JPH0354424B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention generally relates to an apparatus for irradiating an object with X-rays in a normal environment, such as atmospheric air.

The device according to the invention is suitable for applications where it is expensive, time consuming, or inconvenient to move objects to be irradiated with soft X-rays into and out of special environments such as vacuum chambers that generate X-rays. Particularly useful. Typical applications for this type of equipment include high-resolution lithography, extended X-ray absorption fine
This includes laser-based X-ray equipment for spectroscopy and X-ray microscopy of structures (EXAFS).

Although X-rays are generally produced in a vacuum, in many applications it is desirable to use them in air. However, windows made thick and strong enough to withstand the pressure difference between vacuum and air are opaque to soft X-rays, especially those with photon energies below about 5 KeV. Extracting X-rays from a vacuum into air is problematic (unless the window is made very small and thin). To solve this problem, it is desirable to irradiate a large area.
This is particularly serious in the case of line lithography.

The present invention overcomes this problem in a simple, inexpensive and
and provides a convenient device.

U.S. Pat. No. 4,058,486 shows that an intense point source of X-rays can be created by focusing a solid-state target laser beam. A neodyum laser beam focused on a solid slab target was converted into tens of joules of X-rays emitted from an essentially point source (about 100 microns in diameter) within a nanosecond with an efficiency of more than 25 percent. . The pattern of x-rays produced by a steel target irradiated with a laser pulse of about 100 joules at an angle of incidence of about 45 degrees is generally non-directional. Conversion efficiency of more than 25% is radiated from the slab 2000
3000 angstrom plastic coated with angstrom aluminum
corresponds to X-rays passing perpendicularly through the paraline. This conversion efficiency is thus a lower limit, and only corresponds to the portion of the spectrum above about 300 electron volts.
Most of the observed X-rays are between about 0.3 and 15 KeV, with a small but useful fraction reaching 10 to 100 KeV. When the refractive crystal spectroscopy results obtained from the KAP crystal were examined with a densitometer,
The radiation has a spectral spacing of approximately
It appears to be between 0.7 and 1.2 KeV. The unusual sharpness in the spectral details is due to the small size of the point source. This novel point source of X-rays provides a tunable spectrum in the range of about 0.1 to 100 KeV.

The apparatus according to the invention is typically of the type described above.
A line generator is used. However, the device may also use other somewhat similar devices, such as devices that use electron beams other than laser beams, to generate the x-rays.

A typical apparatus according to the present invention for irradiating x-rays onto an object in a normal environment, such as air, at approximately atmospheric pressure, is capable of applying x-rays to a target in order to generate x-rays of a selected spectrum and intensity at the target. a means for directing energy to the target; a first sealed chamber generally fluid-tight about the target; and reducing the amount of gas therein to maintain the pressure within the first sealed chamber at generally below atmospheric pressure. and a second sealed chamber adjacent to the first sealed chamber that is generally fluid-tight and contains a gas highly transparent to X-rays to the general exclusion of other gases;
One wall of the first sealed chamber is large enough to allow the X-rays to pass through it, but the decompressor can reach them as quickly as they enter through it at the required pressure. an aperture small enough to allow gas to escape from the first sealed chamber, the target directing a substantial portion of the generated x-rays toward the aperture;
positioned sufficiently close to the aperture to pass through the aperture, the first wall of the second sealed chamber being highly sensitive to x-rays positioned adjacent to the aperture in the wall of the first sealed chamber. a transparent portion, such that X-rays passing through the opening proceed through the transparent portion toward a separate second wall in the second sealed chamber;
the gas in the sealed chamber is maintained at a pressure approximately equal to atmospheric pressure at least near the second wall, and
This second wall is provided with a portion that is highly transparent to X-rays, thereby allowing an object such as a patient to be placed adjacent to the X-ray transparent portion of the second wall outside the second sealed chamber. It is designed to be able to irradiate X-rays that are not attenuated by air or the like while the device is placed in the same position.

