6-mirror-system EUV projection optics design with NA of 0.4 plus was improved and the residual wavefront error was
much reduced. Apodization is an issue for such high-NA EUV projection optics. Broad-band multilayer mirror can solve
the problem. Broad-band multilayer mirrors were developed. Measured reflectivity performance of these multilayers was
in good agreement with the designed performance. We have decided the measures to control contaminations of optics in
HVM EUV exposure tools.
Hard X-ray telescopes using depth-graded multilayer is a key technology for future satellite programs. Developments
are underway by many groups, and balloon experiments have also been carried out. We have developed
light-weight hard X-ray telescopes using Pt/C multilayer and high-throughput thin-foil optics. They have been
aboard on InFOCμs and SUMIT balloon flights. As a next development efforts, especially for Japan's NeXT
satellite program, we focus on improvement of image quality. Among three equally-contributing error factors
(figure error, positioning error and off-roundness), figure errors and off-roundness have been reduced significantly, by screening of replication mandrels and active and iterative tuning of support bars. Further studies are
in progress, such as suer-polished metal mandrels and better positioning of reflector edges, to meet the baseline
requirement of the NeXT mission.
We report on a new photon-counting detector possessing unprecedented spatial resolution and moderate spectral resolution for 0.5-100keV X-rays. It consists of an X-ray charge-coupled device (CCD) and a scintillator. The scintillator is directly coupled to the back surface of the X-ray CCD. Low-energy X-rays below 10keV can be directly detected by the CCD. The majority of hard X-rays above 10keV pass through the CCD but can be absorbed by the scintillator, generating visible photons. We employ the needlelike CsI(Tl) in order to prevent the lateral spread of visible photons. We performed the Monte Carlo simulation with DETECT2000 both to maximize the number of visible photons detected by the CCD and to minimize the lateral spread of visible photons on the CCD. We then fabricated the optimized needlelike CsI(Tl) with 300 μm thick and coupled it on the front surface of the back-illuminated (BI) CCD. The high detection efficiency of BI CCDs in the visible band enables us to collect visible photons emitted from the CsI(Tl) efficiently, leading to the moderate spectral resolution of 30% at 59.5keV combined with the high detection efficiency for hard X-rays. We plan to perform the hard X-ray imaging balloon-borne experiment, SUMIT, in autumn of 2006 at Brazil. We also describe the details about the balloon system of the SD-CCD.
Japan's 6th X-ray satellite mission NeXT has completed pre-Phase-A study, and is waiting to advance to Phase-A/B. The X-Ray Telescope System onboard NeXT covers wide energy range from 0.3 to 80 KeV. The paper reviews current status on design and technology of the mission as written in the NeXT Mission Proposal on Oct. 2005.
The relevance of pre-flight calibration of space-born instruments is widely recognized. As an energy region of interest shifts to hard X-rays in these years, measurement setup becomes difficult to be afforded or maintained by a laboratory- or small-collaboration-based resources. In 10 to 100 KeV region X-ray source that is bright and monochromatic enough to calibrate optics in detail is no longer available other than at synchrotron facilities. Focal length becomes longer and this is another aspect that is beyond capabilities of soft-X-ray-oriented facilities. The hard X-ray instruments for balloon program have been characterized at synchrotron facility SPring-8/BL20B2 in Japan. SPring-8 is one of the world's brightest third generation synchrotron radiation facilities. BL20B2 is specialized for medical and imaging experiment, and has 200m-long transport tube. Measurement at BL20B2 has great advantages such as extremely high flux, large sized and less divergent beam, and monochromatic beam covering entire hard X-ray region from 8 to 12keV. 16m-long experiment hutch is capable of long focal length of hard-X-ray telescope. Pt/C multilayer-supermirror hard X-ray telescopes, position-sensitive scintillation counter and scintillator-deposited CCD, have been characterized at the facility. Insttrumentation of the facility and some of measurement results are presented.
Imaging observation in the hard X-ray band of 10 - 100 keV is one of the important subjects in X-ray astronomy.
