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We have designed, built, and tested a climate-controlled, radiation-shielded incubator cabinet for the purpose of analyzing the effects of low-dose x-ray radiation on biological tissues and cell cultures. Bremsstrahlung x rays incident on exchangeable fluorescence plates produce strong, quasi-monochromatic radiation directed toward a small container of biological samples. The x-ray source, sample, and detector are enclosed in an incubator-maintaining the optimal environment for biological samples to increase longevity to a maximum of 72 h. To demonstrate the capabilities of the setup, an example experiment is presented. Rat vascular smooth muscle cell growth was observed after irradiation with characteristic x rays of iron, copper, and calcium to impart doses of 2 mGy each. Cultures show significant spectrum dependent increases in cell number over controls at 48 h after irradiation. The experiment lends credence to the efficacy of the apparatus and shows promise for future low-dose bio-radiation studies.

A flexible spectrograph for the investigation of soft X-ray spectra in the range between 1 nm and 20 nm is presented. Based on two variable-line spaced reflection gratings, the design enables stand-alone operation, the change between the use of an entrance slit and a slitless operation mode as well as a maximum compactness and robustness due to a reduced number of motorized stages. Characterization measurements as well as first proof-of-principle X-ray emission investigations show the potential of the instrument for versatile applications.A flexible spectrograph for the investigation of soft X-ray spectra in the range between 1 nm and 20 nm is presented. Based on two variable-line spaced reflection gratings, the design enables stand-alone operation, the change between the use of an entrance slit and a slitless operation mode as well as a maximum compactness and robustness due to a reduced number of motorized stages. Characterization measurements as well as first proof-of-principle X-ray emission investigations show the potential of the instrument for versatile applications.

Identifications of the plasma boundary shape and mode structure are important problems for the studies of the magnetohydrodynamics equilibrium and stability studies. Imaging diagnostics have the possibility to measure the plasma boundary shape and mode structure directly. The soft X-ray (SX) tomography is an imaging diagnostic for offering these direct measurements. However, SX tomography is by nature a limited angle tomography and provides a challenge as an ill-condition inverse problem. The reconstructed profiles depend heavily on the quality of measurements along with the employed inversion algorithm. This paper provides a detailed description of tomographic reconstruction of simulated SX measurements from the current SX diagnostic design of Heliotron J (H-J), which is a medium size heliotron device. Heliotron J has a unique magnetic geometry, and the quantitative identification of the plasma boundary and mode structure is a critical problem. The Phillip-Tikhonov regularization is employed to address the inversion problem. Finally, a new design for Heliotron J soft X-ray diagnostic is discussed which holds enhanced capabilities for tomographic reconstructions especially for the high poloidal number perturbations.

BACH, a soft x-ray beamline for polarization-dependent experiments at the Italian synchrotron radiation facility ELETTRA, was recently completed and characterized. Its performance, in terms of energy resolution, flux and polarization, is presented. Based on two APPLE II undulators, BACH covers the energy range between 35 and 1600 eV with the control of the light polarization. The monochromator is equipped with four gratings and allows one to work either in a high resolution or in a high flux mode. After the monochromator, the beamline is split into two branches with different refocusing properties. One is optimized to exploit the performance of the soft x-ray spectrometer (ComIXS) available at the beamline. Resolving powers between 12000 at 90 eV photon energy and 6600 near 867 eV were achieved using the high-resolution gratings and the smallest available slit width (10 μm). For the high-brilliance grating, which works between 290 and 1600 eV, resolving powers between 7000 at 400 eV and 2200 at 867 eV wer...

A high-speed tangentially viewing soft x-ray camera system has been developed and installed on the large helical device (LHD) using a video camera with a maximum framing rate of 13.5 kHz. Low-frequency activities, for example, structures with toroidal/poloidal mode number n/m = 1/2, are directly detected with this system.

Soft x-ray (SX) detector array systems are installed on the Large Helical Device (LHD). Two types of systems are in operation: An 80 ch array for detailed profile measurement and two sets of 40 ch array installed inside the vacuum vessel suitable for fluctuation studies. Recent results of the profile and fluctuation measurement with this system are discussed.