The device also has a generally fluid-tight intermediate chamber adjacent to the first enclosure, the intermediate chamber having an interior wall that partially shares a portion of the wall of the first enclosure with the opening; an outer wall substantially parallel to the common wall and having an opening in the common wall and an opening aligned between and aligned with the X-ray transparent portion of the first wall of the second sealed chamber; through them to the second wall of the second sealed chamber, further reducing the amount of gas in the intermediate chamber and maintaining the gas pressure at a value between the pressures in the first and second sealed chambers. The opening in the outer wall is small so that the pressure reducing means is capable of displacing the gas in the intermediate chamber at least at the velocity of the gas entering through the opening.

The device also has at least one additional similar intermediate chamber between the first and second sealed chambers, the adjacent intermediate chambers being positioned on opposite sides of a common wall provided with openings, and wherein all of the openings thereof is positioned between and aligned with the opening in the wall of the first sealed chamber and the permeable portion of the first wall of the second sealed chamber, the apparatus further reducing the amount of gas in each additional intermediate chamber to means for maintaining the pressure at a value intermediate between the pressures in adjacent closed chambers, the opening in each chamber being small so that the means for reducing the pressure in each intermediate chamber will reduce the pressure within the intermediate chamber at least at the velocity of the gas entering through that opening; It is designed to allow gas to escape.

The pressure within each intermediate chamber is typically maintained logarithmically at approximately midway between the pressure values of the chambers on either side of it. The spacing between parallel walls should be large enough to avoid gas flow between them. Typically, the spacing between the outer and outer (parallel) walls of the first intermediate chamber is approximately 2 to 10 mm;
The distance between the parallel walls of the next intermediate chamber is approximately 0.5 to 5 mm.
Furthermore, the distance between the parallel walls of the next intermediate chamber is approximately 0.1 to 2.
Let it be millimeter. The aperture allows the X-rays passing through it to
Size it to form a cone with a 10 degree apex angle.

In an exemplary embodiment of the invention, the second sealed chamber is formed by a lightweight gas drift tube. Typical gases within the tube include helium, hydrogen, and hydrocarbons, preferably helium, at about atmospheric pressure. The distance from the first wall to the second wall in a typical trift tube is about 0.5 to 5 meters. the first in the drift tube;
The radiolucent portion of the wall and the radiolucent portion of the second wall typically consist of a thin foil (typically consisting essentially of beryllium or a low valence (low L) plastic material). foil). The thickness of the foil is typically about 2 to 20 microns.

In a typical embodiment of the present invention, an opening is provided in the X-ray transparent portion of the second wall of the second sealed chamber, and a gas having high X-ray transparency is supplied to the second sealed chamber. Provide means. The opening in the X-ray transparent part is made small so that the gas supply means supplies the X-ray transparent gas to the second sealed chamber at least at the rate of the gas being exhausted through the opening, and the other gas is Entry into the second sealed chamber can be substantially prevented.

The gas conveyed to the second enclosure is typically helium, hydrogen, or a hydrocarbon, preferably helium, at a pressure of about 0.9 to 1 atmosphere at least near the permeable portion of the second wall. is maintained. The permeable portion of the second wall of the second seal comprises a foil, typically consisting essentially of beryllium or a low valence plastic material. The thickness of the foil is typically about 2 to 20 microns.

Since the gas in the second sealed chamber, at least near the X-ray transparent portion of the second wall of the sealed chamber, is maintained at approximately atmospheric pressure, an opening may be provided in the transparent portion, and The gas inside said second closed chamber is controlled by a gas curtain passing through said opening, or by an object to be subjected to X-rays, or by being placed against said wall and covering said opening. can be substantially separated from the surrounding air by elements attached to said object.

The device according to the invention for taking EXAFS data of a material receives the X-rays passing through the aperture and directs the spectrally resolved X-rays towards an X-ray transparent part adjacent to the object to be irradiated with the X-rays. Typically, the second sealed chamber includes a disposed spectrum spreading means, and the object includes a recording means. The device also typically takes a sample of the material within the second sealed chamber or outside the second sealed chamber between the X-ray transparent portion of the second wall and the recording means. It also includes means for positioning in the optical path of the x-rays.

