Plane-grating Monochromator Research Articles

Design of soft x-ray plane-grating monochromator for CAMD

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 Å 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 Å. 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.

XUV laminar holographic gratings: Compared performances for monochromator, spectrograph and conical-diffraction configurations

We compare the performances of various types of XUV spectrometers in terms of grating efficiency and spectral resolution: toroidal grating monochromator (TGM) and spectrograph (TGS) on one hand and plane grating monochromator (PGM) on the other. From both points of view, TGSs are able to work over wider spectral ranges than TGMs, particularly for large deviation angles and groove densities. PGMs allow better aberration correction and resolution than TGM configurations.

Optical design of a 200 eV–2.5 keV cylindrical element monochromator for the 1.3-GeV storage ring of SRRC

Separate focus-function mirrors in combination with a simple-scanning spherical/cylindrical grating are to be used for an extreme grazing-incidence beamline design in the photon energy range of 200 eV–2.5 keV at the ARC synchrotron radiation of the TBA lattice of SRRC. Three mechanically ruled gratings are used to cover the spectral wavelength range of the extreme VUV and soft x rays. Both the throughput and the resolution of this optical system have been carefully calculated and compromised against the grazing angle, arm length, grating size, etc. The proper parameters of the optical elements as well as their geometrical arrangements are proposed. A resolving power of at least 2000 is obtainable at the high-energy end of the spectrum around 2 keV. At the low-energy end, the resolving power can be as high as 8000, comparable to a grazing-incidence Rowland circle type of monochromator. The overall resolving power has been found to be superior to that of either the plane grating monochromator (PGM) or the 10-m toroidal grazing monochromator (TGM) in the same spectral wavelength range.

A plane-grating monochromator for radiometric calibration

A new plane-grating monochromator and calibration chamber were constructed for the radiometric calibration of plasma diagnostic devices. The monochromator is designed to cover a wavelength range of 1.8–238 nm with moderate resolving power of 500±200 in λ/Δλ. To check the performance of the monochromator, spectral distribution and resolution were measured by experiments on photoemission from solids and photoionization of rare gases. The characterization of multilayer reflectors by the use of this beamline is demonstrated.

Development of a grazing incidence ultrasoft x-ray monochromator for radiation biology studies (abstract)

Irradiation experiments on biological samples with monochromatic ultrasoft x-rays are inevitable in elucidating the initial process in radiobiological phenomena. However, intense light sources with continuous spectra in this wavelength region have not been available until recently. Synchrotron radiation is the best light source for the study because of its intense, continuous emission spectrum. The purpose of the project is to develop a grazing incidence ultrasoft x-ray monochromator for radiation biology studies using synchrotron radiation as a light source. The following characteristics are required in the monochromator, namely, (1) high throughput with moderate resolution; (2) wide beam area with uniform intensity; (3) little contamination of higher order lights; and (4) easy operation and maintenance. Considering the above requirements, a plane-grating type monochromator (PGM) is adopted. The monochromator consists of two premirrors (M1 and M2), a plane grating (1200 ℓ/mm), a concave focusing mirror (r=12 m) and an exit slit. Two premirrors with different incident angles can be used interchangeably to eliminate higher order lights in the desired wavelength region. Wavelength of 30–70 A is available when M1 is used and 80–250 A when M2 is used. Expected wavelength resolution is 1% when the width of exit slit is 300 μm. All vacuum chambers accommodating these optical elements are bakable in order to attain ultrahigh vacuum. Wavelength is controlled by a microcomputer system equipped with a stepping motor and an encoder. This monochromator will be installed at beamline 12C at the Photon Factory, National Laboratory for High Energy Physics, and will be open to outside users in radiation biology by the end of 1988.

The high energy plane grating monochromators at BESSY

Two plane grating grazing incidence monochromators based on the author's solution of the plane grating focussing term are described. The instruments continuously cover the soft X-ray spectral range up to 2 keV. Source size limited spectral resolution can be obtained when the influence of the too high tangent error of the present focussing mirror is eliminated through aperture reduction. Higher orders can be suppressed by varying the cutoff angle at the plane premirror. The stray light content of the spectrum is very low and allows an edge-jump of 1:2.5 at the silicon K-edge.

A soft X-ray monochromator for the MAX synchrotron radiation facility

A high resolution soft X-ray monochromator for the 550 MeV MAX storage ring is described. The instrument combines a plane elliptical premirror collecting a large (10 mrad) horizontal angle of radiation and a modified version of the well-known SX-700 plane grating monochromator (PGM). The modification consists of changing the original ellipsoidal focussing mirror to a plane elliptical mirror. Thereby the horizontal and vertical focussing are decoupled and good imaging properties are obtained irrespective of the large horizontal acceptance angle. The MAX-PGM will be part of an experimental station for photoelectron, photoabsorption and photon stimulated ion desorption spectroscopy.

A plane-grating monochromator for 2 eV ≤ hv ≤ 150 eV

Design and performance of a plane-grating monochromator at UVSOR facility are described. Two monochromators of the present design have been constructed and are used for optical and photoelectron spectroscopy of solids.

Performance of a new plane-grating grazing-incidence UHV monochromator

A UHV monochromator with an ion-beam etched plane laminar grating (1200 grooves/mm) is designed, constructed and installed at the third beam line of SOR-RING (a 0.38 GeV electron storage ring). By using four interchangeable pre-reflecting plane mirrors (incidence angles set to 88, 75, 70 and 35°, coated with gold or aluminum) and two interchangeable spherical focusing mirrors (88 and 83°), one can cover the photon energy region from 8 to 400 eV with low content of the higher order light and the stray light. The performance of this monochromator is checked by reflectance, photoemission and photoelectron diffraction experiments.