A high-speed image converting system is described. The system is capable of display both in multiframing- and streak-mode image for a pulsed x-ray source. The system relies on a new concept without employing an image converter tube. To achieve both temporally and spatially resolved display, the image of the x-ray source is acquired with a pinhole camera and with multichannel arrayed scintillator–photomultiplier combinations, which are used complementarily. The temporal resolution is 3 ns. This system is successfully used to observe the time evolution of soft x-ray emissions around 4 A in plasma focus discharges with puffed Ar.

We describe a new liquid-target system for low-debris laser-plasma soft x-ray sources. The system is based on a microscopic liquid jet and is experimentally evaluated for 0.7-1 keV proximity lithography and water-window x-ray microscopy applications. Compared to an existing liquid-droplet target, this target system has the same low debris emission, high x-ray photon flux, and narrow spectral bandwidth. The advantages of the liquid-jet target include improved x-ray flux stability, increased range of suitable target liquids, and elimination of the need for temporal synchronization, thereby allowing less complex laser systems to be used. (C) 1996 American Institute of Physics.

The authors have developed a control method of spatial film thickness distribution of multilayer mirrors for soft‐x‐ray focusing systems using an argon–fluoride (ArF) excimer laser‐induced chemical vapor deposition (LCVD). A line‐shaped laser beam is unidirectionally scanned over an area of 100×100 mm2. The scanning speed is controlled in response to a film thickness distribution which is required to be obtained. A tungsten–silicon (W/Si) multilayer with laterally varying film thickness is successfully fabricated on the design rule, and soft‐x‐ray (λ=12.8 nm; not polarized) reflectivities from 37% to 20% are obtained at the grazing angles from 18° to 22° in response to the film thickness distribution. Furthermore, the amount of the soft x rays reflected by the multilayer within 100 mm of the substrate is estimated at about 90% of that in the case of the designed distribution, and the feasibility of LCVD for fabricating multilayer mirrors for high performance soft‐x‐ray focusing systems has been demonstrated.

Soft x-ray emission from laser irradiated gold foils was measured at the Omega-60 laser system using the Dante photodiode array. The foils were heated with 2 kJ, 6 ns laser pulses and foil thicknesses were varied between 0.5, 1.0, and 2.0 μm. Initial Dante analysis indicates peak emission temperatures of roughly 100 eV and 80 eV for the 0.5 μm and 1.0 μm thick foils, respectively, with little measurable emission from the 2.0 μm foils.

This paper describes a new 500 MHz cavity which has a simple damped structure for the 2.0 GeV high‐brilliant synchrotron radiation source. The damping of higher‐order modes (HOMs) is achieved by large hole beam ducts, a part of which is made of microwave absorber. We have adopted as the microwave absorber a sintered SiC named CERASIC‐B manufactured by Toshiba Ceramics Co. Ltd. The latest design of the cavity with CERASIC‐B beam ducts is presented in this paper. We have fabricated a prototype model of the cavity. The results of the low power measurement are also reported here. It was confirmed that by using the CERASIC‐B beam ducts the Q values of HOMs were strongly damped.

A high precision five rotation-axes polarimeter using transmission multilayers as polarizers and reflection multilayers as analyzers has been designed and manufactured. To cover the extreme ultraviolet regime, Mo/Si, Cr/C, Sc/Cr, and W/B4C multilayers for transmission and reflection have also been designed and produced. The polarimeter mechanics is supported on a hexapod to simplify the alignment relative to photon beam. The instrument is designed so that it can be easily transferred between different beamlines.

A simple valid in situ relative intensity calibration technique for soft x‐ray film is described. This is based on film exposure measurements of the uniform line‐shaped distributed soft x‐ray monochromatic irradiation transmitted through a step‐wedge absorption filter. Fitting the calibration data with Henke’s semiempirical equation for thick‐emulsion film, the characteristic curves for Shanghai 5F soft x‐ray film without supercoat (SIOM‐5FW) have been obtained in the wavelength region from 50 to 80 A.

A tangentially viewing soft x-ray camera system is to be installed on the Large Helical Device (LHD). This camera system is aimed at exploring both detailed structures of the magnetic surfaces of the LHD plasma and helical islands induced either due to magnetic field errors or MHD instabilities. The frequency range this system is capable of exploring is 0

A complete polarization analysis has been successfully achieved for synchrotron radiation beams in the vacuum ultraviolet and soft x‐ray regions using a reflection polarimeter. The Stokes parameters, which provide a full description of the polarization state of light, were experimentally determined along with three polarizing quantities of the polarimeter. The present result indicates the possibility of a simultaneous determination of the optical constants of mirror materials through polarization analyses.

