Kenneth Trantham

An inline optical electron polarimeter

The design and operation of a simple inline optical electron polarimeter is presented. It is based on exchange excitation of ground state neon atoms. The electron polarization is determined from the degree of circular polarization of the subsequent 2p53p 3D3→2p53s 3P2 (6402 A) fluorescence. This device can characterize both longitudinally and transversely polarized electron beams in a nondestructive fashion, and is inexpensive and easily constructed.

Overview of the Brewing Process

In this chapter, we will explore the basic steps required in modern beer brewing in the USA. Much of what is presented here is discussed again in other chapters in greater detail. This chapter provides a sketch of the overall process and will aid us by providing a blueprint to follow as we explore these subjects. While there are some significant differences in the process steps taken for the homebrewer versus the industrial-scale brewer, the basic steps are the same. In the USA, the most common materials will be the focus of our overview. Other materials such as adjunct grains and fermentables, rice hulls and fillers, hop oils and isomerized extracts, artificial carbonation, and finings are frequently used. Their specific use will be covered as we explore the overall process steps in detail later in this text.

Failure to observe electron circular dichroism in camphor

Analogous to optical circular dichroism, it is possible to have electron circular dichroism, the preferential transmission of longitudinally polarized electrons through a chiral medium. Using stereoisomers of camphor vapor as a scattering target, we looked for this effect at incident electron energies of 1, 3, 5, 7, or 10 eV. Within our detection limit (~0.02%) we have not observed a spin-dependent asymmetric transmission.

Introduction to Brewing Science

When we think about making beer, what comes to mind? Often we rely on those images with which we are familiar, the TV ads showing brewers sitting around sampling their work or the server pulling a tap to dispense a beautiful yellow liquid into a glass. But there is more to the process than we see on the television. And the science behind that process is quite interesting. We will begin our look into the brewing process from the very beginning of civilization and build our understanding of the methods used today. Along our journey, we will uncover the science behind the scenes and gain a much deeper understanding of this very important beverage.

Quality Assurance and Quality Control

The brewing process is essentially complete when the beer is packaged. But is it really? In this chapter, we will explore the principles of quality control and assurance. These two principles are used by the brewer to ensure that the brewery operates with the highest standards. When coupled with total quality management or other guidelines, the brewery will reproducibly manufacture product that has the best chance of being sold to consumers.

Molecules and Other Matters

In this chapter, we will explore the basics of general and organic chemistry that are needed to understand what happens during beer brewing. Learning how to draw the structure of the compound will allow us to understand the function of those compounds and their likely role in brewing. To fully understand the entirety of general and organic chemistry would require two full years of study. Many texts can aid in that study, but here we will look into the basics from the brewers’ perspective.

The “Food” for the Brew

Brewing beer requires that we convert starches into sugars in order to ferment them. In this chapter, we will uncover the conversion of starches into sugars. This requires the modification of barley (primarily) into malt. The step is very important, because unmodified barley hinders our ability to make sugars later in the process. We will explore the actual processes that make malt and the equipment that is used in the process. In this chapter, we will also take a look at what some brewers consider to be the most important ingredient in making beer; water. We will examine the makeup of water and how its quality impacts the brewing process.

Cooling and Fermenting

After boiling, the wort is prepared for the fermentation stage by cooling it rapidly. This involves the use of a wort chiller. The liquid is then placed into a fermenter and yeasts are added. Fermentable sugars are converted into alcohol and carbon dioxide in this process. Uncovering the principles behind these processes reveals a wealth of theory in thermochemistry and physics. That will be the focus of this chapter.

Method for monitoring GaAs photocathode heat cleaning temperature

Before a GaAs photocathode can be activated to achieve a negative electron affinity condition, the GaAs crystal must be cleaned. This is most commonly done by ohmic, radiative, or electron bombardment heating. We report a new technique to monitor the temperature of heated GaAs photocathodes by observation with a camera. The method is robust and yields the same temperatures for different GaAs samples heated using different methods in different mounting configurations.