Though SUMIT balloon-borne experiment, we have developed thin-foil-nested hard X-ray telescope employing
depth-graded Pt/C multilayer (multilayer-supermirror). We have improved production process of the replica
reflector and telescope optics compared with InFOCμS-2004 telescope. The new telescope was measured at
synchrotron radiation facility, SPring-8. The image quality and throughtput were estimated to be 2.06 arcmin
(half power diameter) and 85 % at 30 keV, respectively. These values were about 24 % and 30 % improvement
compared to InFOCμS-2004, respectively. Limiting factors of its performance are also investigated. Based on
such an investigation we are now continuously developing hard X-ray telescope for SUMIT 2006 flight.
We have been developing position sensitive scintillation counter as focal plane detector of hard X-ray telescope onboard a balloon borne experiment. This detector consists NaI(TI) scintillator and position sensitive photo-multiplier tube. Focal plane detector has to have high efficiency in hard X-ray region, enough position resolution and detection area. 3mm thickness of NaI(TI) scintillator can achieve almost 100% efficiency below 80 keV. We measured position resolved energy and position resolution in synchrotron radiation facility SPring-8 BL20B2. Position resolution of 2.4mm at 60keV is about half of plate scale of half power diameter of X-ray telescope. The detector has 6 cm diameter window and it corresponds to 25 arcmin field of view, and it is enough lager than the that of telescope, which is 12 arcmin in FWHM. Balloon borne experiment for observation of the background was performed on May 24, 2005 from Sanriku balloon center. We could obtain background data for 3 hours at altitude of 40 km.
To search for warm-hot intergalactic medium (WHIM), a small satellite mission DIOS (Diffuse Intergalactic
Oxygen Surveyer ) is planned and a specially designed four-stage X-ray telescope (FXT) has been developed as
the best fit optics to have a wide field of view and a large effective area. Based on the previous works such as the
design of optics and replica foil mirror fabrication, we made the demonstration model of the FXT, which has a
set of four-stage mirror supported by alignment plates to reduce alignment errors between different stages. On
the selection of mirror surface metrial, we tried to increase the reflectivity of gold or platinum replica mirror
at low energies. We are also trying to make Ni replica mandrel having the shape of four different cone angles
for developing a full or partial shell of four-stage mirror formed in a same substrate. We describe the expected
performance and alignment procedure of the demonstration model, the present status of the selection of mirror
surface material and the development of Ni mandrel.
Hard X-ray telescope by means of optics is one of the key technologies for future X-ray observatory programs. Introducing a telescope to hard X-ray region above 10 keV will improve sensitivity by one or two orders of magnitude. The principle of hard X-ray telescope is a depth-graded multilayer (supermirror) and high throughput, nested thin-foil grazing incidence optics. We have successfully developed a hard X-ray telescope sensitive up to 50 keV for balloon program InFOCuS. Effective area of 50 cm2 at 30 keV and image quality of 2.5 arcmin (HPD) were obtained from ground-based measurement and were also confirmed by in-flight calibration.
Recent development achieved an improvement of image quality roughly by a factor of two. Japan's future X-ray satellite program NeXT has been proposed based on our technology.
The DIOS, Diffuse Intergalactic Oxygen Surveyor mission, is planned to observe diffuse soft X-rays, which might originate from warm-hot intergalactic medium as a target of missing baryon and as a probe of dark matter. To observe very weak diffuse soft X-rays, the FXT, four-stage X- ray telescope, is specially designed to have wide field of view and large effective area for the small satellite DIOS. It is confirmed that FXT meets basic requirements of the DIOS mission based on the ray tracing analysis. Al-foil based epoxy replication method is applied to the fabrication of element mirror of the FXT. Several tens of foil mirrors were fabricated and measured their performance. Mirror material combination was also reviewed from the view point of line observation other than oxygen.