The means for directing the energy includes means for directing the energy from the laser beam to a point on the target having a diameter of, for example, about 1 to 200 microns. The aperture in the common wall portion is typically about 0.2 to 2 mm in diameter, and the distance between the aperture and a point on the target is about 0.2 to 5 cm. The x-rays produced by the target typically have an energy of approximately 0.3 to 2 KeV.

Now, as shown in the drawings, particularly in FIG. means, such as a lens 13, for directing the energy 14 to its target 15 to produce X-rays 11 having an intensity of 1 closed room 16
The gas inside is discharged in the direction of arrow 17 until the pressure inside is approximately below atmospheric pressure (typically below about 1 Torr).
(such as a vacuum pump, not shown)
A second sealed chamber 18 adjoining the first sealed chamber 16 contains a gas 24 which is substantially fluid-tight and highly transparent to X-rays.
The walls 19 of the first sealed chamber 16 are large enough to allow the X-rays 11 to pass therethrough, but the pressure reduction means are at least as fast as the gas passes therethrough. The target 15 has an aperture 20 small enough to allow gas 21 to be evacuated from the aperture 20, and the target 15 is sufficiently close to the aperture 20 to emit a significant portion of the generated X-rays 11 toward and through the aperture 20. and is positioned. A wall 35 provided within the second closed chamber has a portion 20' (FIG. 1) or 36 (FIG. 3) positioned close to the opening 20 and highly transparent to the X-rays 11; The X-rays passing through 20 reach the same parts 20', 3
6 and toward the opposite wall 22 of the second sealed chamber 18. The wall 22 has a portion 25 that is highly transparent to X-rays, through which the X-rays 11 illuminate an object 12 positioned adjacent to the portion 25 outside the second sealed chamber. It is becoming more and more common. Therefore, the X-rays irradiated to the object are hardly attenuated by air or other undesirable inclusions.

For example, in X-ray lithography, the object 12
If only a specific portion of the object 12 receives the X-rays, a space between the X-ray transparent portion 25 of the wall 22 and the object 12 is provided to prevent the X-rays from traveling toward other portions of the object 12. The mask 26 may be placed on the area.

The device also has a substantially fluid-tight intermediate chamber 34 adjacent to the first sealed chamber 16, the inner wall 19 of which has a portion in common with the wall 19 of the first sealed chamber; Further, the outer wall 19' is substantially parallel to the common wall 19, and the opening 20 in the common wall and the wall 35 of the second sealed chamber 18
have apertures 20' aligned between the transparent portions 20' or 36 of the
0' to the wall 22 of the second sealed chamber 18. The gas in the intermediate chamber 34 is discharged in the direction indicated by the arrow 17' by a pressure reducing means (not shown) to maintain the internal pressure at a value between the pressures in the first and second sealed chambers. The opening 20' in the outer wall is small so that the pressure reducing means can evacuate gas from the intermediate chamber at least at the velocity of the gas passing through the opening.

The device shown in FIG.
4' are positioned on both sides of the wall 19' with which they are common, and the openings 20', 20'' are connected to the first sealed chamber 16.
It is positioned between and in alignment with the opening 20 in the wall 19 and the radiolucent portion of the wall 35 of the second sealed chamber 18 . The gas therein is discharged from the second intermediate chamber 34' in the direction indicated by the arrow 17'' by a pressure reducing means (not shown), so that the internal pressure of the second intermediate chamber 34' is between the internal pressures of the chambers adjacent on both sides of the intermediate chamber. The openings 20', 20'' are made sufficiently small to allow the pressure reducing means to evacuate gas from each intermediate chamber at least at the same rate as the air entering the intermediate chamber therethrough.

The pressure in the intermediate chamber 34, 34' is maintained logarithmically midway between the pressures on either side of the substantially parallel walls 19, 19', 19''. For example, in the first sealed chamber 16 approximately 1 Torr. (torr), approximately 10 in the intermediate chamber 34
Torr, approximately 100 Torr in the intermediate chamber 34'. The space between the outer wall 19'' of the intermediate chamber 34' and the wall 35 of the second sealed chamber 18 (typically about 0.1 to 2 millimeters) is of course at atmospheric pressure, about 760 Torr. If 34, 34' are provided, a different exhaust system of the type used to radiate the electron beam to the atmosphere may be desirable.

