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SMI (SPICA Mid-infrared Instrument) is one of the three focal-plane science instruments for SPICA. SMI is the Japanese-led instrument proposed and managed by a university consortium. SMI covers the wavelength range from 10 to 36 μm with four separate channels: the low-resolution (R = 60 – 160) spectroscopy function for 17 – 36 μm, the broad-band (R = 5) imaging function at 34 μm, the mid-resolution (R = 1400 – 2600) spectroscopy function for 18 – 36 μm, and the high-resolution (R = 29000) spectroscopy function for 10 – 18 μm. In this presentation, we will show the latest design and specifications of SMI as a result of feasibility studies.

SMI (SPICA Mid-infrared Instrument) is one of the two focal-plane science instruments for SPICA. SMI is the Japanese led instrument proposed and managed by a nation-wide university consortium in Japan and planned to be developed in collaboration with Taiwan and the US. SMI covers the wavelength range from 12 to 36 μm with 4 separate channels: the low-resolution (R = 50-120) spectroscopy function for 17-36 μm, the broad-band (R = 5) imaging function at 34 μm, the mid-resolution (R = 1300-2300) spectroscopy function for 18-36 μm, and the high-resolution (R = 28000) spectroscopy function for 12-18 μm. In this paper, we show the results of our conceptual design and feasibility studies of SMI.

SMI (SPICA Mid-infrared Instrument) is one of the two focal-plane scientific instruments planned for new SPICA, and the Japanese instrument proposed and managed by a university consortium in Japan. SMI covers the wavelength range of 12 to 36 μm, using the following three spectroscopic channels with unprecedentedly high sensitivities: low-resolution spectroscopy (LRS; R = 50 - 120, 17 - 36 μm), mid-resolution spectroscopy (MRS; R = 1300 - 2300, 18 - 36 μm), and high-resolution spectroscopy (HRS; R = 28000, 12 - 18 μm). The key functions of these channels are high-speed dustband mapping with LRS, high-sensitivity multi-purpose spectral mapping with MRS, and high-resolution molecular-gas spectroscopy with HRS. This paper describes the technical concept and scientific capabilities of SMI.

We present the latest results of the sensitivity estimate for spectrometers of the SPICA Mid-Infrared Instrument (SMI). SMI has three spectroscopic channels; low resolution spectrometer (LRS), medium resolution spectrometer (MRS) and high resolution spectrometer (HRS). Taking account of the results of optical design of each spectrometer and the latest information of the expected performance of detector arrays, the continuum sensitivity for a point source, the continuum sensitivity for an extended source, the line sensitivity for a point source, the line sensitivity for an extended source, and the saturation limit are calculated for LRS, MRS and HRS and are provided in this paper.

We present the design, fabrication and test results for a dichroic mirror, which was primarily developed for the SPICA Coronagraph Instrument (SCI), but is potentially useful for various types of astronomical instrument. The dichroic mirror is designed to reflect near- and mid-infrared but to transmit visible light. Two designs, one with 3 layers and one with 5 layers on BK7 glass substrates, are presented. The 3-layer design, consisting of Ag and ZnS, is simpler, and the 5-layer design, consisting of Ag and TiO2 is expected to have better performance. Tape tests, evaluation of the surface figure, and measurements of the reflectivity and transmittance were carried out at ambient temperature in air. The reflectivity obtained from measurements made on mirrors with 5 layers were < 80 % for wavelengths, λ, from 1.2 to 22 μm and < 90 % for λ from 1.8 to 20 μm. The transmittance obtained from measurements made on mirrors with 5 layers were < 70 % for λ between 0.4 and 0.8 μm. Optical ghosting is estimated to be smaller than 10-4 at λ < 1.5 μm. A protective coating for preventing corrosion was applied and its influence on the reflectivity and transmittance evaluated. A study examining the trade-offs imposed by various configurations for obtaining a telescope pointing correction signal was also undertaken.