This paper presents characterization of hard X-ray telescope using synchrotron facility, mainly on experimental setup, benefits of such experiment, and measurement results only available by means of bright synchrotron light. We have developed hard X-ray telescope consisting of Wolter-I grazing incidence optics with platinum-carbon multilayer supermirror surfaces. Telescopes have been fabricated for InFOCuS balloon experiment, and we achieved first scientific flight in 2004. The hard X-ray telescope on board InFOCuS has been characterized at synchrotron facility SPring-8/BL20B2, Japan. Measurement at BL20B2 has great advantages such as extremely high flux, large sized and less divergent beam, and monochromatic beam covering entire hard X-ray region from 8 to over 100keV. A 16m-long experiment hutch is another feature suitable for measurements of hard X-ray telescopes. The telescope was illuminated by monochromatic hard X-rays, and focused image was measured by high resolution hard X-ray imager. Whole telescope aperture was mapped by small beam, and effective area and point spread function are obtained as well as local optical properties for further diagnostics of telescope characteristics.
We have been developing X-ray mirrors for X-ray telescope using a ion-beam sputtering system. X-rays can be reflected by two processes, one is total reflection, and another is Bragg reflection. Total reflection is used for previous telescope below 10 keV. Its reflectivity determined by the optical constant. We suggests composite-layer mirror for soft X-ray optics, which has consists some different materials and optical constant has structure to the depth direction. The penetration depth of X-ray depends on the X-ray energy, so effective optical constant changes with X-ray energy. The depth graded multilayer, called "supermirror" was applied to the soft X-ray region. We designed nickelcarbon supermirror to obtain high reflectivity below 10 keV.
The development of hard X-ray focusing optics for astrophysical observation is widely recognized as one of key technologies for future X-ray satellite missions. Utilizing InFOCμS balloon-borne experiment, we have developed thin-foil-nested hard X-ray telescope employing depth-graded Pt/C multilayer. Pre-flight calibration of the hard X-ray telescope for the 2004 flight was performed at X-ray beamline facilities in ISAS/JAXA and SPring-8. The effective area and image quality were estimated to be 51 cm2 and 2.4 arcmin (half power diameter) at 30 keV, respectively. Limiting factors of its performance also investigated. And we revealed that the main factor was image degradation of an individual reflector. Based on such an investigation we are now continuously developing advanced hard X-ray telescope for future balloon experiments. From evaluation of upgraded test telescope, we get a response toward high resolution telescope in future years.
As technological and scientific path-finder towards future observatory missions, a balloon-born hard X-ray imaging observation experiment InFOCμS has been developed. The payload has flown four times since 2000. In its 2004 Fall flight campaign InFOCμS successfully achieved first scientific observations of multiple astronomical objects from galactic compacts to cluster of galaxies. Significant signal has been detected from bright galactic objects while analysis of extragalactic objects is underway. InFOCμS plans additional and upgraded telescope-detector system as early as 2006. High energy telescope for nuclear gamma-ray line observations is under planning.
We present X-ray characteristics of X-ray telescopes (XRTs) onboard the Astro-E2 satellite. It is scheduled to be launched in February 2005. We have been performed X-ray characterization measurements of XRTs at Institute of Space and Astronautical Science (ISAS) since January 2003. We adopted a raster scan method with a narrow X-ray pencil beam. Angular resolution of the Quadrants composed of the Astro-E2 XRT was evaluated to be 1'.6-2'.2 (HPD; Half Power Diameter), irrespective of the X-ray energy, while those of the Astro-E XRT was 2'.0-2'.2. The effective area of a telescope is approximately 450, 330, 250, and 170 [cm2] at energies of 1.49, 4.51, 8.04, and 9.44 keV, respectively. The field of view (FOV) of the XRTs which is defined as Full Width Half Maximum (FWHM) of the vignetting function is ≈18' at 4.51 keV. We summarize these characters of the XRTs.
