March 2004 NSLS-II Workshop: Nanoprobe/Imaging Breakout Session

Short contributions were made by Tony Lanzirotti, Tobias Beetz, Keith Jones, Benjamin Hornberger and Avraham Dilmanian. The attendees had the opportunity to ask questions after each talk.

Cecilia Sanchez-Hanke welcomed the participants and gave a comprehensive overview of the imaging and nanoprobe sections in the NSLS-II proposal.

Peter Cloetens described hard x-rays tomography at ESRF with nanoprobe beams and phase contrast methods. He pointed out the use of KB mirrors to focus the beam to 86 nm (vertical) and 83 nm (horizontal=source size). He claimed that he had 10¹² photons/sec in that spot. Peter Takacs asked what was so particular in the mirrors to get such small focal spot size, and what would be required to get to even smaller sizes. The answer was that the source size could be a limit, and that the mirrors needed to be more "perfect" to get smaller sizes, i.e. figure errors are still significant. Peter Cloetens also mentioned the development in detectors at ESRF with the new FreLoNZ (frame transfer) fast read-out CCD camera (16Hz).

Harald Ade's talk focused on soft x-ray imaging in the real and reciprocal space. He suggested that NSLS-II is a source for imaging and nanoprobe. He asked for an EPU (switching polarization vertical/horizontal) to be sensitive to different orientations of the polymers (and circular right/left for magnetic systems). No references in how fast it should switch. For the detection of small amount of material with fluorescence with soft x-rays, a beamline energy range 150-2000 eV is optimum. On the spatial resolution, soft x-ray zone plates are close to the operational limit at current sources, but the aspect ratio between length and inter-space can be increased on sources with higher flux like NSLS-II. On the "Resurrection of SPEM", spatial resolution down to 2 nm is possible in photoemission aberration free microscope, while 10 nm spatial resolution is possible with zone plates.

Dean Chapman showed the wide spectra of medical imaging and therapy applications using synchrotron radiation. Some applications require a superconducting wiggler to reach 90 keV. Energies for DEI should be easy to reach but MRT requires much higher magnetic field on wiggler (10 Tesla at the Canadian Light Source) and that could present problems interacting with the electron beam at CLS, and maybe at NSLS-II (large B, period K of 10, wide fan). He pointed out that in case of having a medical therapy/imaging beamline, medical dedicated personnel and leadership is essential. Timing, as far as the ring is concerned, will is not an issue, but typically needs to be faster then a heartbeat, which requires improvements in the detection systems. Therapy will require beams of the order of 1 mm to 25 µm.

Short contributions

Tony Lanzirotti on environmental science: For performing dendroanalysis, higher flux allowed by NSLS-II will reduce acquisition time from 7 hours to 1 hour. They want to see 10 µm particles distributed in metals (mapping) as well a large sized samples of the order of centimeters and larger. One problem is data transfer from the detector to the computer, around 2 Gbits in a fast way. He pointed out that probably will be good to have two beamlines dedicated for nanoprobe, an ID beamline and a BM where with the gain in brightness and flux from NSLS-II will allow to perform a lot of experiments and "screen" the samples.

Tobias Beetz on diffraction imaging: Advantage of diffraction imaging is optic free beamline. An undulator is preferred to gain in data acquisition time. Currently at the NSLS acquisition time is days, as compared to hours at ALS. At the NSLS-II, this is expected to be approximately 1 hour. There will also be detector readout issues to realize this improvement. Biological samples may suffer from problems with radiation damage.

Keith Jones on computed microtomography: He described the advantage of NSLS-II on element-specific detection with fluorescence of small concentrations of elements.

Benjamin Hornberger proposed to perform, at NSLS-II , Xanes in Phase, Imaging with zone plate's 3rd order (9 times less intensity, 3 times better energy resolution). Harald Ade answered that it could be difficult to do. Optics improvement in "large" diameter zone-plates may be able to work with larger working distances. Current detectors and detectors faster than MHz counting rates are preferred.

Avraham Dilmanian proposed a medical facility for microbeam radiation therapy as a test bed for a future new sources dedicated to radiation therapy. He agreed with Dean Chapman that such a facility/beamline requires medical personal interested in it. Small beams with high energies are preferred for this research.

Last Modified: January 31, 2008
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