The spacing between the parallel walls 19, 19', 19'', 35 is sufficiently large to prevent gas from flowing from these walls. Typically, the inner wall 19 and the outer wall 19 of the first intermediate chamber 34 The distance between the walls 19', 19'' of the additional first intermediate chamber is approximately 0.5 to 5 mm, and the parallel walls of the additional intermediate chamber (or The spacing (such as between walls 19'' and 35) is approximately 0.1 to 2 mm.
It is sized so that the line passes through it to form a cone having an apex angle A of about 1 to 10 degrees.

In some exemplary embodiments of the invention, as shown in FIG. 3, the second sealed chamber 18 comprises a lightweight gas drift tube. That is, the chamber typically contains a gas of helium, hydrocarbon or hydrogen, preferably helium, at about atmospheric pressure. A typical closed chamber wall 35 to wall 22 distance will be approximately 0.5 to 5 meters, typically 0.5 to 2 meters. Typically, the X-ray transparent portion 36 of wall 35 and the X-ray transparent portion 25 of wall 22 are constructed of thin foil material consisting essentially of beryllium or low Z plastic. The atomic number Z of the foil material is not greater than 8. The thickness of the foil material is approximately 2 to 20 microns.

In some embodiments of the invention, as shown in FIG. Radiolucent gas 24 is supplied to chamber 18 in the direction of arrow 23 at least at such a rate that it leaves opening 20', preventing other gases from entering chamber 18. Typically at least a wall 22
The gas in the second sealed chamber near the x-ray transparent portion of the tube is maintained at about 0.9 to 1 atmosphere.

Typically, the gas 24 introduced into the second sealed chamber 18 is a hydrocarbon such as helium, hydrogen or methane, and at least the X-ray transparent portion 2 of the wall 22
5 is considered to be 0.9 to 1 atm. Preferably,
Helium gas is known to be substantially inert and highly transparent to X-rays.

The X-ray transparent portion 25 of the wall 22 is formed from a low Z plastic material or a thin foil material 25 consisting essentially of beryllium. The thickness of the foil material 25 is approximately 2 to 20 microns. Other plastic materials having an atomic number Z not greater than about 8 may be used. If a material with low X-ray transparency is used, its thickness must be extremely thin.

The pressure of the gas 24 in the second closed chamber 18 is maintained at approximately atmospheric pressure, so that the X-ray transparent portion 25 of the wall 22 can be made very thin since the pressure on both sides thereof is approximately the same. To substantially separate the gas 24 inside the second sealed chamber 18 from the surrounding air, a gas curtain alone, rather than a solid material, can be used, or a mask 26 of FIG. 1 or a mask 26 of FIG. sample 32 can be placed against a thin frame created by wall 22. If no adjacent mask or sample is used, placing the object 12 against a wall 22;
The gas within chamber 18 can be separated from the surrounding air.

Gas 24 in the second closed chamber 18, at least on the wall 2
If the gas 24 near the X-ray transparent portion 25 of the second closed chamber 18 is maintained at approximately atmospheric pressure, the X-ray transparent portion may have an opening and the gas 24 in the second sealed chamber 18
4 is connected to the opening 2 by means of a gas curtain flowing along the opening 25 or placed against the wall 22.
5 (such as the mask 26 in FIGS. 1 and 3 and the sample 32 in FIG. 2) can be substantially separated from the air.

As shown in FIG. 2, a typical apparatus according to the present invention for obtaining EXAF data of a material also directs spectrally analytical Spectral dispersion means, such as a monochromator 30, can be provided in the second sealed chamber 18 to direct the spectral dispersion. Object 12 typically includes a recording medium such as photographic film 12. Such a device can also be used either inside the second sealed chamber 18 as indicated by the dotted line 31 or outside the second sealed chamber 18 between the X-ray transparent part 25 and the recording means 12 as indicated by 32. Support means (not shown) may also be provided for positioning the material sample 31 in the optical path of the X-rays 11, 11R at that location. Position 32 is more convenient than a position (such as 31) within the second sealed chamber 18.

