Engineering Commons^™

A Prototype Microwave Cavity Control Circuit For Use In Next Generation Free Electron Laser, Josh Thompson, Peter Neal Barrina, Jiayi Jiang, Joe Frisch, Steve Smith, Daniel Van Winkle

STAR Program Research Presentations

One of the current programs at SLAC National Accelerator Laboratory is the Linac Coherent Light Source, or LCLS. Using the existing hardware of the last third of their linear accelerator (or “linac”), SLAC has created one of the most energetic X-ray free electron lasers (or “FEL”). Since 2009, LCLS has used this FEL to perform a wide range of experiments across all sciences, most notably ultrafast filming at the molecular scale. As requests for beam-time with this laser increases, SLAC is purposing a linac upgrade to better match this demand. This upgrade, named LCLS-II, will replace existing copper radio frequency …

Does A Plastron Improve Heat Transfer?, Madani A. Khan, Jeffrey Alston, Andrew Guenthner

STAR Program Research Presentations

Superamphiphobic surfaces strongly repel both water and oils. In this work, aluminum coupons are processed by sanding with various grit of sand paper to impart microscale roughness. Subsequent submersion of the aluminum substrate in boiling water grows nanoscale grass-like structures. The oxide layer of Al is slightly soluble in water. During a fast diffusion/equilibrium, Al₂O₃ nanograss grows on the surface. A low energy coating is then deposited on the surface. The micro and nanoscale features create re-entrant structures that trap air enabling contact liquid to be in a Cassie-Baxter state. Superamphiphobicity of the samples were confirmed by …

Evolution Of Perturbations In Flow Field Mechanics, Samantha R. Bell, David Forliti, Nils Sedano, Kriss Vanderhyde

STAR Program Research Presentations

This project explores the stability analysis of a given flow field. Specifically, where the peak disturbance occurs in a flow as this is the disturbance that is most likely to occur. In rocket combustion, it is important to understand where the maximum disturbance occurs so that the mixing of fuel can be stabilized. The instabilities are the results of frequencies in the area surrounding the flow field. The linear stability governing equations are employed to better understand the disturbance. The governing equations for continuity and momentum in the x and y directions are used to form an equation for the …

Feedback Stabilization At Spear3, Daniel Kelley, Jeff Corbett

STAR Program Research Presentations

The SPEAR3 synchrotron lightsource at SLAC relies on a sophisticated radio frequency (RF) timing system to maintain current – electrons – in the storage ring. One problem SPEAR3 operators have dealt with is the thermal expansion of one of the cables supporting this RF timing system. As the cable expands and contracts with the diurnal rise and fall of the sun, the phase of the RF in the cable shifts. This shifting phase affects the timing accuracy of electron injections into the storage ring.

A common feedback control algorithm PID (Proportional Integral Derivative) has countless applications in engineering. PID feedback …

Assessing Laser Lifetime Test Performance, Joe Weichman, Hamid Hemmati, Malcolm Wright

STAR Program Research Presentations

Assessing expected component lifetime is necessary in developing instruments for future space-flight projects to ensure long term operation in the challenging environment. Although semiconductor diode lasers have widespread use in terrestrial applications, their use in space is still an emerging technology that requires on-going testing to demonstrate their capability. The project called for re-establishing the test setup for assessing lifetime performance of 20 continuously running 200mW 830 nm diode lasers. These lasers underwent previous testing based on parameters for NuSTAR’s laser metrology system, and met the six month lifetime project requirements under nominal operating conditions. Laser testing is currently underway …