Synchroscan streak camera imaging at a 15-MeV photoinjector with emittance exchange

At the Fermilab A0 photoinjector facility, bunch-length measurements of the laser micropulse and the e-beam micropulse have been done in the past with a fast single-sweep module of the Hamamatsu C5680 streak camera with an intrinsic shot-to-shot trigger jitter of 10-20ps. We have upgraded the camera system with the synchroscan module tuned to 81.25MHz to provide synchronous summing capability with less than 1.5ps FWHM trigger jitter and a phase-locked delay box to provide phase stability of ~1ps over 10s of minutes. These steps allowed us to measure both the UV laser pulse train at 263nm and the e-beam via optical transition radiation (OTR). Due to the low electron beam energies and OTR signals, we typically summed over 50 micropulses with 0.25-1nC per micropulse. The phase-locked delay box allowed us to assess chromatic temporal effects and instigated another upgrade to an all-mirror input optics barrel. In addition, we added a slow sweep horizontal deflection plug-in unit to provide dual-sweep capability for the streak camera. We report on a series of measurements made during the commissioning of these upgrades including bunch-length and phase effects using the emittance exchange beamline and simultaneous imaging of a UV drive laser component, OTR, and the 800nm diagnostics laser.Comment: 26 p

Girls in Trouble : A History of Female Adolescent Sexuality in the Midwest, 1946-1964

This dissertation attempts to show how Americans reacted to adolescent female sexuality, looking specifically at unwed school-age pregnancy in the post-World War Two decades. It documents the origins of the transition of the conversation about unwed teens from caring for them in maternity homes and boarding houses to discussing their problems on television shows and in popular magazines. Teenage sexual delinquency and pregnancy have always raised innumerable questions about American culture and values. Because they challenged the traditional concept of motherhood, they offer a lens through which to study American sexuality and reveal that an alternate 1950s existed beyond the traditional stereotypes. Not all girls tacitly accepted the future set out for them. Teenagers actively made decisions regarding their bodies and sexuality. How girls behaved in response to the expectations placed upon them and how the public responded to female adolescents in the past reveals much about American youth, families, and society in general. Despite the fact that historians have devoted significant attention to this time period, few works focus solely on teenagers. The sexuality of female teenagers is often overlooked or combined with studies of women or college co-eds. This dissertation attempts to fill a gap in that literature and prove that the 1950s were indeed a crucial time for adolescents and sex in the United States. Girls `in Trouble\u27: A History of Female Adolescent Sexuality in the Midwest, 1946-1964 provides a complex picture of teenage sexuality and pregnancy in the postwar decades. It uses magazines and newspapers, specifically advice columns, to gain insight into public opinion of unwed mothers and teenage females. Letters from girls who wrote to these magazines and newspapers asking for guidance provide a glimpse into their thoughts and fears. Studies conducted by national and local agencies reveal how society addressed the growing problem of unwed pregnancy. Records from maternity homes in Chicago and Milwaukee provide information on the daily experiences of pregnant teens

Single-shot electro-optic sampling of coherent transition radiation at the A0 Photoinjector

Future collider applications and present high-gradient laser plasma wakefield accelerators operating with picosecond bunch durations place a higher demand on the time resolution of bunch distribution diagnostics. This demand has led to significant advancements in the field of electro-optic sampling over the past ten years. These methods allow the probing of diagnostic light such as coherent transition radiation or the bunch wakefields with sub-picosecond time resolution. Potential applications in shot-to-shot, non-interceptive diagnostics continue to be pursued for live beam monitoring of collider and pump-probe experiments. Related to our developing work with electro-optic imaging, we present results on single-shot electro-optic sampling of the coherent transition radiation from bunches generated at the A0 photoinjector.Comment: 3 p

A Marketing Plan for a Mature Dental Practice

The market faced by a dental practitioner today is radically different from the one twenty years ago. Thus, the mature dental practice must adapt and change in response. The cultural, social and legal issues which have created today\u27s dental marketplace are examined through a review of the literature. By means of an internal audit of the staff and a survey of current patients, attitudes toward one dental practice were acquired. Results of those surveys are explored for predictability. Demographic data was also gathered from the surveys, and the market currently served is identified. Additional target markets are identified and appropriate marketing concepts defined. Finally, based on research results, literature review and corporate mission, a marketing plan for this particular dental practice was developed

Peer leadership as an emerging high-impact practice: An exploratory study of the American experience

Given the powerful and ubiquitous qualities of peer influence, higher educators have begun to harness this resource in student support and service delivery by using undergraduates as leaders, mentors and educators for their fellow students. This paper analyses data from 1 942 students from 142 institutions in the United States who responded to a national survey of peer leaders administered by the National Resource Center for The First-Year Experience and Students in Transition in 2009. Descriptive and inferential analyses indicate that survey respondents often hold more than one peer leader position, academic positions were the most common peer leadership experiences, and they receive extensive training for their peer leader roles in the form of initial training, ongoing support and supervision by professional staff. Further, the overwhelming majority of survey respondents felt that their peer leadership experience was highly beneficial to their skill development, nature of interactions and campus integration. Students engaged in community service peer-leader roles reported positive change on more outcomes than peer-leader roles in academics, residence halls and orientation and peer leaders who received financial compensation reported positive differences on a wider range of self-rated outcomes than those students not receiving remuneration. In sum, the examination of peer-leader structures and outcomes provide suggestive evidence that peer leadership meets many of the criteria to be considered as a high-impact practice

Conversion of a transverse density modulation into a longitudinal phase space modulation using an emittance exchange technique

We report on an experiment to produce a train of sub-picosecond microbunches using a transverse-to-longitudinal emittance exchange technique. The generation of a modulation on the longitudinal phase space is done by converting an initial horizontal modulation produced using a multislits mask. The preliminary experimental data clearly demonstrate the conversion process. To date only the final energy modulation has been measured. However numerical simulations, in qualitative agreement with the measurements, indicate that the conversion process should also introduce a temporal modulation.Comment: 4 pages, 6 figures. Submitted to the proceedings of the Physics and Applications of High-Brightness Electron Beams (HBEB09), Nov. 16-19, 2009, Maui H