2007 Photos of the Month
November
An exciting new project just beginning in the Walsworth group is the development of a laser-based astro-comb. Recently, Ron, David, and Chih-Hao visited the MMT Observatory in Arizona, a 6.5-meter-diameter optical telescope located on the summit of Mt. Hopkins, 30 miles south of Tucson, Arizona. The telescope is operated jointly by SAO and the University of Arizona, and includes a suite of advanced wide-field imagers and spectrographs developed and deployed for the MMT by SAO scientists. The astro-comb collaboration was at the telescope looking for siting locations for the astro-comb as well as calibrating the collecting efficiency of the dome screen. Ron is pictured standing in front of the MMT telescope. Visible in the foreground on Ron’s right side is the rail along which the telescope slides to change the altitude at which it points. The fiber bundle carrying light from the secondary focus (over Ron’s left shoulder) to the spectrographs.
After a couple of months hiatus in the Walsworth group laboratory (due to a fire-related accident), work is starting to begin again in the lab. The 4.7 T NMR console suffered the most smoke-related damage, and was recently replaced. In the photo above, Ron is shown pretending he can make fine adjustments to the tuning of the NMR spectroscopy probe in the superconducting 4.7 T magnet during the installation of the replacement console.
September
A number of new experiments are beginning in most areas of the group. In our ongoing collaboration with Charlie Marcus’s group in the Harvard Physics Department, we have been studing methods for enhancing the nuclear spin polarization of silicon nanoparticles in order to explore their potential as molecular imaging agents. We recently relocated a high-field cryostat from the Marcus lab to the Walsworth lab in order to hyperpolarize silicon particles at ultra-low temperature and high-field and perform initial MRI experiments with solid silicon particles.
August
A number of new experiments are beginning in most areas of the group, and we have been joined by a new collection of graduate students and postdocs for 2007-08. Paul Stanwix is a new postdoc who has recently joined the group, and who with Ross now brings our tally of Australians to two in the group! Paul is shown here learning about the Dual Noble Gas Maser in the Walsworth Group laboratory. Alex Glenday is explaining the operation of the apparatus to be used in a new series of experiments continuing the search for Lorentz-violating couplings to the neutron.
July
A number of new experiments are beginning in most areas of the group, and we have been joined by a new collection of graduate and undergraduate students for 2007-08. Masha Baryakhtar is a new undergraduate who is learning about the stored light experiments that are performed in Walsworth Group optics laboratory. She is shown here making adjustments to some of the optics hardware used in the stored/slow light experiments.
March – May are usually busy travel months for many group members, as a number of annual conferences important to our work all align on the calendar. Ron often attends the APS March meeting in March, while Ross and perhaps an NMR/MRI student are usually at the Experimental NMR Conference in March or April. We also periodically attend the International Society for Magnetic Resonance in Medicine annual meeting, traditionally in May. Finally, the travel season is rounded out with the APS Division of Atomic and Molecular Physics conference (DAMOP) which Ron, David and many of the students in the atomic clock/optics areas of the group attend. Here, Mason is shown enthusiastically presenting some of the group’s latest novel atomic clock results. .
June
March – May are usually busy travel months for many group members, as a number of annual conferences important to our work all align on the calendar. Ron often attends the APS March meeting in March, while Ross and perhaps an NMR/MRI student are usually at the Experimental NMR Conference in March or April. We also periodically attend the International Society for Magnetic Resonance in Medicine annual meeting, traditionally in May. Finally, the travel season is rounded out with the APS Division of Atomic and Molecular Physics conference (DAMOP) which Ron, David and many of the students in the atomic clock/optics areas of the group attend. Here, David is shown in an animated (and slightly lubricated) conversation relating to some of the group’s latest stored-light results.
March – May are usually busy travel months for many group members, as a number of annual conferences important to our work all align on the calendar. Ron often attends the APS March meeting in March, while Ross and perhaps an NMR/MRI student are usually at the Experimental NMR Conference in March or April. We also periodically attend the International Society for Magnetic Resonance in Medicine annual meeting, traditionally in May. Finally, the travel season is rounded out with the APS Division of Atomic and Molecular Physics conference (DAMOP) which Ron, David and many of the students in the atomic clock/optics areas of the group attend.
May
Our biomedical and materials science studies using MRI of hyperpolarized noble gases have been performed using in-house designed and built noble gas polarization apparatus. In recent times, Matt has been responsible the design and construction of these systems, and now Chih-Hao is quickly learning about them. We have programs to improve both the polarization rate (especially in 3He) and the total polarization level attainable (especially in 129Xe). However, every once in a while, our PI, Ron heads back to his laboratory ancestory and pretends he can play with the polarizers. Wearing adequate safety equipment, Ron is attempting to operate the helium polarizer, while everyone else has left the room!
April
Our development of an open-access, very-low-field MRI system for posture-dependent human lung imaging has been mentioned in a syndicated Columbia News Service article that has since appeared in a major US city newspaper. The article, describing the problem of claustrophobia commonly encountered by many patients undergoing traditional MRI scans in clinical scanners, highlights newer technologies that are producing more open MRI scanners that can be tolerated by wider sections of the public. The article originally appeared on the Columbia News Service website in late February, and includes quotes from Ron describing the user-friendly nature of our open-access scanner. “The patient can simply walk in or sit down to be scanned,” said Ronald Walsworth, the research team leader. Since that time, the report has appeared in the Orlando Sentinel in Orlando, FL. An abbreviated form of the story also appeared in the Anniston Star, which serves Anniston and northeastern Alabama! This recognition follows articles on our first-generation open- access scanner, which appeared in scientific magazines in 2004.
March
New glass cells have been designed recently for noble gas spin-exchange-optical pumping experiments in the Walsworth Group lab at the Center for Astrophysics. Matt has designed these cells with strengthened glass ends that withhold the high pressures these cells must contain, along with extended capillaries between the body of the gas cell and the valve where gas enters the cells. This capillary acts as a diffusion limiter to prevent helium atoms interacting with the valve surface and depolarizing during the optical-pumping experiment to enhance the gas spin polarization. These particular cells are used for hyperpolarized helium production, preparing gas for our open-access, posture-dependent human lung imaging studies.
Matt is shown exhibiting his glass-blowing skill in the Walsworth Group lab at the Center for Astrophysics. He is attaching glass side-arms to noble-gas polarization cells, which will enable rubidium metal to be placed in the cell. Rubidium is a vital intermediary in the spin-exchange optical-pumping process used to hyperpolarized helium and xenon gas for high-sensitivity MRI experiments. This particular cell is being prepared our helium polarization apparatus, which prepares gas for our open-access, posture-dependent human lung imaging studies.
January
We were recently awarded over $500,000 from the NSF to improve our current noble-gas polarization systems and develop improved polarizers which operate with higher throughput or yield more highly polarized gas. One key new technology to be employed in spin-exchange optical pumping of 129Xe and 3He is the use of laser diodes with their typical broad spectral output of ~ 2 nm narrowed to ~ 0.3 nm by incorporation of Volume Bragg Gratings. The narrowed output closely matches the Rb absorption wavelength, and can result in close to 100% of laser light being absorbed for noble gas polarization, rather than ~ 5 – 10% in traditional laser diode arrays. Much of our effort in this area has been guided by collaboration with Dr. Mike Barlow from University of Nottingham in the UK. Mike has visited our lab and has been able to arrange long-term loan of some of his excess laser equipment. Here, Mike is shown in our lab, optimizing a free-standing laser-diode/VBG combination he assembled in Nottingham, and shipped to our lab for use with our laser-polarized xenon apparatus.