Barrier RF Stacking

A novel wideband RF system, nicknamed the barrier RF, has been designed, fabricated and installed in the Fermilab Main Injector. The cavity is made of seven Finemet cores, and the modulator made of two bipolar high-voltage fast solid-state switches. The system can deliver ±7 kV square pulses at 90 kHz. The main application is to stack two proton batches injected from the Booster and squeeze them into the size of one so that the bunch intensity can be doubled. High intensity beams have been successfully stacked and accelerated to 120 GeV with small losses. The problem of large longitudinal emittance growth is the focus of the present study. An upgraded system with two barrier RF cavities for continuous stacking is under construction. This work is part of the US-Japan collaborative agreement

Fast beam stacking using RF barriers

Two barrier RF systems were fabricated, tested and installed in the Fermilab Main Injector. Each can provide 8 kV rectangular pulses (the RF barriers) at 90 kHz. When a stationary barrier is combined with a moving barrier, injected beams from the Booster can be continuously deflected, folded and stacked in the Main Injector, which leads to doubling of the beam intensity. This paper gives a report on the beam experiment using this novel technology.Comment: 2007 Particle Accelerator Conference (PAC07

A Drug Abuse Curriculum Guide for Franklin Pierce High School

The purpose of this study was twofold: (1) to identify the need for a drug abuse program at Franklin Pierce High School, Tacoma, Washington; and (2) to develop a drug education curriculum guide

Hydrous Manganese Oxide Doped Gel Probe Sampler for Measuring In Situ Reductive Dissolution Rates. 2. Field Deployment

In situ rates of reductive dissolution in submerged shoreline sediments at Lake Tegel (Berlin, Germany) were measured with a novel hydrous manganese (Mn) oxide-doped gel probe sampler in concert with equilibrium gel probe and sequential extraction measurements. Rates were low in the top 8 cm, then showed a peak from 8 to 14 cm, with a maximum at 12 cm depth. This rate corresponded with a peak in dissolved porewater iron (Fe) at 11 cm depth. Below 14 cm, the reductive dissolution rate reached an intermediate steady value. Lower rates at depth corresponded with increases in operationally defined fractions of carbonate-bound and organic- and sulfide-bound Mn and Fe as detected by sequential extraction. Observed rates of reductive dissolution, which reflect a capacity for Mn reduction rather than actual rates under ambient conditions, appear to correlate with porewater chemistry and sequential extraction fractions as expected in early sediment diagenesis, and are consistent with previous measurements of in situ reductive dissolution rates. Significant downward advection in this bank filtration setting depletes the Mn and Fe oxides in the sediments and enhances the transport of dissolved Fe and Mn into the infiltrating water

The Variety of Variables in Automated Real-Time Refinement

The refinement calculus is a well-established theory for deriving program code from specifications. Recent research has extended the theory to handle timing requirements, as well as functional ones, and we have developed an interactive programming tool based on these extensions. Through a number of case studies completed using the tool, this paper explains how the tool helps the programmer by supporting the many forms of variables needed in the theory. These include simple state variables as in the untimed calculus, trace variables that model the evolution of properties over time, auxiliary variables that exist only to support formal reasoning, subroutine parameters, and variables shared between parallel processes

The thermo-mechanical degradation of ethylene vinyl acetate used as a solar panel adhesive and encapsulant

The thermal ageing of an Ethylene-vinyl Acetate (EVA) polymer used as an adhesive and encapsulant in a photovoltaic module has been investigated. The EVA is used to bond the silicon solar cells to the front glass and backing sheet and to protect the photovoltaic materials from the environment and mechanical damage. Using a range of experimental techniques, including Dynamic Mechanical Analysis, Differential Scanning Calorimetry and Thermo-Gravimetric analysis, it was possible to show a link between changes in mechanical properties with both the transient temperature and the degree of long-time thermal ageing. Importantly, it was possible to show that the ageing related property changes were likely due to long term structural changes rather than any modification of the chemistry of the material