A plane‐grating monochromator (PGM), the CAMD‐PGM, designed for bending magnet radiation is described. In contrast with many other similar PGMs, the CAMD‐PGM is equipped with an entrance slit. The wavelength range of 6–1500 A is covered with two gratings (1220 and 360 gr/mm). The expected performance is a resolving power, λ/Δλ, of ∼2000 with the photon flux of ∼ 1010 photons/s at the photon wavelength of 10.0 A. The beam spot size at the sample position is approximately 1×1 mm2. The monochromator is being constructed and will be installed in the summer of 1992.

We complemented with data taken in transmission mode the recently described tests of the novel spectromicroscope MEPHISTO (Microscope a Emission de Photoelectrons par Illumination Synchrotronique de type Onduleur). Transmitted x rays were converted by a photocathode into photoelectrons, which were subsequently electron-optically processed by the spectromicroscope producing submicron-resolution images. Test images demonstrated excellent contrast. (C) 1998 American Institute of Physics. [S0034-6748(98)02409-5]

Line scans of micro‐ to submicron‐width stripe patterns with soft x‐ray (150 eV) microbeams formed by Wolter‐type mirrors were performed by detecting total photoelectron intensity. The samples were aluminum stripes delineated on a SiO2 wafer with identical width and spacing of either 0.7, 1, or 4 μm. The modulation of an image of the 4‐μm‐linewidth stripe pattern, which was obtained by scanning a 2.1 μm focused beam, was 0.33. The modulations of images for the 1‐μm‐linewidth stripe pattern and for the 0.7‐μm‐linewidth stripe pattern, both of which images were obtained by scanning a 1.8 μm focused beam, were, respectively, 0.12 and 0.08. We achieved the highest lateral resolution in one‐dimensional photoelectron imaging performed by grazing incidence mirrors.

A tunable polarimeter using multilayer interference coatings as both reflection polarizer and transmission phase retarder is described. The portable device bolts onto existing chambers and its rotation axis is precisely aligned to the beam. The upstream transmission phase retarder is tunable by varying its incidence angle, and the downstream polarizer is tunable by translating a laterally graded multilayer. These optical components allow an unambiguous determination of the polarization state of any collimated beam entering the device over at least the 50–800 eV range.

In the soft x‐ray region below 3 keV, various electron yield (EY) techniques have been employed in x‐ray absorption fine structure (XAFS) measurements of bulk materials. The fluorescent x‐ray yield (FY) is also utilized for samples of low concentration. Although FY becomes much smaller for lighter elements, it has several advantages compared with EY to measure XAFS spectra; for example, a higher signal‐to‐background ratio and applicability to insulating materials. However, it has been thought to be unsuitable for concentrated samples due to a self‐absorption effect. In this report, the sampling depth and self‐absorption effect for bulk concentrated samples are discussed concerning XAFS measurements in a few keV energy region. Some typical FY XAFS spectra of concentrated materials, including insulators, are presented.

At the radiometry laboratory of the Physikalisch‐Technische Bundesanstalt (PTB) a reflectometer for the soft x‐ray spectral region has been operated for several years utilizing monochromatic radiation of a toroidal grating monochromator or a high‐resolution plane grating monochromator. The monochromators cover the photon energy region from 35 to 1500 eV. New challenges due to the development of soft x‐ray optical components led to the design of a second reflectometer with advanced capabilities. Samples with a diameter of up to 250 mm can be accommodated. The time required for sample exchange is reduced by using a lock chamber. The feasibility of sample positioning with high precision has been improved. Typical uncertainties of about 1%–2%, e.g., for the reflectance of multilayer mirrors, can be achieved. A detailed description of the reflectometer as well as some typical results showing the performance are presented.

A soft x‐ray emission spectrometer equipped with a multilayer rotating analyzer has been made. The spectrometer covers an energy range of 50–500 eV with a resolution power of about 300. Using the rotating analyzer we have measured the polarization of the B K emission of h‐BN, and have found that it is dominantly polarized perpendicularly to the c‐axis, which agrees well with the experimental result.