In this report we describe our development of a prototype inverse-polished mirror for the passive correction of the static and predictable wavefront errors (WFE) of space-based telescopes, in particular, especially for infrared coronagraphs. An artificial WFE pattern with a root mean square (rms) value of 350 nm was numerically generated to facilitate the design of the prototype mirror. The surface of the mirror is approximately flat, is 50.0 mm in diameter and 15.0 mm thick at the edge. The designed WFE pattern was constructed on the mirror surface by micro-polishing. Both the figure and roughness of the mirror surface were evaluated. The rms value of the measured surface figure was reduced to 135 nm after subtraction of the designed surface figure. The benefit of subtraction to mid-infrared coronagraph performance was simulated, which showed the contrast was improved by a factor of ~100 close to the core (closer than 10 λ/D where λ and D are the wavelength and telescope aperture diameter, respectively) of the coronagraphic image of a point source. An analysis of the power spectrum density shows that the lower frequencies in the WFE are well reproduced on the mirror, while the higher frequencies remain due to the limitations imposed on the controllable spatial resolution by the fabrication process. In this study, inverse-polished mirrors combined with deformable mirrors and their application to ground-based telescopes are also discussed. To fully explore the potential of the inverse-polished mirror, a systematic allocation of the error budget is essential taking into account not only the fabrication accuracy of the mirror but also an evaluation of the telescope and other factors with non-predictable uncertainties.

Mid-infrared Camera and Spectrometer (MCS) is one of focal plane instruments for SPICA (Space Infrared Telescope for Cosmology and Astrophysics), which have 3 m class 6 K cooled telescope. MCS will provide wide field imaging and low-, medium-, and high-resolution spectroscopic observing capabilities with 7 detectors in the wavelength range from 5 to 38 micron. Large format array detectors are required in order to realize wide field of view in imaging and wide spectral coverage in spectroscopy. We are planning to cover the wavelength range of 5-26 micron by Si:As IBC 2K x 2K and 20-38 micron by Si:Sb BIB 1K x 1K. The development status and their design including the electrical and thermal design are described.

We present the current status of the development of the SPICA Coronagraph Instrument (SCI). SPICA is a next-generation 3-meter class infrared telescope, which will be launched in 2022. SCI is high-contrast imaging, spectroscopic instrument mainly for direct detection and spectroscopy of extra-solar planets in the near-to-mid infrared wavelengths to characterize their atmospheres, physical parameters and evolutionary scenarios. SCI is now under the international review process. In this paper, we present a science case of SCI. The main targets of SCI, not only for direct imaging but also for spectroscopy, are young to matured giant planets. We will also show that some of known exoplanets by ground-based direct detection are good targets for SCI, and a number of direct detection planets that are suitable for SCI will be significantly increased in the next decade. Second, a general design of SCI and a key technology including a new high-throughput binary mask coronagraph, will be presented. Furthermore, we will show that SCI is potentially capable of achieving 10 -6 contrast by a PSF subtraction method, even with a telescope pointing error. This contrast enhancement will be important to characterize low-mass and cool planets.

AKARI, the Japanese satellite mission dedicated to infrared astronomy was launched in 2006 February and exhausted its liquid helium in 2007 August. During the cold mission phase, the Infrared Camera (IRC) onboard carried out an all-sky survey at 9 and 18µm with better spatial resolution and higher sensitivity than IRAS. Both bands also have slightly shorter wavelength coverage than IRAS 12 and 25μm bands and thus provide different information on the infrared sky. All-sky image data of the IRC are now in the final processing and will be released to the public within a year. After the exhaustion of the cryogen, the telescope and focal plane instruments of AKARI had still been kept at sufficiently low temperatures owing to the onboard cryocooler. Near-infrared (NIR) imaging and spectroscopic observations with the IRC had continued until 2011 May, when the spacecraft had a serious problem in the power supply system that forced us to terminate the observation. The IRC carried out nearly 20000 pointing observations in total despite of its near-earth orbit. About a half of them were performed after the exhaustion of the cryogen in the spectroscopic modes, which provided high-sensitivity NIR spectra from 2 to 5µm without disturbance of the terrestrial atmosphere. During the warm mission phase, the temperature of the instrument gradually increased and changed the array operation conditions. We present a summary of AKARI/IRC observations, including the all-sky mid-infrared diffuse data as well as the data taken in the warm mission phase.