We report a ground-based X-ray calibration of the Astro-E2 X-ray
telescope at the PANTER test facility. Astro-E2, to be launched in
February 2005, has five X-Ray Telescopes (XRTs). Four of them focus on
the X-Ray Imaging Spectrometers (XIS) while the other on the X-Ray
Spectrometer (XRS). They are designed with a conical approximation of
Wolter-I type optics, nested with thin foil mirrors to enhance their
throughput. A calibration test of the first Astro-E2 flight XRT for
XIS was carried out at the PANTER facility in August 2003. This
facility has an 130 meter long diverging beam from X-ray generator to
XRT. Owing to the small X-ray spot size of about 2 mm dia., we verified that the focal position of each quadrant unit converged within 10 arcsec. The energy band around Au-M edge structures was
scanned with a graphite crystal. The edge energy (Au M5) is consistent with that listed in Henke et al. 1997. Owing to the large area coverage of the PSPC detector which is a spare of the ROSAT satellite, off-axis images including stray lights at large off-axis angle (up to 6 degree) were obtained with a large field of view. We also compared the results with those measured with the parallel pencil beam at ISAS which is in detail reported in our companion paper by Itoh A. et al..
Hard X-ray focusing observation is important to reveal non-thermal
emission mechanism and origin in active galaxies and clusters of
galaxies. We have carried out the hard X-ray observation throughout
the ¥infocus program, which is an international balloon-borne
experiment in collaboration with NASA/GSFC and Nagoya University.
The telescope is conical approximation of Wolter-I optics with 8 m
focal length and 40 cm diameter. It consists of 255 nested thin (0.17
mm thickness) reflectors with incidence angles of 0.10° to
0.36°. Reflectors are coated with depth-graded platinum-carbon (Pt/C) multilayers, so-called supermirrors, with periodic length of 2.6 to 13 nm and bi-layer number of 28 to 79, depending on incidence angles. We are now continuously fabricating advanced next hard X-ray telescope for the second ¥infocus flight in 2004. Compared with the first telescope, the following improvements have been made on the second one. Supermirror reflectors have wider sensitivity in energy band of 20-60 keV adopting optimum supermirror design for balloon
observation, and smaller interfacial roughness owing to complete
replication technique. For upgrading of the image quality, we then
adopted stiffer reflector substrate, selected replication mandrel with
better shape, and the modified telescope housing with higher alignment
accuracy for reflectors. The performance of the new hard X-ray
telescope was measured in X-ray beamline facility in ISAS/JAXA and
synchrotron radiation facility SPring-8. The effective area and image
quality are obtained to be 45 cm2 at 30 keV and 23 cm2 at 40 keV, and 2.5 arcmin in half power diameter, respectively. In this paper we report our development of the upgraded hard X-ray telescope for the second balloon flight experiment.
NeXT is Japan's 6th X-ray astronomical observatory following to ASTRO-E2. The launch is currently scheduled in 2010. One of the main goal of NeXT is to explore the hard X-ray Universe with newly developed hard X-ray telescope. The hard X-ray telescope utilizes multilayer-supermirror and high-throughput thin-foil optics technology. Performance of the hard X-ray telescope has been demonstrated through InFOCuS balloon experiment. This paper describes principle, design, and technology background of the Hard X-ray Telescope on board NeXT.
Astro-E2, to be launched in early 2005, will carry five X-ray Telescopes (XRT). The design of the XRT is the same as the previous original mission Astro-E, that is a conical approximation of Wolter Type-I optics, where about 170 thin-foil reflectors are nested confocally. Some modifications from Astro-E are adopted within the severe constraints due to the policy of "re-build" instruments. One of the major changes is the addition of pre-collimators for the stray light protection. Several modifications on the fabrication processes are also made. The replication glass mandrels are screened carefully, which is expected to reduce the figure error of replicated reflectors. We thus expect better performance than Astro-E especially in imaging capability. In order to qualify the performance of the Astro-E2 XRT, we have started ground calibration program of XRT at 30 meter X-ray beam facility of the Institute of Space and Astronautical Science (ISAS). We have found positive improvements on the telescope performance from the Astro-E, which probably arise from the applied modifications. The on-axis half-power diameter (HPD) has been evaluated to be 1.6-1.7 arcmin, which is improved from the Astro-E (2.0 ~ 2.1 arcmin HPD). The on-axis effective areas of quadrants are larger than the average of Astro-E by about 5%. The on-axis effective areas of the XRT for X-ray Imaging Spectrometers (XIS) are approximately 460, 340, 260, and 190 cm2 at energies of 1.49, 4.51, 8.04, and 9.44 keV, respectively. The present paper describes the recent results of
the performance of the first flight assembly of the Astro-E2 XRT.
