| Paper | Title | Page |
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| TUPML061 | Study of Mean Transverse Energy of (N)UNCD with Tunable Laser Source | 1677 |
| SUSPF050 | use link to see paper's listing under its alternate paper code | |
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Funding: NSF grant No. NSF-1739150, DOE SBIR program grant No. DE-SC0013145, NSF grant No. PHYS-1535279, DOE Contract No. DE-AC02-06CH11357. There is a strong motivation to develop and understand novel materials with the potential to be utilized as photocathodes, as these could have desirable photoemission properties for research and industrial applications. Nitrogen-incorporated ultrananocrystalline diamond ((N)UNCD) photocathodes have potential to become a material of choice for photocathode applications*. (N)UNCD has high quantum efficiency when processed in hydrogen plasma*, low surface roughness, and high electron conductivity through the bulk**. The mean transverse energy (MTE) was calculated for (N)UNCD thin films using the double-solenoid scan method. (N)UNCD thin film with thickness of 160nm was deposited on highly-doped silicon substrate. Studies of the MTE of a (N)UNCD sample were done using a tunable laser source with photon energies of 3.56 eV to 5.26 eV. These results are presented. * K.J. Pérez Quintero et al., Appl. Phys. Lett. 105, 123103 (2014). ** S. Bhattacharyya et al., Appl. Phys. Lett. 79, 1441 (2001) |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML061 | |
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| TUPML064 | Staged Two Beam Acceleration Beam Line Design for the AWA Facility | 1688 |
| SUSPF040 | use link to see paper's listing under its alternate paper code | |
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Funding: This work is funded by the DOE Office of Science, grant no. DE-SC0015479, and contract No. DE-AC02- 06CH11357. Two beam acceleration is a candidate for future high energy physics machines and FEL user facilities. This scheme consists of two independent electron beam lines operating synchronously. High-charge, 70 MeV drive bunch trains are injected from the RF photo-injector into decelerating structures to generate a few hundred of MW of RF power. This RF power is transferred through an RF waveguide to accelerating structures that are used to accelerate the witness beam. Staging refers to the sequential acceleration (energy gain) in two or more structures on the witness beam line. A kicker was incorporated on the drive beam line to accomplish a modular design so that each accelerating structure can be independently powered by a separate drive beam. Simulations were performed in OPAL-T to model the two beam lines. Beam sizes at the center of the structures was minimized to ensure good charge transmission. The resulting design will be the basis for proof of principle experiments that will take place at the Argonne Wakefield Accelerator (AWA) facility. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML064 | |
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| THPMF048 | Bunch Length Measurements Using CTR at the AWA with Comparison to Simulation | 4166 |
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Funding: This work is funded by the DOE Office of Science, grant no. DE-SC0015479, and contract No. DE-AC02- 06CH11357. In this paper we present electron bunch length measurements at the Argonne Wakefield Accelerator (AWA) photoinjector facility. The AWA accelerator has a large dynamic charge density range, with electron beam charge varying between 0.1 nC - 100 nC, and laser spot size diameter at the cathode between 0.1 mm - 18 mm. The bunch length measurements were taken at different charge densities using a metallic screen and a Martin-Puplett interferometer to perform autocorrelation scans of the corresponding coherent transition radiation (CTR). A liquid helium-cooled 4K bolometer was used to register the interferometer signal. The experimental results are compared with Impact-T and OPAL-T numerical simulations. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF048 | |
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| THPMF049 | Photoinjector Optimization Studies at the AWA | 4169 |
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Funding: This work is funded by the DOE Office of Science, grant no. DE-SC0015479, and contract No. DE-AC02- 06CH11357. With a variable charge range of 0.1 nC - 100 nC, the Argonne Wakefield Accelerator facility (AWA) has a unique and dynamic set of operating parameters. Adjustment of the optics and occasionally the rf phases is required each time the bunch charge is changed. Presently, these adjustments are done by the operator during each experiment. This is time consuming and inefficient, more so at high charge and for complex experimental set ups. In an attempt to reduce the amount of time spent adjusting parameters by hand, several optimization methods in simulation are being explored. This includes using the well-known Genetic Algorithm (NSGA-II), incorporated into OPAL-T. We have also investigated a model-based method and novel structure based algorithms developed at ANL. Ongoing efforts include using these optimization methods to improve operations at the AWA. Simulation results will be compared to measured beam parameters at the AWA, and one optimization method will be selected for use in guiding operations going forward. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF049 | |
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