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Flux is a simple yet key indicator of overall beamline alignment. For many synchrotron measurements, the energy resolution and reproducibility are important characteristics as well. However, many beamlines do not have diffractometers capable of measuring the energy resolution in the experimental hutches. For absolute flux measurements, we have found that thickness calibrated Si photodiodes make very convenient, robust detectors capable of handling a wide flux range. For measuring the energy resolution, we have developed a simple, portable instrument analyzer applicable to any beamline with a scanning monochromator. This same instrument is capable of measuring the energy stability and reproducibility as well. We have used these to characterize many of the beamlines on the NSLS X‐ray ring, and will present the methods and our experience to date to demonstrate their usefulness.

We developed a fluorescence‐type monochromatic X‐ray beam‐position monitor (X‐BPM) with high‐spatial resolution for end‐station experiments at the initial project beamlines of the NSLS‐II. We designed a ring array of multi‐segmented Si PIN‐junction photodiodes to use as a position sensor. Further, we integrated a low‐noise charge‐preamplification HERMES4 ASIC chip into an electronic readout system for photon‐counting application. A series of precision measurements to characterize electronically the Si‐photodiode sensor and the ASIC chip demonstrated that the inherent noise from the detector system is sufficiently low to meet our stringent requirements. Using a Gaussian beam, we parametrically modeled the optimum working distance to ensure the detector’s best performance. Based upon the results from the parametric modeling, prototypes of the next versions of the X‐BPM are being developed. In this paper, we describe the methodology for developing the new compact monochromatic X‐ray BPM, including its instrumentation, detector modeling, and future plan.

The paper describes two detectors designed specifically for the SPPS ultrafast x‐ray source, one of which provides 2‐D position and intensity information, and the other acts as a low‐noise point detector for diffraction experiments. The beam position monitor (BPM) was used as a reference detector for most of the experiments performed there, and the point detector was used for pump‐probe experiments involving phonons in bismuth and on photosensitive metal‐organic crystals. The schedule for development of these detectors was extremely tight, so as much as possible we used available designs for amplifiers etc.

We present some measurements of nuclear fluorescence which were made while exploring the potential of a unique source of very hard x‐rays which was installed at ESRF until recently. It produced radiation of energies up to 1MeV. In this range there are many nuclear resonances, and so we made a small survey of some plausible candidates to see if they could indeed be excited using this source. Along with short‐lived resonances, we were also able to indirectly populate long‐lived isomeric states in several nuclei. Thus, simply exposing the samples to the white beam for a period of time caused them to be activated. The samples could them be removed from the beam and their emissions observed using an energy‐resolving detector. Isomeric states in isotopes of indium, cadmium and silver were excited and their subsequent decay observed.

The SPPS and LCLS are next‐generation light sources which will produce ultra‐short x‐ray pulses a few 10’s of femtoseconds long, with large numbers of photons per pulse. These sources will enable new types of x‐ray experiments, but will require new approaches to optical instruments. We present here a spectrograph tailored for use with such sources, allowing the small beam cross‐section to be spatially dispersed by means of a curved asymmetric Brag reflecting crystal. The design allows for an adjustable energy range by changing the radius of curvature within certain limits. Although inspired by these new sources, the device is also well adapted to conventional synchrotron radiation beamlines. It is significantly more compact than conventional wavelength‐dispersive devices, and has resolution advantages.

The SPPS and LCLS are next‐generation light sources which will produce ultra‐short x‐ray pulses a few 10’s of femtoseconds long, with large numbers of photons per pulse. The development of instruments to characterize the temporal properties of these beams is of significant interest. We present in this paper a concept and initial experiments towards the fabrication of an x‐ray interferometer suitable for this purpose. It makes use of the temporal focusing properties of the T‐2T‐T Bonse‐Hart interferometer to minimize the influence of the time‐dispersion of the instrument on the overall response function. Separate path‐length shifters based on an elastically deforming perfect crystal device are used to scan the time delay. Path‐length differences of up to 0.1mm should be possible using this shifter design. An advantage of this design compared to others is that there is in principle no limit to the possible path length shift.

As diffraction experiments in materials science move towards using harder x‐rays, the need for efficient multi‐detectors in the form of 1‐ and 2‐D arrays is felt. Silicon technology is not suitable for this, and germanium has the complexity of requiring cryogenics. Cadmium Zinc Telluride has emerged as the most promising compound for such applications. We describe our efforts towards providing a 1‐D strip detector suitable for high‐energy diffraction.

In order to meet the challenges of EXAFS and XANES spectroscopy of dilute systems, a custom integrated circuit has been fabricated which integrates 32 complete energy resolving photon counting chains onto a 6mm × 4mm chip. This paper reports on initial tests of a 96‐element detector implementation using low‐leakage diodes fabricated at BNL, and on our plans for a 384‐channel version. This large array will initially also use the same diodes but eventually will use a hexagonal drift‐detector array. The ASIC is read out through an embedded microcontroller device, and a software package has been written to allow highly automated setup of the entire system and straightforward integration into standard data acquisition packages.

Molecular dynamics simulations of proteins and lipid bilayers give detailed information on molecular motions on a timescale of up to a microsecond. Collective motions of proteins are thought to play a functionally important role in many water‐soluble proteins and simulations of potassium channel structures show that ion transport might be linked to structural fluctuations in key areas of the protein. I describe simulations of two model channels —a channel consisting of parallel alpha‐helices formed by the antimicrobial peptide alamethicin, and the bacterial porin OmpF, a large beta‐barrel protein that forms three water‐filled pores that allow transport of small molecules. Structural fluctuations in alamethicin during ion transport are hypothesized to be a possible source of high‐frequency noise observed in single‐channel conductance measurements. In a model of the alamethicin channel on a 100 ns time scale almost all the structural fluctuations are in individual helices with no evidence for collective mot...

For several years we have explored the use of hard x-rays for a broad range of lithographic applications. The high energy available from the NSLS x-ray ring (E>15 keV) allows the exposure of resist up to several cm thick, while maintaining micron level precision. The high flux and close proximity to the source at this machine make it possible to achieve workable exposures on realistic time scales, enabling production work. In addition to the conventional two-dimensional exposure schemes, we have demonstrated methods for achieving fully figured three dimensional objects with internal re-entrant geometry. Users from outside BNL have been sufficiently successful with their work at our prototype beamline (X-27B) that we have initiated the construction of a dedicated exposure station (X-14B) for High Aspect Ratio Precision Manufacture. An overview of our previous work as well as the current status of the new beamline will be described.