THE ELECTRONIC ALADDIN NEWSLETTER NO. 33

July 2003

1. High School Students Conduct Remotely-controlled Experiments at the Synchrotron Radiation Center


Eight chemistry students from Evansville High School performed experiments at the Synchrotron Radiation Center (SRC) on April 14th after touring the facility with their teacher Rick Cole. During their visit they set up a program on one of the beamlines which allowed them to control the experiment and take data over the internet from their school. Over the next week the students continued to take data and analyze the results. On May 5th the students returned to SRC and presented the results of their experiments in a poster session.

The AP chemistry students used the SRC Mark V beamline to take data of four filters making use of a gold diode detector. The four filters were made of elements of Beryllium, Boron, Aluminum, and Titanium. Each student had the opportunity to take data of a different filter which provided an understanding of the experimental setup. The data was collected using Labview software, which the students also learned how to operate remotely via the internet so that they could take data from their high school and homes.

The remote interface consisted of the Labview software and a web server connected to the internet through which the students could enter the range of energies to scan, step size, and averaging parameters. They could also view, in real time, a graph of data being taken. After the scan was completed the students were able to download the data for analysis.

On May 5th the students presented their work at the SRC during a poster session. Each student focused on a different aspect of the experiment. Calculations of transmittance and absorption were presented for each of the four filters. Comparisons between the data collected and the theory (Bohr model) were presented with an assessment of any differences. Posters include explanations of how the Aladdin electron storage ring works, as well as explaining the details of their experimental setup.

The remote experiment was part of the active outreach program at SRC which includes providing research experiences to middle and high school students in order to foster their interest in science and science careers. The project was organized by SRC outreach coordinator Chris Moore, together with Mark Bissen and Chad Hewitt from the SRC and Rick Cole, the advanced placement chemistry teacher at Evansville High School. This method of interacting with high school students holds promise as a way of allowing students to experience how data is taken in the real world and also mesh with school curriculum without disrupting it. The SRC plans to improve this activity and involve more local high schools around the area in similar projects.

2. Multiple Superconducting Gaps in MgB2 Unambiguously Established


Juan Carlos Campuzano, a member of the SRC scientific directorate, together with his former student Adam Kaminski and several researchers from Japan and elsewhere have uncovered evidence that unambiguously proves that the metallic superconductor Magnesium diboride (MgB2) has a two-band superconductivity mechanism.

The transition temperature for MgB2 is 39 K, which is the highest known Tc for a metallic superconductor. The cause of this anomalously high Tc is the subject of intensive study because of its importance to understanding the fundamental physics of superconductivity as well as for its potential industrial applications. The key to understanding superconductivity lies with the superconducting energy gap associated with the formation of the superconducting pairs. Previous experiments suggested that there are two kinds of superconducting gaps in MgB2, in contrast to both conventional and high-Tc superconductors. However, these experiments were unable to provide a clear demonstration of the two gaps because they lacked the ability to resolve the momentum of the superconducting electrons. Using high-resolution angle-resolved photoemission spectroscopy (ARPES) Campuzano and his associates were able to gather direct experimental evidence for the two-band superconductivity in MgB2, by separately observing the superconducting gaps of the sigma and pi bands (as well as a surface band). The gaps have distinctly different sizes, which proves that MgB2 is a two-gap superconductor. The results of this research were published in the May 2003 issue of Nature.

 

3. Environmental Infrared Workshop A Great Success

A workshop on infrared spectromicroscopy, focusing on environmental applications, was held at the University of Wisconsin-Madison Synchrotron Radiation Center May 28-30, 2003. This workshop was designed for scientists working in areas of environmental research who are users or potential users of synchrotron-source infrared spectromicroscopy. Twenty-seven researchers attended the workshop which was sponsored by and held at the SRC. It was organized by Professor Carol Hirschmugl (Department of Physics, University of Wisconsin-Milwaukee), Professor William Bleam (Department of Soil Sciences, University of Wisconsin-Madison), and Dr. Bob Julian (SRC staff scientist). The three-day workshop consisted of invited presentations, lectures, tutorials, and hands-on experience at the SRC infrared beamline.

The workshop began with several invited presentations which included an introduction to infrared synchrotron spectromicroscopy by Prof. Hirschmugl, a discussion of identifying fine mineral grains using IR spectromicroscopy by George Flynn (SUNY- Plattsburgh), an analysis of quantification using IR spectromicroscopy by Lisa Miller (Brookhaven National Laboratory) and an overview of environmental applications by Wayne McKinney (Lawrence Berkeley National Laboratory). A banquet was held in the evening followed by a panel discussion with the invited speakers.

The second day consisted of lectures and tutorials on infrared spectromicroscopy. The first session was designed to give workshop participants an introduction to the overall use of infrared radiation and spectroscopy. The second session dealt with the use of an infrared microscope in a general laboratory situation. This was followed by a session on spectromicroscopy using a synchrotron as the infrared source, with emphasis placed on applications where the synchrotron was absolutely necessary.

The lectures were followed by several tutorials designed to make the participants think about what kinds of research could be done with general laboratory spectromicroscopy and what could only be accomplished with infrared synchrotron radiation (IR SR). The lectures were followed by a presentation on the computer software for data acquisition and analysis. Running in parallel to these lectures, participants who were already familiar with IR SR were able to use the SRC infrared beamline to measure samples of materials specific to their areas of environmental research.

During the third day, the participants were divided into small groups for hands-on experience on the infrared beamline. Each group spent approximately three hours looking at sample handling, data collection setup, simple point measurements and performing a practical mapping exercise. Evaluations of the workshop by participants were universally positive.

 

4. Notes:

This summer SRC is hosting four undergraduate students through the Research Experience for Undergraduates (REU) program. The program is designed to provide undergraduates the opportunity to do research in laboratories under the tutelage of experienced researchers. Clay Bennington, Midland Lutheran College, is looking at factors that affect the stability and lifetime of the Aladdin electron beam. His mentor is Joseph Bisognano. Hector Campa, University of Texas at El Paso, is working with the SRC outreach coordinator Chris Moore helping design activities for visiting 7th graders during the summer. He is also working on a series of experiments that will demonstrate optical phenomena of Synchrotron beamlines. Marleen Martinez, University of Washington, is working on experiments that will help explain and understand the multiple photoionization of Lithium molecules. Her mentor is Ralf Wehlitz. Rene Sandin, University of Puerto Rico, is using Infrared Spectromicroscopy to study pollen samples with the aim of distinguishing individual pollen grains. His mentor is William Bleam.

Congratulations to Christian Ast who obtained his Ph.D. in Physics from UW-Madison under the direction of Hartmut Höchst. His dissertation was on the electronic structure of Bi(111) which he studied using angle-resolved photoemission spectroscopy. His last day at SRC will be July 31, 2003 after which he will be going to the Max-Planck-Institute for Solid State Research in Stuttgart, Germany.

Congratulations to John Joyce of Los Alamos National Laboratory for his election to the chair of the SRC User Advisory Committee.

On August 4, 2003 approximately fifty physics teachers will tour the SRC facility as part of the activities available to the participants of the American Association of Physics Teachers annual meeting held in Madison August 2-5.

The SRC Users’ Meeting has been moved to Saturday, October 25, 2003. Instead of an accompanying one-day workshop, multi-day workshops on special topics along the lines of the recently held IR workshop are planned for other times of the year. Users are welcome to suggest topics or volunteer to organized such an event

The SRC Open House will be on September 14, 2003. This event is open to the public and families are encouraged to attend.