Design, Construction, and Test of Compact, Distributed-Charge, X-Band Accelerator Systems that Enable Image-Guided, VHEE FLASH Radiotherapy.

The design and optimization of laser-Compton x-ray systems based on compact distributed charge accelerator structures can enable micron-scale imaging of disease and the concomitant production of beams of Very High Energy Electrons (VHEEs) capable of producing FLASH-relevant dose rates. The physics of laser-Compton x-ray scattering ensures that the scattered x-rays follow exactly the trajectory of the incident electrons, thus providing a route to image-guided, VHEE FLASH radiotherapy. The keys to a compact architecture capable of producing both laser-Compton x-rays and VHEEs are the use of X-band RF accelerator structures which have been demonstrated to operate with over 100 MeV/m acceleration gradients. The operation of these structures in a distributed charge mode in which each radiofrequency (RF) cycle of the drive RF pulse is filled with a low-charge, high-brightness electron bunch is enabled by the illumination of a high-brightness photogun with a train of UV laser pulses synchronized to the frequency of the underlying accelerator system. The UV pulse trains are created by a patented pulse synthesis approach which utilizes the RF clock of the accelerator to phase and amplitude modulate a narrow band continuous wave (CW) seed laser. In this way it is possible to produce up to 10 µA of average beam current from the accelerator. Such high current from a compact accelerator enables production of sufficient x-rays via laser-Compton scattering for clinical imaging and does so from a machine of "clinical" footprint. At the same time, the production of 1000 or greater individual micro-bunches per RF pulse enables > 10 nC of charge to be produced in a macrobunch of < 100 ns. The design, construction, and test of the 100-MeV class prototype system in Irvine, CA is also presented.

FEbeam: Cavity and electron emission data conversion, processing, and analysis. A freeware toolkit for rf injectors.

FEbeam is an all-in-one field emission data processing interface with the capability to analyze the field emission cathode performance in an rf injector by extracting the field enhancement factor, local field, and effective emission area from the Fowler-Nordheim equations. It also has the capability of processing beam imaging micrographs using its sister software, FEpic. The current version of FEbeam was designed for the Argonne Cathode Test-stand of the Argonne Wakefield Accelerator facility switch yard. With slight modifications, FEbeam could work for many rf field emission injectors. This software is open-source and can be found at GitHub.

Faculty perceptions of a professional development seminar.

A web-enhanced seminar was provided to address the pedagogical needs of professional faculty educators at a college of dentistry in a research-intensive university in fall 2006. In this qualitative report, the authors describe the participants' (n=12) perceptions and evaluation of the seminar. An evaluation of the seminar journals showed documented improvement in the participants' confidence and an enhanced awareness of their teaching practices. Six themes (new knowledge, planned change, awareness, changes made, current practice, and challenges to learning) ranging from 5.3 percent to 35.5 percent among four to twelve participants emerged across their learning journals. Participants also rated the course 4.9 on a five-point scale in helping them understand a variety of teaching modalities other than lecture and the sole use of multiple-choice tests as insufficient. When we invest resources in our faculty, progress is made towards ensuring quality teaching, as well as increased understanding and enhanced communication in the teaching and learning environment. This recursive process not only influences the faculty and those they teach but the patients they care for as well.

Promoting the teaching of critical thinking skills through faculty development.

Practical and effective faculty development programs are vital to individual and institutional success. However, there is little evidence that program outcomes result in instructional changes. The purpose of this study was to determine if and how faculty development would enhance participants' use of critical thinking skills in instruction. Seven faculty members from the University of Florida College of Dentistry and one faculty member from another health science college participated in six weekly two-hour faculty development sessions in spring 2007 that focused on enhancing critical thinking skills in instruction. Kaufman's and Rachal's principles of andragogy (adult learning) were used to design the sessions. Participants used learning journals to respond to four instructor-assigned prompts and provided one presentation to peers. With the use of qualitative methods, eight themes emerged across the learning journals: teaching goals, critical thinking, awareness of learners, planned instructional change, teaching efficacy, self-doubt, external challenges, and changes made. Five of eight participants incorporated critical thinking skills into their presentations at a mean level of 2.4 or higher on a 5-point scale using Paul and Elder's behavioral definition of critical thinking skills. Faculty development opportunities that cause participants to reason through learning journals, peer presentations, and group discussion demonstrated the incorporation of critical thinking concepts in 63 percent of this cohort group's presentations, suggesting that if evidence-based pedagogies are followed, instructional changes can result from faculty development.