microscopy (STEM) has pushed toward higher intensity electron probes to increase the signal-to-noise ratio of recorded images. While this is suitable for robust specimens, biological specimens require a much reduced electron dose for high-resolution imaging. We describe here protocols for low-dose STEM image recording...