AKARI, the Japanese satellite mission dedicated for infrared astronomy launched in 2006 February, exhausted its 180 litter liquid helium (LHe) in 2007 August. After the LHe exhaustion, the telescope and focal plane of AKARI have still been kept less than 50K by the onboard cryocooler and near-infrared (NIR) observations with the Infrared Camera (IRC) are continuing. The data reduction software optimized for the warm mission enables us to carry out efficient and sensitive observations in the NIR despite the increase of hot pixels. In particular, the NIR spectroscopic capability of the IRC provides a unique opportunity to obtain spectra in 2.5-5μm with a high sensitivity, which will not be able to be carried out with any other facilities until JWST. An overview of the AKARI warm mission is given together with the performance and some observational results taken during the warm mission.

Bright source catalogues based on the new mid- and far-infrared all-sky survey by the infrared astronomical satellite AKARI were released into the public domain in March 2010. The mid-infrared catalogue contains more than 870 thousand sources observed at 9 and 18 μm, and the far-infrared catalogue provides information of about 427 thousand sources at 65, 90, 140, and 160 μm. The AKARI catalogues will take over the IRAS catalogues and will become one of the most important catalogues in astronomy. We present the characteristics of the AKARI infrared source catalogues as well as current activity for the future versions.

The Infrared Camera (IRC) is one of two focal-plane instruments on the AKARI satellite. It is designed for wide-field deep imaging and low-resolution spectroscopy in the near- to mid-infrared (1.8-26.5 micron) in the pointed observation mode of AKARI. The IRC is also operated in the survey mode to make an All-Sky Survey at 9 and 18 microns. The IRC is composed of three channels. The NIR channel (1.8-5.5 micron) employs a 512x412 InSb photodiode array, whereas both the MIR-S (4.6-13.4 micron) and MIR-L (12.6-26.5 micron) channels use 256x256 Si:As impurity band conduction (IBC) arrays. Each of the three channels has a field-ofview of approximately 10x10 arcmin., and they are operated simultaneously. The NIR and MIR-S channels share the same field-of-view by virtue of a beam splitter. The MIR-L observes the sky about 25 arcmin. away from the NIR/MIR-S field-of-view. The in-flight performance of the IRC has been confirmed to be in agreement with the pre-flight expectation. More than 4000 pointed observations dedicated for the IRC are successfully completed, and more than 90% of the sky are covered by the all-sky survey before the exhaustion of the Akari's cryogen. The focal-plane instruments are currently cooled by the mechanical cooler and only the NIR channel is still working properly. Brief introduction, in-flight performance and scientific highlights from the IRC cool mission, together with the result of performance test in the warm mission, are presented.

Infrared Camera (IRC) onboard AKARI satellite has carried out more than 4000 pointed observations during the phases 1 and 2, a significant amount of which were performed in the spectroscopic mode. In this paper, we investigate the properties of the spectroscopic data taken with MIR-S channel and propose a new data reduction procedure for slit-less spectroscopy of sources embedded in complicated diffuse background structures. The relative strengths of the 0th to 1st order light as well as the efficiency profiles of the 2nd order light are examined for various objects taken with MIR-S dispersers. The boundary shapes of the aperture mask are determined by using the spectroscopic data of uniform zodiacal emission. Based on these results, if the appropriate template spectra of zodiacal light emission and the diffuse background emission are prepared and the geometries of the diffuse structures are obtained by the imaging data, we can reproduce the slit-less spectroscopic patterns made by a uniform zodiacal emission and the diffuse background emission by a convolution of those template profiles. This technique enables us to obtain the spectra of infrared sources in highly complicated diffuse background and/or foreground structures, such as in the Galactic plane and in nearby galaxies.

