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

Does Futures Price Volatility Differ Across Delivery Horizon?

We study the difference in the volatility dynamics of CBOT corn, soybeans, and oats futures prices across different delivery horizons via the smoothed Bayesian estimator of Karali, Dorfman, and Thurman (2010). We show that the futures price volatilities in these markets are affected by the inventories, time to delivery, and the crop progress period. Some of these effects vary across delivery horizons. Further, it is shown that the price volatility is higher before the harvest starts in most of the cases compared to the volatility during the planting period. These results have implications for hedging, options pricing, and the setting of margin requirements.Bayesian econometrics, futures markets, seasonality, theory of storage, volatility, Agribusiness, Agricultural and Food Policy, Agricultural Finance, Consumer/Household Economics, Demand and Price Analysis, Farm Management, Financial Economics, Marketing, Research Methods/ Statistical Methods, Risk and Uncertainty,

Do Inventory and Time-to-Delivery Effects Vary Across Futures Contracts? Insights from a Smoothed Bayesian Estimator

Replaced with revised version of paper 07/15/08.volatility, theory of storage, futures markets, Bayesian econometrics, lumber, Marketing,

A Survey of Projects Attempting to Provide Experimental Enrichment to Improve Improvement in Reading

In this complex modern world, reading is a medium of communication and a tool of learning that is an indispensable function in society (Tinker and McCullough, 1962) . For many years the issues of reading disability were argued in terms of genetic as compared to environmental factors . In the light of research it is now known that the home produces a powerful impact upon the child\u27s ability to learn and that social and cultural disadvantages can depress academic ability. Over the years educators have been aware of the importance that experience plays in the child\u27s preparation for reading. Hilliard and Troxell (1937) stated that the greater the child\u27s experience , the greater are his possibilities for success in reading and that children with a rich background are more strongly equipped to attack the printed page than are students who have a meager background. More than thirty years later we read: The more interesting and varied the experiences they share in, the more knowledge will expand and the larger their meaningful vocabulary will become. A young child grows in acquiring language through his daily contacts with interesting activities . . . Such growth is highly important to his later success in reading. (Gans , 1964, p. 41

READING THE BONES: A TAPHONOMIC INVESTIGATION OF ARCHAEOFAUNAL REMAINS RECOVERED FROM SITE 48PA551, NORTHWEST WYOMING

This is a preliminary taphonomy study of archaeofaunal remains found at site 48PA551, more commonly known as the Dead Indian Creek Site. 48PA551 is a well-known and commonly cited example of a McKean Complex occupation dating to between 3,800 and 4,800 B.P. The University of Montana held a field school at the site conducting small test excavations under the supervision of Dr. Anna Marie Prentiss in 2018. In the course of this testing a highly fragmentary bone bed consisting mostly of mammalian bone, cervids largely, was discovered eroding into the nearby creek. Ten 50 x 50 cm quadrants were excavated and a large number of faunal remains recovered. This study seeks to reconstruct taphonomic site history specifically focusing on what taphonomic agents and processes have created and impacted the data recovered from the Cut Bank. Using well established statistical methods, I test for both human and non-human processes that may have biasing effects on the data. In doing so patterns in the data emerge that build upon and reinforce interpretations from previous studies at this site. Implications for the importance of the contribution of this site to the greater understanding of the socio-economic changes that were taking place during the McKean complex are offered, as well as recommendations for future research and the need for further data recovery

An integrated eddy current detection and imaging system on a silicon chip

Eddy current probes have been used for many years for numerous sensing applications including crack detection in metals. However, these applications have traditionally used the eddy current effect in the form of a physically wound single or different probe pairs which of necessity must be made quite large compared to microelectronics dimensions. Also, the traditional wound probe can only take a point reading, although that point might include tens of individual cracks or crack arrays; thus, conventional eddy current probes are beset by two major problems: (1) no detailed information can be obtained about the crack or crack array; and (2) for applications such as quality assurance, a vast amount of time must be taken to scan a complete surface. Laboratory efforts have been made to fabricate linear arrays of single turn probes in a thick film format on a ceramic substrate as well as in a flexible cable format; however, such efforts inherently suffer from relatively large size requirements as well as sensitivity issues. Preliminary efforts to fully extend eddy current probing from a point or single dimensional level to a two dimensional micro-eddy current format on a silicon chip, which might overcome all of the above problems, are presented

Upgrades of beam diagnostics in support of emittance-exchange experiments at the Fermilab A0 photoinjector

The possibility of using electron beam phase space manipulations to support a free-electron laser accelerator design optimization has motivated our research. An on-going program demonstrating the exchange of transverse horizontal and longitudinal emittances at the Fermilab A0 photoinjector has benefited recently from the upgrade of several of the key diagnostics stations. Accurate measurements of these properties upstream and downstream of the exchanger beamline are needed. Improvements in the screen resolution term and reduced impact of the optical system's depth-of-focus by using YAG:Ce single crystals normal to the beam direction will be described. The requirement to measure small energy spreads (<10 keV) in the spectrometer and the exchange process which resulted in bunch lengths less than 500 fs led to other diagnostics performance adjustments and upgrades as well. A longitudinal to transverse exchange example is also reported.Comment: 16 p

Growth Of Ultrafine Particles By Brownian Coagulation

Current atmospheric observations tend to support the view that continental tropospheric aerosols (particularly urban aerosols) show multimodal mass distributions in the size range of 0.01-100 μm. The origin of these aerosols is both natural and anthropogenic. Recently, trimodal sub-μm size distributions from combustion measurements at 0.008, 0.035 and 0.15 μm were also observed. Our interest in the present study is the secondary process of growth of sub-μm size aerosols by the coagulation process alone. Using the \u27J-space\u27 (integer-space) distribution method of Salk (Suck) and Brock (1979, J. Aerosol Sci. 10, 58-590), we report an accurate numerical simulation study of the evolution of ultrafine to fine particle size distributions. Comparision with the analytic solution of Scott (1968, J. atmos. Sci. 25, 54-64) was made to test the accuracy of our J-space or integer-space distribution method. Our multimodal sub-μ particle size distribution study encompassed the particle size range of 0.001-0.20 μm. Details of particle growth in each mode and interaction between different modes in the multimodal distribution were qualitatively analyzed. © 1986