Typically, the high energy 14 is applied in a single pulse to produce a single pulse of soft x-rays 11 suitable for obtaining an EXAFS spectrum of the material 32 as an element with an atomic number less than 40 in most cases. Aim at the target 15 as follows.

The EXAFS device, as shown in FIG. 2, also rotates and moves the surface of the target 15 in a helical manner, causing the trajectory of the focal point 28 on the cylindrical surface of the target 15 to be impinged by the high energy 14 of the laser. It may also include means for. In that case, the energy beam 14 is directed at a point 28 on the target surface moving in a series of pulses to produce soft x-rays 11.

Preferably, the X-rays from target 15 are emitted continuously over a selected spectral range of sample 32. Typically, target 15
contains the EXAFS spectral range of the selected material and consists essentially of elements with a continuum just above the L line. Alternatively, target 15 may include multiple elements having lines close enough to form a virtual continuum in the selected EXAFS spectral range of sample 32. Such targets 15 typically include a mixture of components with adjacent atomic numbers.

The high energy typically consists of laser pulses 14 having a power density of at least about 10 ¹³ watts per square centimeter, and the target 15 typically includes a solid (typically metal) surface to generate a surface plasma. is formed and rises to the kilovolt temperature range. However, approximately 10 ¹¹ per square centimeter
Some types of EXAFS can be obtained in the ultraviolet and ultra-soft X-ray regions using power densities down to watts. Laser pulse 14 is focused to impinge on a focal point 28 on target 15, approximately 1 to 200 microns in diameter.

More typical and preferred details of an apparatus of the type shown in FIG. 2 for obtaining EXAFS data for materials are described in US Pat. No. 4,317,994.

The means for directing the high energy to the target includes a lens 13 that focuses the laser beam 14 from a laser 27 through a window 29 in the first sealed chamber 16 to a point 28 on the target 15 about 1 to 200 microns in diameter. ing. Typically, aperture 20 in common wall 19 will have a diameter of about 0.2 to 2 mm, and the distance between aperture 20 and point 28 on target 15 will be about 0.2 to 5 cm. The X-rays generated at target 15 have an energy of approximately 0.3 to 2 KeV.

Energy from a laser is directed onto a target in a typical method for producing the x-rays used in the present invention, which is described in detail in the aforementioned US patents cited in the Background section of this specification. By focusing the radiant energy of a low power precursor pulse of approximately uniform effective intensity onto the target surface for approximately 1 to 30 nanoseconds,
The overall density is less than the normal solid density, with a low density (under density) part where the plasma frequency is less than the laser radiation frequency and a high density (over density) part where the plasma frequency is higher than the laser radiation frequency. Conversion efficiencies of at least about 3 percent can be obtained by generating an expansive, unrestricted coronal plasma with a plasma concentration of about 10 ^-3 to about 30 nanoseconds after the pioneer pulse impinges on the target.
A main pulse of high power is emitted that is focused towards the plasma for 30 nanoseconds and has a power density and total energy such that radiant energy is absorbed by the under-dense portion and conducted to the over-dense portion to heat it. generates X-rays with the plasma remaining substantially below the normal solid density by do.

Targets typically have a high atomic number Z, i.e. 10
It is basically composed of components having the above atomic numbers. Typically, targets consist essentially of iron, calcium, chrome, nickel, aluminum, lead, tungsten, or gold.

Typically, the amplitude, duration, and shape of the pioneer pulse are adjusted to control the intensity and spectral content of the x-rays. The precursor pulse is typically about 0.01 to 5 joules (about 10 ^{to 10 12} watts per square centimeter) for about 1 to 30 nanoseconds and impinges on the target at an angle of about 20 to 70 degrees from its surface. .

The main pulse is typically at least 0.1 joules, preferably 10 to 200 joules, for about 1 to 3 nanoseconds.

In a typical embodiment, the target is composed essentially of iron and the duration of the pioneer pulse is about 8 to 10 nanoseconds.

