P.L. Jolivette

Experimental verification of the Heisenberg uncertainty principle—An advanced undergraduate laboratory

The Heisenberg uncertainty principle can be experimentally demonstrated by combining a Mossbauer experiment with a measurement of a nuclear lifetime. The senior undergraduate students perform a Mossbauer experiment to measure the energy width of the 14.4 keV level of 57Fe followed by measurements of coincident γ rays to determine the lifetime of the level. The experiments are designed to emphasize that the uncertainty principle is inherent in the wave function rather than resulting from the measurement process.

Charge symmetry tests: Final charge symmetry violation results from IUCF

In the context of ‘‘Charge Symmetry Tests’’, we report final results from an n‐p scattering experiment completed at IUCF providing definitive evidence for charge‐symmetry‐breaking (CSB) in the strong interaction. Our results are well described by meson‐exchange calculations which include ρ−ω mixing in addition to the n‐p mass difference effect on one‐boson exchange.

Investigation of 8B structure at low excitation energies

The 7Be(p,γ)8B reaction plays a very important role in nuclear astrophysics, since it is the source of the high-energy solar neutrinos. However, it is not possible to measure the cross section of this reaction at solar energies (20 keV) directly so one must rely on extrapolations from higherenergy data. It is clear, that extrapolation procedure can be strongly influenced by higher lying broad resonances [1]. This makes knowledge of the structure of 8B nucleus crucial for the correct interpretation of the results of the direct radiative capture measurements.

The restructured “advanced laboratory” at Hope College—A step toward independence

The advanced physics laboratory at Hope College is a majors course focusing on experimental physics. This course teaches not only experimental techniques, but also experimental design, implementation and analysis. The students are asked to design experiments using existing equipment (such as the Hope College 2MV Van de Graaff accelerator) to address a physical question posed by the instructors. Their experimental plan is reviewed by a program advisory committee (the instructors for the course). Students learn that the planning state can be as important as the actual experiment. They learn how to write a report about an unexpected or less than perfect result. The challenge for the instructors has been finding a way to help the students to become “independent” without frustrating them in their early attempts. This paper will discuss the structure of the course and give examples of the accelerator-based experiments used to help build independent research skills.