We have developed and commissioned an angle-resolved photoelectron spectrometer, based on the electron time-of-flight concept, for hard x-ray photon diagnostics at the European Free-Electron Laser. The instrument provides users and operators with pulse-resolved, non-invasive spectral distribution diagnostics, which in the hard x-ray regime is a challenge due to the poor cross-section and high kinetic energy of photoelectrons for the available target gases. We report on the performance of this instrument as obtained using hard x-rays at the PETRA III synchrotron at DESY and the SASE1 beamline at the European XFEL. We demonstrate a resolving power of 10 eV at incident photon energies up to 20 keV.
In this paper, we present recent progress on polarization optics using the 1-BM beamline at the Advanced Photon Source,
Argonne National Laboratory. Beamline 1-BM was recently repurposed for optics and detector testing. SHADOW
software, a ray-tracing program for the simulation of optical systems of synchrotron radiation beamlines, is used to
model the beamline. In this paper, we present optical ray-tracing studies for test set-ups that take advantage of the
polarization variation of the bending magnet radiation above and below the horizontal plane of the beamline.
The initial result of using a single 2-D checkerboard phase-grating Talbot interferometer as a feed-back loop sensor
element of an adaptive x-ray mirror system is reported. The test was performed by measuring the surface profile of a
deformable Pt coated Silicon mirror at five different actuation states. The reflected beam was detected at the fractional
Talbot distance of a π/2 phase grating. The measured interferograms were de-convolved using the spatial harmonic
imaging technique to extract the phase and amplitude of the reflected wavefront. The wavefront was then propagated to
the mirror center to retrieve the surface profile of the mirror. The activation of a single actuator was easily detected from
the reconstructed surface profile of the mirror. The presented results indicate that the single phase-grating x-ray Talbot
interferometer is capable of sensing nano-meter scale profile changes of an adaptive mirror.
Kirkpatrick-Baez (K-B) mirrors [1] are sophisticated x-ray micro- and nano-focusing tools for synchrotron radiation applications. A prototype of a modular x-ray K-B mirror mount system has been designed and tested at an optics testing beamline, 1-BM at the Advanced Photon Source (APS), Argonne National Laboratory (ANL). This compact, costeffective modular mirror mount system is designed to meet challenging mechanical and optical specifications for producing high positioning resolution and stability for various scientific applications with focused hard x-ray beams down to the 100-nanometer scale. The optomechanical design of the modular x-ray K-B mirror mount system as well as the preliminary test results of its precision positioning performance are presented in this paper.
X-ray monochromators, made of single crystals or multilayer coatings, are the most common optical components
on many synchrotron beamlines. They intercept the broad-spectrum x-ray (white or pink) beams generated by the
radiation source and absorb all but select narrow spectral bands of x-rays, which are diffracted according to
Bragg’s Law.
With some incident beam power in the kW range, minimizing thermally induced deformation detrimental to the
performance of the device necessitates the design of optimally cooled monochromators.
Monochromator substrate designs have evolved, in parallel with thermal loads of the incident beams, from simple
blocks with no cooling, to water cooled (both contact -cooled and internally cooled), and to cryogenically cooled
designs where the undesirable thermal distortions are kept in check by operating in a temperature range where the
thermomechanical properties of the substrate materials are favorable. Fortuitously, single-crystal silicon at
cryogenic temperatures has an exceptionally favorable combination of high thermal conductivity and low thermal
expansion coefficient.
With further increases in x-ray beam power, partly as a result of the upgrades to the existing synchrotron
facilities, the question arises as to the ultimate limits of liquid-nitrogen-cooled silicon monochromators’ ability to
handle the increased thermal load.
In this paper, we describe the difficulties and begin the investigation by using a simple geometric model for a
monochromator and obtain analytical solutions for the temperature field. The temperature can be used as a proxy
for thermally induced deformation. The significant role of the nonlinear material properties of silicon is
examined.
Here we report on the effort to develop a hard x-ray grating interferometry technique for application to hard x-ray optics
and wavefront characterization at the Advanced Photon Source (APS), Argonne National Laboratory, USA. We will
mention the motivation for developing an x-ray interferometer at the APS and discuss the design of the interferometer.
We will also describe the efforts in fabricating 2-D gratings and a new type of grating having nanometer periods for
high-energy x-ray applications. The preliminary results obtained using x-ray Talbot interferometers built at APS, using a
broadband (pink) beam and a monochromatic beam demonstrate the importance of this tool as a metrology instrument
for optics and beam wavefront diagnostics.
We have developed a series of new dye bombesin conjugates for site-specific absorption and fluorescence imaging of human prostate and breast cancers. Bombesin (BBN), an amphibian analog to the endogenous ligand, binds to the gastrin releasing peptide (GRP) receptors with high specificity and affinity. Previously, we developed an Alexa Fluor 680-GGG-BBN peptide conjugate which demonstrated high binding affinity and specificity for breast cancer cells in the in vitro and in vivo tests (Ref: Ma et al., Molecular Imaging, vol. 6, no. 3, 2007: 171-180). This probe can not be used as an
absorption probe in near-infrared imaging because its absorption peak is in the visible wavelength range. In addition, site specific longer wavelength fluorescent probe is desired for in vivo molecular imaging because long wavelength photons penetrate deeper into tissue. The new absorption and fluorescent probe we developed is based on the last eight-residues of BBN, -Q-W-A-V-G-H-L-M-(NH2), and labeled with AlexaFluor750 through a chemical linker, beta-alanine. The new probe, Alexa Fluor 750-BetaAla-BBN(7-14)NH2, exhibits optimal pharmacokinetics for specific targeting and optical
imaging of the GRP receptor over-expressing cancer cells. Absorption spectrum has been measured and showed absorption peaks at 690nm, 720nm and 735nm. Fluorescent band is located at 755nm. In vitro and in vivo investigations have demonstrated the effectiveness of the new conjugates to specifically target human cancer cells overexpressing GRP receptors and tumor xenografts in severely compromised immunodeficient mouse model.
Multimodality molecular imaging that combines anatomical and functional information has shown promise in
development of tumor-targeted pharmaceuticals for cancer detection or therapy. Most multimodality imaging techniques
are based on nuclear imaging modalities and MRI or CT. Fluorescence molecular tomography (FMT) is an emerging
optical modality for non-invasive functional imaging and early diagnosis of carcinoma. Three-dimensional FMT can
differentiate tissue physiological changes in vivo to provide functional information when used in conjunction with cancer
cell selectively targeted probes. In this study, we present the design of such a system for multimodality molecular
imaging. A frequency domain radio frequency technique based on commercial amateur radio equipment has been
developed. A heterodyne method is used to transfer a low frequency oscillation into a single-side-band at radio
frequency. The difference in phase, caused by fluorescence photon density wave, is detected between a transmitting
fiber and a receiving fiber bundle, and then measured at lower frequency after demodulation. To achieve multimodality
molecular imaging, a new fluorescent labeled tumor-targeting probe, fluorescent bombesin conjugates, has been
developed with high affinity and specificity for targeting breast cancer cells. The developed multimodality fusion
strategy will provide increased sensitivity/specificity for cancer cells, with respect to any single imaging modality.
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