Previous magnetic field measurements on the entrance half of the NIST undulator showed errors that resulted in a beam path deflection of 5.2 mm [Wallace et al., Nucl. Instrum. Methods A 331, 759 (1993)]. Pole height variations as much as .009’’ gave rise to field errors of up to 2% at a gap of 20 mm. We report on our effort to rebuild the NIST undulator through a series of in‐situ and off‐line measurements and modifications. Initial results indicate that at 40 A, a brightness of 2.5×1018 (ph/sec/mm2/mrad2/A/0.1% BW) can be achieved. Commissioning of the undulator will take place in January 1996.

For the first time, the spectral responsivity of the same silicon n on p photodiode has been determined with self‐calibration techniques in the visible and soft x‐ray regions. Together with results from other calibrations the spectral responsivity is presented for the whole photon energy range from 1.2 eV to 3 keV.

A universal polarimeter was designed and built to analyze polarization properties of soft x‐ray and vacuum ultraviolet radiation from different types of sources. The design, based on the use of multilayer‐polarizers, includes an option to monitor the polarization with a 1 kHz frequency. The polarimeter was tested on the U5 undulator beamline at NSLS.

The development of soft x‐ray mirrors and large aperture soft x‐ray beamsplitters now allows the near routine operation of soft x‐ray interferometers with high brightness x‐ray sources. Mach‐Zehnder and Fourier transform interferometers utilizing a soft x‐ray laser light source operating at 80 eV will be described. Results from high density, long scale‐length plasma probing measurements, x‐ray laser coherence measurements, and materials properties measurements will be presented.

The Zeff profiles from the tangential array of visible bremsstrahlung (VB) emission (5235 A) have shown several interesting features in TFTR. The observed Zeff profile was flat during the ohmic phase and hollow during the neutral‐beam heating phase. In order to crosscheck the measured Zeff profiles from the VB array, a poloidal array which measures bremsstrahlung emission in the soft x‐ray region has been analyzed. The analysis of array measurements in the two different spectral regions was performed on the same geometry determined from the Abel inversion of the electron density (interferometry). The two independent measurements of Zeff profiles have been consistent with each other for most of the discharges in TFTR. However, in a discharge where the two measurements are inconsistent, the Zeff profile deduced from the VB array indicates some degree of problems. In this paper, the detailed analysis of the bremsstrahlung array (both poloidal and tangential) measurements is presented. Particularly, the effec...

We report on the performance of a newly constructed synchrotron radiation soft x‐ray beamline. This beamline, dubbed Dragon, is a spherical version of the cylindrical element monochromator design proposed previously. By measuring the K‐edge absorption spectra of condensed nitrogen, it is determined that this monochromator has achieved resolving power 104 at 400‐eV photon energy, using its full 15 by 1 mrad angular acceptance. The ideas and advantages contained in the CEM design have also been experimentally confirmed.

The optical layout of a novel soft x‐ray beamline at the Daresbury Synchrotron Radiation Source (SRS) is presented, together with the mechanical design of a precision‐built soft x ray crystal monochromator. The mechanical and optical performance of the system are discussed, supported by data on the output flux and resolution of the monochromator. The flexibility of this optical arrangement for different kinds of experiments is examined.

A set of fine‐focusing soft x‐ray sources has been manufactured to meet the requirements of research and development work at the BEPC Synchrotron Radiation Laboratory. The electrical and optical characteristics of the source as well as preliminary experiments on contact microscopy performed with the source are reported.

Soft x‐rays (2 to 6 keV) have been observed from transition radiators using electrons at energies of 104 and 66 MeV. The observed spectra agree well with theory. Various stacks of mylar of 2.5, 3.5 and 6.35 μm thickness were used to produce the radiation. Optimum foil thicknesses and number were calculated and found experimentally to be correct.

An x‐ray spectrometer based on the Johann bent‐crystal principle is described. An entrance slit system has been adopted which provides excellent protection of the diffracting crystal from metallic vapors. Such an arrangement also provides improved resolution and dispenses with the need for a thin film window between the x‐ray source and spectrometer tank. Resolution comparable to a two plane‐crystal instrument has been attained and systematic studies of the soft x‐ray emissions from liquid metals and alloys and metallic vapors undertaken.