The electron density in the low density part of the plasma is typically about 10 ¹⁶ to 10 ²¹ per cubic centimeter and in the high density part about 10 ¹⁹ to 10 ²⁵ per cubic centimeter. The radiant energy is concentrated at a point on the target, typically about 1 to 1000 microns in diameter. The volume of the plasma is typically about 10 ^-6 to 10 ^-3 cubic centimeters, and the plasma thickness in any direction is about
It is 0.001 to 0.1 cm.

For low energy applications, X-rays are emitted predominantly in the form of spectral lines.

The radiant energy is transmitted to a diameter of approximately 1 to 100 microns.
Generating a plasma that is concentrated at a point on the target and of approximately the same diameter to form a generally point source of x-rays provides the substantial advantage of stimulated emission of x-rays.

In some embodiments of the invention, the composition of the target and the temperature of the plasma are selected to result in stimulated emission of a significant amount of x-rays.

In other embodiments, the x-rays are directed to impinge on a fluorescent target, thereby removing core electrons from the atom and causing population inversion.

In the typical method of providing stimulated emission of x-rays by directing radiant energy to a target and creating certain upper and lower laser levels with a pumping mechanism, the pumping mechanism alone does not provide the necessary population reversal;
Inversion is accomplished by combining the pumping mechanism with a quenching mechanism that annihilates the lower laser level at a rate sufficient to effect and maintain the inversion continuously. Pumping mechanisms typically consist of excitation through electron and ion collisions or dielectric recombination. Extinction mechanisms typically consist of Auger transitions, Coster-Kronig transitions, or collisions. The radiant energy may be generated from a laser or may consist of an electron beam. The pumping mechanism may include an electron beam.

The device according to the invention is suitable for applications where it is expensive, time consuming, or inconvenient to move objects to be subjected to soft x-rays into and out of special environments such as vacuum chambers where the x-rays are produced. Particularly useful. Typical applications of this type include laser-based x-ray devices for high resolution lithography, extended x-ray absorptive microstructure (EXAFS) spectroscopy, and x-ray microscopy.

Although X-rays are usually produced in a vacuum, in many applications it is desirable to apply them in air. Particularly for soft x-rays, such as those with photon energy of approximately 5 KeV, a window made thick and strong enough to withstand the pressure difference between vacuum and air is non-conducting and therefore There are problems with taking it out of the vacuum and into the air. This problem is particularly acute in the case of X-ray trigraphy, where it is preferable to irradiate a large area.

The present invention provides a simple, inexpensive, and convenient apparatus for overcoming the problems of irradiating objects with X-rays in a normal environment, such as air at approximately atmospheric pressure.

The method according to the invention is useful and advantageous not only for X-ray lithography, but also for laser EXAFS, and in particular for high-speed EXAFS spectroscopy using a single pulse of laser-generated X-rays or multiple pulses of said X-rays. It is.

EXAFS spectroscopy techniques can be used to analyze long-range materials such as amorphous solids, solutions and gases of biologically important materials.
It has become an increasingly important tool for studying chemical structures in samples lacking order. These studies have been spurred in recent years by the availability of synchrotrons, which provide the continuous and intense spectrum of soft x-rays needed for EXAFS. However, synchrotrons are expensive and require scientists to travel to the location to perform their experiments. On the other hand, laser-based x-ray sources are relatively compact, inexpensive, and easy to operate and maintain. In addition, a variety of novel
EXAFS experiments can be performed. These experiments, which require short pulse widths, intense fluxes of low-energy (below 4 KeV) ideally suited for X-rays.

EXAFS spectra of aluminum were measured using soft x-rays with 1 nanosecond pulses created by laser-generated x-rays. This technique provides a practical alternative to synchrotron radiation for EXAFS data acquisition. It also provides unique capabilities for analyzing the molecular structure of highly transitional chemical samples.

Although the form of the invention presented herein constitutes a presently preferred embodiment, many other embodiments are possible. It is not intended here to describe possible equivalents of the details of the invention. Furthermore, the terminology used herein is not limiting and is merely for descriptive purposes, and various changes can be made without departing from the spirit or scope of the present invention.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view of an exemplary apparatus according to the present invention; FIG. 2 is a schematic plan view of an exemplary embodiment of the present invention for collecting EXAFS data of materials; FIG. FIG. 3 is a schematic diagram of another exemplary embodiment. In the figure, 11, 11R...X-ray, 12...
Object, 13...Lens, 14...Energy, 1
5...Target, 16...First sealed part, 18
...Second sealed part, 20, 20'...Opening, 21
...Gas, 22...Wall, 24...X-ray transparent gas, 25...X-ray transparent portion, 27...Laser,
28... focus, 30... monochromator, 34,
34'...middle room.

