MOPCTH008
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
We present the results of transverse emittance and longitudinal current profile measurements of high bunch charge (>100 pC) beams produced in the dc gun-based Cornell photoinjector. In particular, we show that the cathode thermal emittance dominates the final emittance at charges up to 300 pC. Additionally, we demonstrate excellent agreement between optimized 3D space charge simulations and measurement, and show that the quality of the transverse laser distribution limits the optimal simulated and measured emittances.
TUPATH019
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
HZB, Berlin, Germany
TUICLH1024
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
The initial transverse distribution of a space charge dominated electron beam from low energy sources (100s of kV) can have a significant impact on the downstream emittance evolution. Using a liquid crystal spatial light modulator and visible light, the transverse laser distribution can be shaped to high accuracy with good efficiency. Using this shaped transverse distribution, adaptively shaped electron beams of high accuracy from a high voltage DC photoemission gun are presented.
THIALH2070
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
We have developed a cost-effective, fast rotating wire scanner for use in accelerators where high beam currents would otherwise melt even carbon wires. This new design uses a simple planetary gear setup to rotate a tungsten or carbon wire, fixed at one end, through the beam at speeds in excess of 20 m/s. We present results from bench tests, as well as transverse beam profile measurements taken at Cornell’s high-brightness ERL photoinjector, for beam currents up to 35 mA.
THIALH2071
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
We evaluate the effectiveness of three ion-clearing strategies in the Cornell high intensity photoinjector: DC clearing electrodes, bunch gaps, and beam shaking. We present data from recent experiments where we directly measured the residual trapped ion density while employing these clearing methods. Several theoretical models have been developed to estimate the ion creation and clearing rates. The data is well explained by two independent simulation codes that track the motion of ions trapped in the electric field generated by the beam.
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
HZB, Berlin, Germany