Location
Harrisonburg, VA
Start Date
16-5-2012 9:20 AM
End Date
16-5-2012 9:40 AM
Description
A high speed X-Ray chopper (mechanical shutter) was developed for sub microsecond time-resolved photocrystallography using a synchrotron source. Based on a rim-slotted titanium wheel rotating at a nominal 60,000 r/min, the device has an upper bound timing alignment (aperture passage compared to source pulse edge) jitter of 23 nsec RMS and has been operated consistently at jitters as low as 7 nsec RMS. The spindle was derived from a commercial turbo-molecular pump whose drive was adapted in a fairly simple manner to enable fine control by a secondary wheel phase regulator using conventional, off-the-shelf components. Because the spindle uses magnetic bearings, there are no lubricants and the system can be operated in a very high vacuum without recourse to seals and without concern for migration of contaminants.
Presenter Bio
Eric Maslen Professor & Department Head Integrated Science & Technology, James Madison University
Eric Maslen earned his B.S. in mechanical engineering from Cornell University in 1980 and his doctorate, also in mechanical engineering, from the University of Virginia in 1991. He worked in industry and was a Peace Corps volunteer between degrees, joined the faculty of UVA in 1990 and was promoted to full Professor in 2003. He joined the faculty of the Department of Integrated Science and Technology at James Madison University as Department Head in 2010. Dr. Maslen’s research is in controls, magnetics and rotating machine dynamics with special application to magnetic bearings. He holds seven patents, and serves actively as a consultant to industry, government agencies, and other academic organizations.
Included in
Development of a 60,000 RPM X-ray Chopper with 25 nsec Phase Jitter for Crystallography
Harrisonburg, VA
A high speed X-Ray chopper (mechanical shutter) was developed for sub microsecond time-resolved photocrystallography using a synchrotron source. Based on a rim-slotted titanium wheel rotating at a nominal 60,000 r/min, the device has an upper bound timing alignment (aperture passage compared to source pulse edge) jitter of 23 nsec RMS and has been operated consistently at jitters as low as 7 nsec RMS. The spindle was derived from a commercial turbo-molecular pump whose drive was adapted in a fairly simple manner to enable fine control by a secondary wheel phase regulator using conventional, off-the-shelf components. Because the spindle uses magnetic bearings, there are no lubricants and the system can be operated in a very high vacuum without recourse to seals and without concern for migration of contaminants.