Higher-order suppression in an on-blaze plane-grating monochromator

The transmittance of an on-blaze plane-grating monochromator has been calculated as a function of wavelength for different spectral orders. The calculations show that higher, undesirable orders can be suppressed by a judicious selection of grating blaze angle and coating material. However, for intense sources, such as a storage ring operating at high power and current, higher-order suppression due to blaze angle and coating material may have to be augmented by using transmitting filters or spectrally selective detectors or both.

Carbon KVV Auger spectroscopy using a plane-grating monochromator at the National Synchrotron Light Source

We report on our first adsorption studies using a plane-grating monochromator (PGM) at the National Synchrotron Light source (NSLS) at Brookhaven. This is one of several new beam lines providing access to the photon energy region around and above the carbon K-edge (∼285 eV). Specifically we report observations of the Carbon KVV Auger contribution to the photoemission energy spectra for CO adsorbed on Pd(111) on passing through the resonance for excitation of C 1s electrons into the unoccupied 2π∗ bound state of the CO molecule. The results show no conspicuous evidence for the recently proposed enhancement mechanism involving 2π∗ spectator electrons. The effectiveness of core-hole screening can be estimated by comparison with inverse photoemission observations of the 2π∗ orbital.

The national synchrotron light source VUV and soft x-ray beam lines: Performance characteristics

A total of five beam lines are currently being constructed and commissioned at the NSLS. They involve a 2.75° toroidal grating monochromator, a plane grating grazing monochromator, a large aperture modified Wadsworth monochromator, a Seya-Namioka instrument and a Czerny-Turner instrument. We present details of these beam lines and their anticipated operational characteristics.

Plane grating monochromators for synchrotron radiation

The general background and theoretical basis of plane grating monochromators (PGMs) is reviewed and the particular case of grazing incidence PGMs suitable for use with synchrotron radiation is considered in detail. The theory of reflection filtering is described and the problem of the finite source distance is shown to be of special importance with high brightness storage rings. The design philosophy of previous instruments is discussed and a new scheme proposed, aimed at dealing with the problem of the context of Wolter-type telescopes and microscopes. Some practical details concerning an instrument presently under construction using the new design are presented.

Direct Measurement of Optical Transfer Functions of Spectroscopic Systems

A light source emitting the radiation of sinusoidal spectra was prepared using a Fabry-Perot interferometer. Measuring the responses of the sinusoidal spectra of this light source, the optical transfer function (O.T.F.) of a plane-grating monochromator was determined. A blurred spectrum of the Na–D doublet was corrected by means of this O.T.F. The profile thus corrected was better than those corrected by the O.T.F.s determined from the Fourier transforms of line profiles.

Aberrations of Plane Grating Monochromators with Off-axis Paraboloidal Mirrors

Aberrations of plane grating monochromators with off-axis paraboloidal mirrors are studied analytically by the use of the light-path function and the Burch plate diagram extended to off-axis systems. Residual wave aberration of the third order becomes vanishingly small by compensation of two aberration terms in the U configuration, but remains fairly large by accumulation in the Z configuration. This explains an excellent image quality of the U configuration. It is shown that exact slit-image-curvature invariance with wavelength exists in the Z configuration but does not in the U configuration. A suitable value of the distance between the grating and off-axis paraboloidal mirror can be determined to eliminate certain residual aberration terms of the fourth order.

Correction of a Spectral Image Formed by a Plane-Grating Monochromator by Means of Optical Transfer Functions–A Partially Coherent Case

Optical transfer functions (O.T.F.'s) of a simple plane-grating monochromator were determined by both of experimental and theoretical methods in case of partially coherent image formation. Because of low degree of coherence, the light intensity was regarded to be additive as in the case of incoherent image formation. In an observed spectrogram of Hg 6P–6D lines, the faint shoulder corresponding to the weak 578.97 nm line appeared clearly when it was corrected by means of the O.T.F.'s.

Correction of a Spectral Image Formed Incoherently by a Plane-Grating Monochromator by Means of Optical Transfer Functions

Correction of a Spectral Image Formed Incoherently by a Plane-Grating Monochromator by Means of Optical Transfer Functions

Correction of Spectra Formed by a Plane-Grating Monochromator by Means of Optical Transfer Functions

Optical transfer functions (O.T.F.'s) for the correction of spectral images formed by a simple plane-grating monochromator were determined by both of theoretical and experimental procedures ; the ray-tracing method and a spectrogram of monochromatic rays were respectively used to determine line spread functions, and their Fourier transforms gave the the O. T. F.s. A spectrogram of the Na D-doublet poorly resolved was satisfactorily corrected by means of the both O. T. F.'s.

平面回折格子モノクロメータのO.T.F.と像修整(III)

平面回折格子モノクロメータのO.T.F.と像修整(III)

Beam-foil spectroscopy with low-energy accelerators

A discussion is given of the problems associated with the measurement, by the beam-foil technique, of the mean lives of excited states of ions. The case in which the transition of interest is isolated using a plane-grating monochromator is considered in detail and the optimum mode of use determined. Results are presented which show that the plural scattering of the ions in the exciter-foil sets a limit to the wavelength resolving-power attainable.