Astro-E2 XRTs adopt Wolter Type-I optics and have nested thin foil structure to enhance their throughput. But this structure allows stray X-rays to come from the sky outside of the XRT field of view. Stray lights contaminate focal plane images, especially in the case of extended source observations. We intend to mount pre-collimators on top of the ASTRO-E2 XRTs to intercept stray lights. According to the success for the engineering model pre-collimator to protect the stray lights efficiently, we proceeded to product flight model pre-collimators. Some improements are made for the flight model (FM) pre-collimator: the introduction of heat forming to make slats accurate cylindrical shape, the change of the groove shape of alignment plates and the change of the housing design. We also established the method of pre-collimator mounting. In X-ray measurements, stray light images and the flux of each stray component at any off-axis angles are measured with/without FM pre-collimator. The secondary only reflection component is reduced down to 3% at a larger off-axis angle than 30', and the backside reflection component becomes more remarkable. On the other hand, X-ray measurement of the effective area at on-axis with/without FM pre-collimator verifies that pre-collimator does not interfere the telescope aperture. In addition, the decrease of XRT field of view is ≤8%, which is the same as the ray-tracing simulations.
We have been developing the hard X-ray telescope for balloon borne experiment named InFOCμS. The first InFOCμS flight was carried out on July, 2001. In this flight, we obtained hard X-ray image of Cygnus X-1 above 20 keV. This is first observation with hard X-ray telescope using multilayers. In this mission, the platinum-carbon depth graded multilayers (supermirror) are used as X-ray reflectors combining multi nested thin foil optics to obtain enough efficiency in the hard X-ray region. They make us possible to obtain 40 cm3 effective area at 30 keV with 40 cm diameter of the telescope. After the first flight, the hard X-ray telescope was recovered without any damages, we measured performances of the telescope in synchrotron radiation facility SPring-8. We obtained the results, the half power diameter (HPD) is 2.4 arcmin and effective area is 38 cm2 at 30 keV. These results show that no degradation of the performances of the hard X-ray telescope was observed in this measurement. Furthermore, we begin to fabricate new hard X-ray telescope for future InFOCμS flight. The design of the multilayer supermirrors are improved to widen the energy band. The performances of this telescope including effective area and spatial resolution are measured using synchrotron radiation facility SPring-8 and ISAS 30 m X-ray beam line. The measured effective area is significantly larger than the first telescope especially above 30 keV.
X-ray telescopes (XRTs) of nested thin foil mirrors were developed for
Astro-E, the fifth Japanese x-ray astronomy satellite. Although the
launch was not successful, the re-flight of Astro-E mission is approved as Astro-E2 and will carry the same XRTs. Ground-based calibration of Astro-E XRT revealed that its image quality and effective area are somewhat worse than what are expected from the original design. Conceivable causes of these defects of the XRT performance (i.e., surface roughness, waviness, misalignment of
reflectors, and so on) are examined by X-rays and optical microscopic
measurements. In this paper, we distinguish quantitatively these
causes to limit the performance of the Astro-E XRT. Using the detail
measurements, we can attribute both degradation of the image quality
and a deficit of the effective area from the design values mainly to a
slope error with a mm scale in each reflector and shadowing effects of
neighboring reflectors due to various factors. There is still room
for improvement in the support system of reflectors (i.e., alignment
bars) in the XRT. One of the main aims of the mirror system calibration is to construct response function. Therefore, it is important that the development of a representative numerical model and its validation against extensive ground-based calibration. Taking account of the results of the pre-flight calibration and the microscopic measurements, we develop and tune a ray-tracing simulator which constructs the XRT response function for a point source at an arbitrary off-axis angle and spatial distributions of celestial X-ray sources.