AKARI is the first Japanese astronomical infrared satellite mission orbiting around the Earth in a sun-synchronous polar orbit at the altitude of 700 km. One of the major observation programs of the AKARI is an all-sky survey in the mid- to far-infrared spectral regions with 6 photometric bands. The mid-infrared part of the AKARI All-Sky Survey was carried out with the Infrared Camera (IRC) at the 9 and 18 µm bands with the sensitivity of about 50 and 120 mJy (5σ per scan), respectively. The spatial resolution is about 9.4" at both bands. AKARI mid-infrared (MIR) all-sky survey substantially improves the MIR dataset of the IRAS survey of two decades ago and provides a significant database for studies of various fields of astronomy ranging from star-formation and debris disk systems to cosmology. This paper describes the current status of the data reduction and the characteristics of the AKARI MIR all-sky survey data.

The ASTRO-F is an on-going infrared satellite mission covering 2-200 μm infrared wavelengths. Not only the all-sky survey in the mid-IR and far-IR, but also deep pointing observations are planned especially at 2-26 μm. In this paper, we focus on the near-infrared (NIR) channel of the infrared camera (IRC) on board ASTRO-F, and describe its design, and results of the imaging mode performance evaluation as a single component. The NIR consists of 4 lenses (Silicon - Silicon - Germanium - Silicon) with a 412 * 512 In:Sb detector. Three broad-band filters, and two spectroscopic elements are installed covering 2-5 μm wavelengths. Since the ASTRO-F telescope and the focal plane are cooled to 6 K, the evaluation of adjustment of the focus and the end-to-end test of the whole NIR camera assembly have to be done at cryogenic temperature. As a result of measurements, we found that the transverse magnification and distortion are well matched with the specification value (1 versus 1.017 and 1 %), while the chromatic aberration, point spread function, and encircled energy are slightly degraded from the specification (300 μm from 88 μm, > 1pixel from ~ 1pixel, 80 % encircled energy radius > 1pixel from ~ 1pixel). However, with these three measured values, in-flight simulations show the same quality as specification without degradation. In addition to the image quality, we also verified the ghost image generated from the optical element (1 % energy fraction to the original image) and the slightly narrowed field of view (10' * 9.5' from 10' * 10'). For the responsivity, the NIR shows expected response. Totally, the NIR imaging mode shows satisfactory results for the expected in-flight performance.

The MIR-L is the mid-IR (12-26 μ m) instrument for Japanese infrared astronomical satellite, the ASTRO-F. The instrument has 2 observing modes: a wide field imaging mode with a field of view of 10.7 × 10.2 arcmin 2 and a low resolution spectroscopic mode with a spectral resolution R = λ/Δλ about 20. The spectroscopic mode provides with not only slit-spectroscopy for extended sources but also slitless-spectroscopy for point sources. We describe here the design, manufacturing, and performance evaluation of the cryogenic optical system of the MIR-L. The concept of the optical system design is to realize wide field observations with a compact size. The instrument employs a refractive optics of 5 lenses (CsI - CsI - KRS-5 - CsI - KRS-5) with a 256×256 pixel Si:As IBC array detector, 3 filters, and 2 grisms. The refractive indices of CsI and KRS-5 at the operating temperature of about 6 K have ambiguities because of the difficulty of the measurements. We therefore designed the MIR-L optics with tolerances for the uncertainties of the indices. Since both CsI and KRS-5 have the fragility and the large thermal expansion, we designed a specialized mounting architecture to prevent from making damages and/or decentrations of the lenses at cryogenic temperatures under the serious vibration during the launch. As a result, the optical system of the MIR-L has passed both vibration and thermal cycle tests without damage and performance degradation, and achieved diffraction limited performance over its full wavelength range at the operating temperature.

