This paper reports on a nested freeform Three Mirror Anastigmat (TMA) telescope designed for a 3U CubeSat, achieving a compact 1.5U form factor with a focal length of 500mm, F/4.6. Capable of near-diffraction-limited performance in a 0.37°x0.42° field of view, it provides 5m Ground Sampling Resolution in Low Earth Orbit. The paper explores two housing options: one for additive manufacturing (AM) and the other for conventional machining (CM), aiming to determine the optimal approach for creating an AM-based optical system housing suitable for space. The AM option offers lightweighting opportunities and enhanced structural integrity.
The mirrors, manufactured in RSA 443 with Nickel Phosphorus plating, alongside the AM material, AlSi40, are discussed for their homogeneous coefficient of thermal expansion crucial for orbital conditions. The paper reports on the AM process, system metrology, and high precision finishing through Ion Beam Figuring.
Here, we report the design, manufacturing, and characterization of x-ray optical components for the cavity-based x-ray free-electron laser (CBXFEL) cavity, in the framework of the CBXFEL R&D collaborative project of Argonne National Laboratory, SLAC National Accelerator Laboratory, and SPring-8. The optical components include high-reflectivity diamond crystal mirrors, reflecting and output coupling diamond drumhead crystal with thin membranes, focusing beryllium refractive lenses, and channel-cut Si crystal monochromators. All the designed optical components have been fully characterized at the Advanced Photon Source to demonstrate their desired performance for the CBXFEL cavity.
A cavity-based x-ray free-electron laser (CBXFEL) is a possible future direction in the development of fully coherent x-ray sources. One of the challenges of a CBXFEL is the requirement of the three-dimensional overlapping of the μm-sized electron beam with the circulating μm-sized x-ray beam in an x-ray cavity of tens or hundreds of meters long. In the framework of the CBXFEL R&D collaborative project of Argonne National Laboratory, SLAC National Accelerator Laboratory, and Spring-8, we present here the development of an x-ray diagnostics system for an accurate alignment of x-ray beams in the CBXFEL cavity. All the designed diagnostics components have been fully characterized at the Advanced Photon Source to demonstrate a sub-μrad-angular and μm-spatial alignment accuracy for the CBXFEL cavity.
We present fabrication and characterization of ultra-thin with ∼15-25 µm thick (300 µm in diameter) diamond single-crystal membranes for various applications in synchrotron radiation sources, x-ray free-electron lasers (XFELs), and XFEL oscillators. Ultra-thin diamond single-crystal membranes are fabricated using laser ablation techniques with ultra-short (femtosecond) laser pulses. Here, we report optimizing the laser ablation parameters such as fluence, power, repetition rate, pulse length, and wavelengths. The crystal quality of the ultra-thin diamond membranes has been characterized by x-ray rocking curve imaging (RCI) of the crystal before and after laser ablation and subsequent high-temperature annealing.
W / B4C multilayer (ML) mirrors with varying periodicities ( d ) = 1.6 to 5.4 nm are tested for rapid thermal and temporal stability, which are required for space-based x-ray telescopes for astronomy. The aging effects on the structural parameters over a period of 2 years are assessed through hard x-ray reflectivity (HXR) measurements. Multiwavelength performance of ML mirrors is studied over thermal cycling from −40 ° C to +50 ° C for 1, 3, and 10 days, which simulate the expected temperature variation in the low-earth orbit. The structural parameters of all samples remained nearly constant over the first 2 years. It is observed that the short-period MLs develop a contamination layer over time. Rapid thermal cycling results indicate no change in HXR for all ML mirrors. However, at soft x-rays, there is a reduction in reflectivity after thermal cycling. The variations in optical performance at hard and soft x-ray energies after thermal cycling are due to variation in interface roughness at different spatial frequencies.
We present fabrication and structural analysis of two different multilayer grating structures. W/B4C based lamellar multilayer grating (LMG) was studied for high resolution monochomator application near soft x-ray region (~1.5 keV). Whereas NbC/Si based multilayer phase-shift reflector (MPR) was studied for high reflection at normal incidence near Si L-edge (~99 eV) and simultaneously to suppress the unwanted vacuum ultraviolet / infrared radiation. The grating patterns of different periods down to D = 10 micron were fabricated on Si substrates by using photolithography, and multilayers (MLs) of different periodicity (d = 10 to 2 nm) and number of layer pairs (15 to 100) were coated using sputtering techniques by optimizing the process parameters. The LMG and MPR samples are characterized by x-ray reflectivity (XRR) and atomic force microscopy (AFM) measurements. XRR results show successive higher order Bragg peaks that reveal a well-defined vertical periodic structure in LMG, MPR and ML structures. The lateral periodicity of the grating and depth of the rectangular groves were analyzed using AFM. The AFM results show good quality of lateral periodic structures in terms of groove profile. The effect of the process parameters on the microstructure (both on vertical and lateral patterns) of ML, LMG and MPR were analyzed.
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