Novel microstructures manufactured with high precision and reproducibility are proposed for high‐resolution collimators in flat crystal soft x‐ray monochromators for plasma spectroscopy. The newly developed technique for this type of collimator is based on surface structuring of foils using profiled microdiamonds. Results of x‐ray tests of a microstructure collimator demonstrate that the predicted angular resolution of 5000 at a transmission of about 0.3 can be obtained.

An apparatus dedicated to characterizing the VUV and soft x‐ray optical elements was fabricated, and a preliminary test on its performance was made in the soft x‐ray region with a grasshopper monochromator at the Photon Factory. The results demonstrated that quantitative evaluation of diffraction efficiency of a grating could be easily performed using the apparatus.

Lexan coatings on polypropylene windows can eliminate the UV sensitivity of soft x-ray proportional counters. A method is described for coating thin polypropylene films by dipping into and withdrawing from a volatile solution containing Lexan. The x-ray absorption of a typical Lexan coating was only 7% at 44 A which is small compared to that of 2 microm of polypropylene. The Lexan coatings are stable against vacuum cycling in an environment of UV irradiation. As an external, far-UV filter up to wavelengths of 2400 A, Lexan-coated polypropylene is an interesting alternative to metallic films, particularly when large area, high x-ray transmission, and strength are important.

It is demonstrated in this note that optical Polaroid Land films can be used as a convenient detector in the soft x‐ray region. The performance of Polaroid 667 film has been found to be comparable to that of the Kodak direct exposure film (DEF) for soft x‐ray pinhole imaging. By a suitable choice of multiple filters, qualitative information about a dense plasma has been obtained.

A VUV/soft x‐ray monochromator was developed for utilizing undulator radiation from a 26‐period multipole wiggler/undulator at the Photon Factory. An entrance slitless quasi‐Rowland circle mounting was adopted to the monochromator optics, aimed at achieving the compatibility of high resolution with high‐output flux. The optics was realized by a decoupling of horizontal focusing with a deflection mirror from vertical focusing with an aberration‐free vertical dispersion system which was composed of a cylindrical mirror and a concave grating. The optics and mechanism of the monochromator as well as its test operation made after installation are described.

The construction of a simple and versatile soft x‐ray appearance potential spectrometer is described. The soft x rays are detected by measuring the positive current produced by photoemission from a stainless steel photocathode, which enables the detector circuit to be near ground potential and permits operation under pressures greater than 10−7 Torr. Typical operating conditions are described.

Multiple element soft X-ray source for study of soft X-ray region of electromagnetic spectrum, obtaining absolute photon yield of carbon K and boron K

Photoconductivity in certain selected single crystals of CdS, by comparison with conventional Geiger‐type counters, affords a fairly sensitive and inexpensive detector for simple x‐ray spectrometry.

A 4‐keV soft x ray is measured using a microchannel plate (MCP) and a visible light multichannel analyzer. A transparent photocathode is mounted in close contact with the front surface of the MCP to compensate for the reduction in gain of the obliquely incident soft x ray. Favorable improvement in sensitivity was obtained even at a large incident angle without reduction in the resolving power.

An alternative method of measuring soft x‐ray appearance potential spectra is presented. In this method no modulation, tuned tank, or lock‐in amplifier are used. Rather, the dc current induced in a simple Park‐Houston type detector is measured and digitized, and the data are placed on paper tape for computer processing and differentiation. The computer differentiated spectra compare favorably with spectra obtained by modulation technique.

The spectrometer described is a grazing incidence grating instrument with an improved drive system for moving the electronic detector around the Rowland circle. In this system the lead screw driving the detector always lies along a chord of the Rowland circle joining the grating and the detector. With this design there is less chance of error due to flexure of the components than in previous designs, and the resolution of the spectrometer is constant in wavelength.

A method is described which improves the signal‐to‐noise ratio in soft x‐ray appearance potential spectroscopy (SXAPS). The incoming photon beam is filtered ahead of the detector by means of thin metallic foils or organic films, resulting in reduction of very low energy photons which produce unwanted noise in the detector. A specific example is given of the use of a 6.3 μ aluminum foil filter in the study of samarium M spectra.

A demountable x‐ray source capable of operation up to 3 kW is described. Construction is largely of stainless steel with elastomer seals. The source is of use in exciting secondary spectra and producing bremsstrahlung for absorption studies.