MIR-L is a 12-26μm channel of Infrared Camera(IRC) onboard ASTRO-F. The camera employs a refractive optics which consists of 5 lenses (CsI - CsI - KRS-5 - CsI - KRS-5) and a large format Si:As IBC array detector (256 x 256 pixels). The design concept is to realize a wide field of view with a compact size. It has 2 observing modes: a wide field imaging with a field of view of 10.7 x 10.2arcmin2 or a pixel resolution of 2.5 x 2.4arcsec2/pixel in 3 bands (12.5-18μm, 14-26μm, 22-26μm), and low resolution spectroscopy with a spectral resolution R = λ/Δλ ≈40 in 2 bands 11-19μm,18-26μm). It also has a small slit to adapt for spectroscopic observations of extended sources. We describe the current design of the optics and the mounting architecture of MIR-L and evaluation of the optical performance at cryogenic temperatures.

An all-sky survey in two mid-infrared bands which cover wavelengths of 5-12um and 12-26μm with a spatial resolution of ~9" is planned to be performed with the Infrared Camera (IRC) on board the ASTRO-F infrared astronomical satellite. The expected detection limits for point sources are few tens mJy. The all-sky survey will provide the data with sensitivities more than one order of magnitude deeper and with spatial resolutions an order of magnitude higher than the Infrared Astronomical Satellite (IRAS) survey. The IRC is optimally designed for deep imaging in pointing observations. It employs 256x256 Si:As IBC infrared focal plane arrays (FPA) for the two mid-infrared channels. In order to make observations with the IRC during the survey mode of the ASTRO-F, a new operation method for the arrays has been developed - the scan mode operation. In the scan mode, only 256 pixels in a single row aligned in the cross-scan direction on the array are used as the scan detector and sampled every 44ms. Special cares have been made to stabilize the temperature of the array in the scan mode, which enables to achieve a low readout noise compatible with the imaging mode (~30 e-). The flux calibration method in the scan mode observation is also investigated. The performance of scan mode observations has been examined in computer simulations as well as in laboratory simulations by using the flight model camera and moving artificial point sources. In this paper we present the scan mode operation method of the array, the results of laboratory performance tests, the results of the computer simulation, and the expected performance of the IRC all-sky survey observations.

The Infrared Camera (IRC) is one of the focal-plane instruments on board the Japanese infrared astronomical space mission ASTRO-F. It will make wide-field deep imaging and low-resolution spectroscopic observations over a wide spectral range in the near- to mid-infrared (2-26um) in the pointed observation mode of the ASTRO-F. The IRC will also be operated in the survey mode and make an all-sky survey at mid-infrared wavelengths. It comprises three channels. The NIR channel (2-5um) employs a 512x412 InSb array, whereas both the MIR-S (5-12um) and the MIR-L (12-26um) channels use 256x256 Si:As impurity band conduction (IBC) arrays. The three channels will be operated simultaneously. All the channels have 10'x10' fields of view with nearly diffraction-limited spatial resolutions. The NIR and MIR-S share the same field of view, while the MIR-L will observe the sky about 25' away from the NIR/MIR-S field of view. The IRC will give us deep insights into the formation and evolution of galaxies, the properties of brown dwarfs, the evolution of planetary disks, the process of star-formation, the properties of the interstellar medium under various physical environments, as well as the nature and evolution of solar system objects. This paper summarizes the latest laboratory measurements as well as the expected performance of the IRC.