Claims (1)

[Claims] 1. A device for irradiating an object with X-rays in a normal environment such as air at approximately atmospheric pressure, which directs energy toward the target and applies X-rays having a selected spectrum and intensity to the target. means for creating at the target; a first substantially fluid-tight sealed chamber around the target; and reducing the amount, and thus the pressure, of the gas within the first sealed chamber. depressurization means for maintaining the pressure substantially below atmospheric pressure; a substantially fluid adjacent to the first sealed chamber containing a gas having high transparency to X-rays to the exclusion of other gases; a second hermetically sealed chamber; one wall of the first hermetically sealed chamber having an opening large enough to allow the passage of X-rays through which gas enters the first hermetically sealed chamber; the target is arranged sufficiently close to the opening, and the target is arranged sufficiently close to the opening; a first wall of the second sealed chamber is positioned to direct a substantial portion of the generated x-rays toward and through the aperture; a first wall of the second sealed chamber is highly transparent to the x-rays; an X-ray transparent portion positioned adjacent to the opening in the wall of the sealed chamber, the X-rays passing through the opening passing through the X-ray transparent portion and a second the gas in the second sealed chamber is maintained at a pressure approximately equal to atmospheric pressure at least in the vicinity of the second wall; and the second wall of the second sealed chamber has an X-ray transparent portion that is highly transparent to X-rays directed toward it, thereby providing a second wall adjacent to the X-ray transparent portion. irradiating the object with X-rays that are substantially unhindered by air or other undesirable inclusions by positioning the object outside the second sealed chamber. device to do. 2. An inner wall having a part in common with a part of the wall of the first sealed chamber having the opening, and an X-ray transparent part of the opening and the first wall that is substantially parallel to the inner wall. an outer wall having a second aperture aligned with the outer wall of the first enclosure, the outer wall having a second aperture aligned with the outer wall of the first enclosure, the first enclosure having an outer wall having a second aperture aligned with the outer wall thereof, the first enclosure having an outer wall having a second aperture aligned with the outer wall of the first enclosure, the first enclosure having an outer wall having a second opening aligned with the outer wall of the first enclosure; a substantially fluid-tight intermediate chamber adjacent to the chamber; reducing the amount of gas, and therefore the pressure, in the intermediate chamber so that the pressure in the intermediate chamber is equal to the pressure in the first sealed chamber and the pressure in the second sealed chamber; a second pressure reducing means for maintaining the pressure at a value between;
The opening is so small that the amount of gas entering the intermediate chamber through the opening is at most the same as the amount of gas exhausted from the intermediate chamber by the second pressure reducing means. Apparatus described in section. 3 at least one additional intermediate chamber provided between the first and second closed chambers, the intermediate chambers of adjacent pairs being arranged on opposite sides of one common wall provided with an opening;
an additional intermediate chamber in which the opening in the common wall is aligned between said opening in the wall of the first sealed chamber and the X-ray transparent portion of the first wall of the second sealed chamber; reducing the amount of gas in the chamber and therefore its pressure;
means for maintaining the pressure in said intermediate chamber at a value intermediate between the pressures in adjacent chambers; and said opening in said common wall is configured such that the amount of gas entering the additional intermediate chamber through said opening is depressurized from said intermediate chamber. 3. The device according to claim 2, wherein the amount of gas is at most the same as the amount of gas emitted. 4. Apparatus according to claim 3, wherein the pressure value in each intermediate chamber is maintained logarithmically midway between the pressure values in adjacent chambers. 5. The apparatus of claim 3, wherein the spacing between the common walls of the intermediate chamber is sufficiently large to prevent gas flow therebetween. 6 The distance between the inner and outer walls of the first intermediate chamber is approximately 2