The development of hard X-ray focusing optics is widely recognized as
one of key technologies for future X-ray observatory missions such as
NeXT(Japan), Constellation-X(US) and possibly XEUS(Europe). We have developed hard X-ray telescope employing depth-graded multilayers, so-called supermirrors. Its benefit is to reflect hard X-rays by Bragg reflection at incidence angles larger than the critical angle of total external reflection. We are now continuously fabricating platinum-carbon(Pt/C) supermirror reflectors for hard X-ray observations. In this paper we focus on our development of the
hard X-ray telescope for the first balloon flight observation
(InFOCuS) and its results. InFOCuS is an international balloon-borne hard X-ray observation experiment initiated by NASA/GSFC. InFOCuS hard X-ray telescope have been jointly developed by Nagoya University and GSFC. The telescope is conical approximation of Wolter-I optics with 8m focal length and 40cm diameter. It consists of 255 nested ultra-thin reflector pairs with incidence angles of 0.10 to 0.36deg. Reflectors are coated with Pt/C supermirrors with periodic length of 2.9 to 10nm and bi-layer number of 25 to 60, depending on incidence angles. The effective area and imaging quality are expected as 100 cm2 at 30 keV and 2 arcmin in half power diameter, respectively. The InFOCuS experiment was launched on July 5, 2001, from National Scientific Balloon Facility in Texas, USA. We successfully observed Cyg X-1, chosen for a calibration target, in 20-40keV energy band. We are planning to carry out next flight for scientific observations as soon as additional telescopes, detectors, and upgraded gondola system are implemented.
Normal incidence optics have been used with multilayers in EUV
region. The 2d of the multilayers has to be equal to the wavelength of
interest. At the same time, the reflectivity of the multilayers should
decrease with the increase of the interfacial roughness much faster
than grazing optics. In general, 2d of 10 nm is the shortest d-spacing
available for multilayers in normal incidence. As a challenge of shorter wavelength application, we made NiCr/C multiplayer mirror for the laboratory use at 4.47 nm(carbon K alpha line). The main dish of the Cassegrain optics is 20 cm diameter spherical mirror and the secondary mirror is a reflector in aspherical shape to correct astigmatisms. Its focal point is placed at the X-ray source to create a broad parallel beam of 20 cm in diameter. The flux of the parallel beam is slightly less than the expected value, and gradually decreases of 40% toward the outer region. The measured parallelism is about 25 arcsec, which is a little larger than the designed value. More pricise positioning of the focal point to the X-ray generator may reduce such divergence. The beam profile through a slit shows a core of about 20 arcsec and an extended tail which might be due to scattering tail by the roughness of 0.3 nm. An application of this system is demonstrated with the Astro-E X-ray telescope. The image core is sharper but the scattering tail is considerable. Even after the subtraction of the tail, still some wing is left. This system is bright and parallel enough to examine the optical alignment much faster than previous method, while careful measurements are necessary for quantitative calibration of X-ray telescopes.
ASTRO-E2 XRTs adopt Wolter Type-I optics and have nested thin
foil structure to enhance their throughput. But this structure allows
stray X-rays to come from the sky out of the XRT field of view. Stray light contaminates focal plane images, especially in the case of extended source observations. We intend to mount pre-collimators on top of the ASTRO-E2 XRTs to intercept stray light. On the other hand, reflection by the pre-collimator itself newly creates secondary stray light. To decrease these additional stray light as possible, the mil finish aluminium with its roller mark normal to the incident X-ray beam has been used for the slat material, whose reflectivity is reduced down to 1/20 of ideal specular reflection. Optical profilers tell us these samples have very rough surfaces, whose height varies with Σ; = 1-2 μm. According to the design parameters as are described in the related paper in this symposium (Paper I), an engineering model pre-collimator is fabricated with 46 slats out of 175. Before EM pre-collimator is mounted onto XRT, alignment plates are adjusted to align slats to the same position of XRT primary reflectors. In x-ray measurements, stray light images and the flux
of each stray light component at 30' off axis are measured
with/without EM pre-collimator. The secondary only reflection component is reduced down to 3.6%, and the backside reflection component becomes more remarkable. On the other hand, X-ray measurement of the effective area at on axis with/without EM pre-collimator verifies that pre-collimator does not interfere the telescope aperture. In addition, the decrease of XRT field of view is ~10%, which is the same as the ray-tracing simulations. As a whole, EM pre-collimator reduces stray light to 27% level with only ~10% decrease of the XRT F.O.V.