The infrared camera(IRC) onboard ASTRO-F is designed for wide-field imaging and spectroscopic observations at near- and mid-infrared wavelengths. The IRC consists of three channels; NIR, MIR-S and MIR-L, each of which covers wavelengths of 2-5, 5-12 and 12-26 micron, respectively. All channels adopt compact refractive optical designs. Large format array detectors (InSb 512x412 and Si:As IBC 256x256) are employed. Each channel has 10x10 arcmin wide FOV with diffraction-limited angular resolution of the 67cm telescope of ASTRO-F at wavelengths over 5 micron. A 6-position filter wheel is placed at the aperture stop in each channel, and has three band-pass filters, two grisms/prisms and a mask for dark current measurements. The 5 sigma sensitivity of one pointed observation is estimated to be 2, 11 and 62 micro-Jy at 4, 9, 20 micron bands, respectively. Because ASTRO-F is a low-earth orbiting satellite, the observing duration of each pointing is limited to 500 seconds. In addition to pointed observations, we plan to perform mid-infrared scanning observation. Fabrications of the flight-model of NIR, MIR-S, and the warm electronics have been mostly completed, while that of MIR-L is underway. The performance evaluation of the IRC in the first end-to-end test (including the satellite system) is presented.

We report on the extensive tests to characterize the performance of the infrared detector arrays for the Infrared Camera (IRC) on board the next Japanese infrared astronomical satellite, ASTRO-F. The ASTRO-Fwill be launched early 2004 and the IRC is one of the focal plane instruments to make observations in 2-26μm. For the near-infrared observations of 2-5μm, a 512x412 InSb array will be employed, while two 256x256 Si:As arrays will be used for the observations of 5-26μum in the IRC. Both arrays are manufactured by Raytheon. To maximize the advantage of the cooled telescope and extremely low background radiation conditions in space, the dark current and readout noise must be minimized. The heat dissipation of the arrays also has to be minimized. To meet these requirements and achieve the best performance of the arrays, we optimized the array driving clocks, the bias voltage, and the supply currents, and evaluated the temperature dependence of the performance. In particular, we found that the voltage between the gate and source of the FET of the multiplexer SBRC-189 had a strong dependence on temperature. This effect becomes a dominant source for the noise unless the temperature is kept within 20mK. We have achieved the readout noises of about 30e- and 40e- with the correlated double sampling for the flight model readout circuits of the InSb and Si:As arrays, respectively. These noises ensure that the background-limited performance can be achieved for the observations of IRC in the 4-26μm range in the current observing scheme. In addition, we are now planning to make scan mode observations by IRC. We have developed a new operation way of the arrays to achieve the stable response and low readout noise in the scanning operation for the first time. The IRC is now installed in the flight model cryostat and the first end-to-end test has just been completed. We report on the expected performance of the IRC together with the array test results.

The design overview and current development status of the Infrared Camera (IRC) onboard the Japanese infrared space mission, ASTRO-F (commonly called as the Infrared Imaging Surveyor, IRIS), are presented. The IRC is one of the focal plane instruments of ASTRO-F and will make imaging and low- resolution spectroscopy observations in the wide spectral range of the near- to mid-infrared of 2 - 26 micrometers . ASTRO-F will be brought into an IRAS-type sun-synchronous polar orbit. The IRC will be operated in the pointing mode, in which the telescope will be pointed at a fixed target position on the sky for about 10 minutes. The pointed observation may be scheduled up to three times per orbit. The IRC has three channels: NIR (2 - 5 micrometers ), MIR-S (5 - 12 micrometers ) and MIR-L (12 - 26 micrometers ). All of the three channels use refractive optics. Each channel has a field-of-view of 10' X 10' with nearly diffraction-limited spatial resolution. The NIR and MIR-S channels simultaneously observe the same field on the sky, while the MIR-L observes the sky about 20' away from the NIR/MIR-S position. State- of-the-art large format array detectors manufactured by Raytheon/IRCoE are employed for the IRC. The NIR channel uses a 512 X 412 InSb array, and 256 X 256 Si:As IBC arrays are used for the MIR channels. Fabrication of the proto-model has been completed and the preliminary performance test is under way.