4. Device according to claim 3, characterized in that the distance between the common walls of the first additional intermediate chamber is between 0.5 and 5 mm. 7 Furthermore, the distance between the common walls of the additional intermediate chamber is
The device according to claim 6, having a thickness of 0.1 to 2 mm. 8. The apparatus of claim 3, wherein the aperture is sized such that the x-rays passing therethrough are conical with an apex angle of 1 to 10 degrees. 9. The apparatus of claim 1, wherein the second sealed chamber comprises a lightweight gas drift tube. 10. The device according to claim 9, wherein the gas in the second sealed chamber is helium, hydrogen, or hydrocarbon. 11. The device according to claim 9, wherein the gas in the second sealed chamber is helium. 12. The device according to claim 9, wherein the gas pressure in the second sealed chamber is substantially atmospheric pressure. 13. The apparatus of claim 9, wherein the distance from the first wall to the second wall of the second sealed chamber is approximately 0.5 to 5 meters. 14. Claim 9, wherein the X-ray transparent portion of the first wall of the second sealed chamber is formed from a thin foil material.
The equipment described in section. 15. Claim 1, wherein the X-ray transparent portion of the second wall of the second sealed chamber is also formed from a thin foil material.
The device according to item 4. 16. The apparatus of claim 15, wherein said foil material comprises beryllium or a low Z plastic material. 17. The apparatus of claim 16, wherein the foil material has a thickness of about 2 to 20 microns. 18 The X-ray transparent portion of the first wall of the second sealed chamber has an opening and the highly X-ray transparent gas
supplying the second sealed chamber with the velocity of the gas exhausted from the second sealed chamber through the opening in the wall, thereby
2. A device as claimed in claim 1, further comprising gas supply means for substantially preventing the entry of other gases into the closed chamber. 19 The gas supplied to the second sealed chamber is helium,
Claim 18 regarding hydrogen or hydrocarbon
The equipment described in section. 20. The device according to claim 18, wherein the gas supplied to the second sealed chamber is helium. 21 The gas pressure in the second sealed chamber is at least as high as
Approximately 0.9 to 1 near the radiolucent part of the wall
19. The apparatus of claim 18 maintained at atmospheric pressure. 22. The apparatus of claim 21, wherein the X-ray transparent portion of the second wall of the second sealed chamber is comprised of a thin foil material. 23. The device of claim 22, wherein the foil material is beryllium or a low Z plastic material. 24. The device according to claim 23, wherein the thickness of the foil material is between 2 and 20 microns. 25 The X-ray transparent portion of the second wall of the second sealed chamber has an opening, and the gas in the second sealed chamber is directed by a gas curtain passing along the opening or by contacting the second wall and covering the opening. 2. The apparatus of claim 1, wherein the object to be irradiated with X-rays or a member associated with the object is arranged to be substantially isolated from surrounding air. 26 positioned to receive the X-rays passing through the aperture and direct the spectrally resolved X-rays toward an X-ray transparent portion of the second wall adjacent to the object to be irradiated with the X-rays; 2. Apparatus according to claim 1, comprising spectral spreading means in a second closed chamber for obtaining EXAFS data of a substance, the object comprising recording means. 27. Apparatus according to claim 26, comprising means for positioning a sample of material in the optical path of the X-rays. 28. The apparatus of claim 27, wherein the sample is positioned within a second closed chamber. 29. The apparatus of claim 27, wherein the sample is positioned outside the second sealed chamber, between an X-ray transparent portion of the second wall and a recording means. 30. The apparatus of claim 1, wherein said energy directing means includes means for directing energy from a laser to a target. 31. The apparatus of claim 1, wherein the energy directing means includes means for focusing the energy to a point on the target having a diameter of about 1 to 200 microns. 32. The device of claim 1, wherein the opening in the wall of the first closed chamber has a diameter of about 0.2 to 2 mm. 33. The apparatus of claim 1, wherein the distance between the opening in the wall of the first chamber and said point on the target is about 0.2 to 5 centimeters. 34. The apparatus of claim 1, wherein the x-rays produced by the target have an energy of approximately 0.3 to 2 KeV.