Next Japanese ASTRO-E2 satellite carries five X-ray telescopes (XRTs),
and the pre-collimators for the stray light protection will be
installed on them. The pre-collimator is composed of the vertical
foil cylinders which line up at the top of the primary reflectors of
the XRT. This configuration is effective to reject the stray light of
the 'secondary only' reflection, which is the most of the stray light
from large off-axis angles up to 70' to the focal plane detector
within 18' x 18'. If the height of the pre-collimator is 30 mm (15%
of the total height of XRT), we can protect all the "secondary only"
component at > 30' off-axis. The field of view will become only about
10% less due to the collimation effect of the 30 mm high
pre-collimator. However, new stray light component is generated by the
reflection and scattering by the pre-collimator itself, especially at
small off-axis angles. As a result, we estimate the total flux of the
stray light to be about 10% at 30' off-axis and 5% at 60' off-axis,
compared with the case without pre-collimators.
We report a new calibration system for large size X-ray optics at
ISAS. We adapted a 'dynamical' pencil beam collimated from an X-ray
generator, the maximum voltage for which is 50 kV. By combining two
stage systems for the X-ray generator and a collimator, the pencil
beam dynamically sweeps across a circular region of a telescope with
the radius of 60 cm at maximum. In this case, the X-ray telescope and
the focal plane detector are both statically fixed. A 4.4~m long rail
for detector stage and two positions of the telescope stage provide
focal lengths from 4.5 to 12 m, while the previous system can
accommodate 4.5 or 4.75 m focal length. The preliminary performance of
this system is summarized in this paper. For the post-Astro-EII
satellite, a hard X-ray multi-layer supermirror with an unprecedented
sensitivity up to 80~keV is strongly expected. This beam facility is of importance because the hard X-ray mirrors always require a long focal length of 8-12 m due to the small reflection angle (about 0.3 degree). Focal length and diameter of future telescopes are always decided by the boundary conditions of the mission at the last moment of the design freeze. Our new X-ray beam facility is designed to match with any kind of X-ray telescope parameters.
X-ray characterization measurements of capillary (X-ray Optical Systems Inc) were carried out at ISAS (Japan) X-ray beam facility. Since capillary system has a capability of collecting x-rays effectively by the small angle reflections in the narrow tubes, it is expected to apply it for the observation of astronomical x-ray objects. The depth of focus on the on-axis is 6 mm, and the image size at the focal plane is 0.4 mm (FWHM) with Cu-K. By using continuum x-ray (2 to 15 keV) beam, the on-axis efficiency was evaluated to be 20 %. The efficiency decreases gradually toward low energy range, this could be explained by the absorption effect of Si which is one of the constituent element of capillary tubes. The field of view is defined as the off-axis angle at which the efficiency becomes half of the on-axis value. The diameter of the field of view was 22', 19' at 4.51 keV and 8.04 keV, respectively. Capillary has no imaging capability, in other words, the light-concentrating direction is independent from the incident angle of x-ray beam. When the x-ray incident angle varies from -15' to +15', the focused images are distributed within 3'. From our measurements, we could confirm the performance of capillary and its potential for astronomical applications.
We present the first results of pre-flight calibrations of the x-ray telescopes on board ASTRO-E satellite. They adopt a thin foil-nesting Wolter Type-I optics, which is in principle the same as ASCA XRTs. Owing to a scale up of the telescope and a new technique of the reflector production, however, both the effective area and the imaging capability are improved. In the current measurements, the effective area is obtained to be 460, 313 and 250 cm2 per XRT at 1.49, 4.51, and 8.04 keV, respectively, which is significantly larger than that of ASCA by a factor of 1.5 and 2.5 at 1.49 keV and 8.04 keV. The point spread function also shows a better focusing capability than ASCA by a factor of 2, and the half power diameter is obtained to be 1.84 arcmin at 4.51 keV. The brightness of the stray light is obtained to be 2 X 10-5 counts s-1 mm-2 at the brightest part of the stray light image, in the case that the x-ray star with the on-axis intensity of 1 count s-1 is the source of the stray lights, which is almost the same with ASCA.
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