2011 Particle Accelerator Conference - List of Authors (Li, R.K.)

Paper	Title	Page
MOP102	High-Gradient High-Energy-Gain Inverse Free Electron Laser Experiment using a Helical Undulator	289
	J.P. Duris, R.K. Li, P. Musumeci, E.W. Threlkeld, M.T. Westfall UCLA, Los Angeles, California, USA
	Funding: UC Lab fee award 09-LR-04-117055-MUSP DOE-HEP grant DE-FG02-92ER40693 Defense Threat Reduction Agency, Basic Research Award # HDTRA1-10-1-0073 Preparations for a high energy gain inverse free electron laser (IFEL) experiment using an undulator and Brookhaven National Lab’s (BNL) Accelerator Test Facility’s (ATF) terawatt CO2 laser are underway. 3D simulations suggest that the experiment will likely accelerate a 50 MeV beam to 117 MeV in 54 cm while maintaining a low energy spread. The helical undulator is currently under construction at UCLA’s Particle Beam Physics Laboratory.

MOP287	Femtosecond RF Timing in Low Charge Photoinjectors	654
	C.M. Scoby, R.K. Li, J.T. Moody, P. Musumeci UCLA, Los Angeles, California, USA
	Funding: Office of Naval Research Grant No. N000140711174 and US Department of Energy Grant No. DE-FG02-92ER40693. Photoelectron gun rf parameter mapping is explored as an extension to electro-optic sampling to monitor bunch vs. laser relative time-of-arrival. The method is evaluated for timestamping sub-picocoulomb femtosecond laser-pumped dynamics in graphite via electron diffraction where the required timing resolution is < 10 fs. AL Cavalieri, et al. Phys. Rev. Lett. 94, 114801 (2005) A Azima, et al. Appl. Phys. Lett. 94, 144102 (2009) CM Scoby, et al. PRST-AB 13, 022801 (2010) **KJ Kim, Rev. Nucl. Inst. Meth. A 275, 2 (1989)

WEP189	Compression and Synchronization of an Ultra-short Electron Beam Using a THz Undulator Interaction	1843
	J.T. Moody, R.K. Li, P. Musumeci, C.M. Scoby, H.L. To UCLA, Los Angeles, California, USA
	Funding: DOE-BES No. DE-FG02-92ER40693 and DOE-BES No. DE-FG02-07ER46272 Injection of electron beams into laser driven picosecond scale accelerating structures demand highly synchronized electron beams with bunch lengths approaching the femtosecond scale. One-dimensional numerical studies of undulator interactions of 3.5 MeV sub-picosecond electron beams and THz pulse trains produced by optical rectification have shown substantial compression and a reduction in time of arrival jitter with respect to the accelerator drive laser from the scale of hundreds of fs to that of tens of fs. In this paper a THz undulator based compression and synchronization scheme is investigated.

WEP289	The Impact of Laser Polarization in Multiphoton Photoemission from a Copper Cathode	2026
	R.K. Li, J.T. Moody, P. Musumeci, C.M. Scoby, H.L. To, M.T. Westfall UCLA, Los Angeles, California, USA
	Multiphoton photoemission from a copper cathode has been recently demonstrated to be a simple and efficient method to generate high quality electron beams. To further improve this scheme to achieve higher charge yielding efficiency and lower intrinsic emittance, we explored the effects of laser polarization at oblique incidence. Charge yields of s and p polarization from coated and uncoated cathodes were measured. The vectorial photoelectric effect was observed on the uncoated cathode but much less evident on the coated one, suggesting that surface properties are critical to the vectorial effect and in general important in photoemission. The results not only are useful in the optimization of an rf photoinjector, but also allow deeper understanding of the photoemission physics. * P. Musumeci et al., Phys. Rev. Lett. ZeHn4, 084801 (2010). ** P. Musumeci et al., Phys. Rev. Lett. ZeHn0, 244801 (2008).

Paper

Title

Page

High-Gradient High-Energy-Gain Inverse Free Electron Laser Experiment using a Helical Undulator

289

J.P. Duris, R.K. Li, P. Musumeci, E.W. Threlkeld, M.T. Westfall
UCLA, Los Angeles, California, USA

Funding: UC Lab fee award 09-LR-04-117055-MUSP DOE-HEP grant DE-FG02-92ER40693 Defense Threat Reduction Agency, Basic Research Award # HDTRA1-10-1-0073
Preparations for a high energy gain inverse free electron laser (IFEL) experiment using an undulator and Brookhaven National Lab’s (BNL) Accelerator Test Facility’s (ATF) terawatt CO2 laser are underway. 3D simulations suggest that the experiment will likely accelerate a 50 MeV beam to 117 MeV in 54 cm while maintaining a low energy spread. The helical undulator is currently under construction at UCLA’s Particle Beam Physics Laboratory.

MOP287

Femtosecond RF Timing in Low Charge Photoinjectors

654

C.M. Scoby, R.K. Li, J.T. Moody, P. Musumeci
UCLA, Los Angeles, California, USA

Funding: Office of Naval Research Grant No. N000140711174 and US Department of Energy Grant No. DE-FG02-92ER40693.
Photoelectron gun rf parameter mapping is explored as an extension to electro-optic sampling to monitor bunch vs. laser relative time-of-arrival. The method is evaluated for timestamping sub-picocoulomb femtosecond laser-pumped dynamics in graphite via electron diffraction where the required timing resolution is < 10 fs.
*AL Cavalieri, et al. Phys. Rev. Lett. 94, 114801 (2005)
**A Azima, et al. Appl. Phys. Lett. 94, 144102 (2009)
***CM Scoby, et al. PRST-AB 13, 022801 (2010)
****KJ Kim, Rev. Nucl. Inst. Meth. A 275, 2 (1989)

WEP189

Compression and Synchronization of an Ultra-short Electron Beam Using a THz Undulator Interaction

1843

J.T. Moody, R.K. Li, P. Musumeci, C.M. Scoby, H.L. To
UCLA, Los Angeles, California, USA

Funding: DOE-BES No. DE-FG02-92ER40693 and DOE-BES No. DE-FG02-07ER46272
Injection of electron beams into laser driven picosecond scale accelerating structures demand highly synchronized electron beams with bunch lengths approaching the femtosecond scale. One-dimensional numerical studies of undulator interactions of 3.5 MeV sub-picosecond electron beams and THz pulse trains produced by optical rectification have shown substantial compression and a reduction in time of arrival jitter with respect to the accelerator drive laser from the scale of hundreds of fs to that of tens of fs. In this paper a THz undulator based compression and synchronization scheme is investigated.

WEP289

The Impact of Laser Polarization in Multiphoton Photoemission from a Copper Cathode

2026

R.K. Li, J.T. Moody, P. Musumeci, C.M. Scoby, H.L. To, M.T. Westfall
UCLA, Los Angeles, California, USA

Multiphoton photoemission from a copper cathode has been recently demonstrated to be a simple and efficient method to generate high quality electron beams. To further improve this scheme to achieve higher charge yielding efficiency and lower intrinsic emittance, we explored the effects of laser polarization at oblique incidence. Charge yields of s and p polarization from coated and uncoated cathodes were measured. The vectorial photoelectric effect was observed on the uncoated cathode but much less evident on the coated one, suggesting that surface properties are critical to the vectorial effect and in general important in photoemission. The results not only are useful in the optimization of an rf photoinjector, but also allow deeper understanding of the photoemission physics.
* P. Musumeci et al., Phys. Rev. Lett. ZeHn4, 084801 (2010).
** P. Musumeci et al., Phys. Rev. Lett. ZeHn0, 244801 (2008).