The Einstein Probe mission, due to launch in late 2022, will study time-domain astrophysics and monitor variable objects. It aims to observe x-ray counterparts of gravitational wave sources and high-redshift gamma ray bursts. Developed and built by the Chinese Academy of Sciences, Einstein Probe will use two types of telescope: the WideField X-ray Telescope (WXT) and the Follow-Up X-ray Telescope (FXT). The FXT will perform follow-up observations of sources discovered by the WXT, and will observe in the energy range of 0.5 to 8 keV. The performance aim of the FXT – the point spread function half-energy width (PSF HEW) – is <20 arcseconds (on-axis at 1.49 keV). The Max-Planck Institute for Extraterrestrial Physics (MPE) is producing and integrating the x-ray straylight baffle for the FXT, as well as testing and calibrating the different models of the FXT x-ray optic. Production of the structural-thermal model (STM) for Einstein Probe FXT began in 2019. The STM mirror module, produced by Media Lario, has been tested at MPE’s PANTER x-ray test facility. Following this acceptance test, further x-ray tests have been performed at PANTER after each of the subsequent stages: the mounting of the x-ray baffle, the shock and vibration test, and the thermal cycling test. The x-ray performance of the FXT STM is documented at each stage and the results of each test are presented in this paper.
The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a Chinese – French satellite mission due to be launched in the summer of 2022. It is composed of four instruments: ECLAIRs, for detecting X-ray and gamma-ray transients (4-250 keV); GRM, a gamma-ray spectrometer (15 keV-5 MeV); VT, a visible telescope and the Microchannel X-ray Telescope (MXT). The MXT’s main goal is to precisely localize, and spectrally characterize X-ray afterglows of Gamma-Ray Bursts. The MXT is a narrow-field-optimised lobster eye X-ray focusing telescope comprising an array of 25 square Micro Pore Optics (MPOs), with a detectorlimited field of view of ∼1 square degree, working in the energy band 0.2-10 keV. The SVOM qualification model (QM) MXT optic (MOP) was designed and built at the University of Leicester, and is the first complete, lobster eye optic to be X-ray tested. We present results from the PANTER facility (MPE), where a full calibration of the QM MOP was carried out. The response of the optic was studied at seven energies from C-K to Cu-K, and the effective area at multiple off-axis angles at each energy was measured. The focal length of the MOP was confirmed and the PSF was studied on and off-axis. In addition, we present details of the modelling and analysis, which was used to calculate the results from the test campaign. The effective area and PSF are in good agreement with the modelling, indicating that the optic is performing as expected.
High-resolution (R = λ/Δλ >2000) x-ray absorption and emission line spectroscopy in the soft x-ray band is a crucial diagnostic for the exploration of the properties of ubiquitous warm and hot plasmas and their dynamics in the cosmic web, galaxy clusters, galaxy halos, intragalactic space, and star atmospheres. Soft x-ray grating spectroscopy with R > 10,000 has been demonstrated with critical-angle transmission (CAT) gratings. CAT gratings combine the relaxed alignment and temperature tolerances and low mass of transmission gratings with high diffraction efficiency blazed in high orders. They are an enabling technology for the proposed Arcus grating explorer and were selected for the Lynx design reference mission grating spectrometer instrument. Both Arcus and Lynx require the manufacture of hundreds to perhaps ≈ 2000 large-area CAT gratings. We are developing new patterning and fabrication process sequences that are conducive to large-format volume processing on stateof-the-art 200 mm wafer tools. Recent x-ray tests on 200 nm-period gratings patterned using e-beam-written masks and 4x projection lithography in conjunction with silicon pore focusing optics demonstrated R ≈ 104 at 1.49 keV. Extending the grating depth from 4 μm to 6 μm is predicted to lead to significant improvements in diffraction efficiency and is part of our current efforts using a combination of deep reactive-ion etching and wet etching in KOH solution. We describe our recent progress in grating fabrication and report our latest diffraction efficiency and modeling results.
The PANTER X-ray test facility of the Max Planck Institute for Extraterrestrial Physics (MPE) has over 40 years of heritage in testing and calibrating x-ray optics. Having contributed to missions such as XMM-Newton, Chandra, and eROSITA, the facility measures the performance of x-ray optic technologies that will enable future x-ray telescopes to be realised. Over the last year, PANTER has been testing the latest developments in silicon pore optics for ESA’s ATHENA mission, as well as full-shell eROSITA-like optics for the CAS/ESA/MPE Einstein Probe mission. For ATHENA, complete mirror modules for the outer radius of the telescope have been tested. The latest developments in the optics for the mid-radius of the telescope, including the first confocal mirror module, have been measured for performance. The paper will provide an overview of the most recent testing carried out at PANTER, and the alignment and measurement techniques used.
Currently for the European Space Agency (ESA) ATHENA [1,2] mission Silicon Pore Optic (SPO) [3-8] Mirror Modules (MM) with a focal length of f = 12 m, are being developed and tested. The SPO MMs are also the baseline optic for the NASA medium explorer high-resolution spectroscopy mission Arcus [9-10] with f = 12 m that is currently undergoing a phase A study. SPOs are currently being tested at both the PTB laboratory of the BESSY synchrotron facility in Berlin using an X-ray pencil beam and the PANTER X-ray test facility in Neuried of the Max-Planck-Institut für extraterrestrische Physik, Garching using a long vacuum beamline (distance source to optic ~120 m). The different types of measurements performed at PANTER to characterise the ATHENA and Arcus optics will be discussed. This will be done on the level of an X-ray optical unit (XOU) composed of both a primary and secondary High Performance Optic (HPO) stack, a mirror module (MM) composed of two XOUs, small (<4 MMs) and large (< 25 MM) petals, and the complete integrated optic Athena (700-1000 MMs) and Arcus (4 petals each with 38 MMs). The main set of tests that are currently done at PANTER make full use the possibility to fully-illuminate single XOUs, MMs, and petals to determine their optical characteristics such as the half energy width of the point spread function as well as the effective area and the vignetting function at different energies. To ensure that the measurements, that are required to demonstrate the performance of ATHENA, are possible, a description of recent and upcoming upgrades to the PANTER X-ray test facility will be given. Finally, a status update on the progress on designing the new facility to be used to test and calibrate the complete ATHENA mirror will be presented.
Detection of explosives by ion mobility spectroscopy has become common in recent years. We demonstrate explosive
detection with a novel Laser Ion Mobility Spectrometer (LIMS) developed at EADS Innovation Works. A Laser
operating at 266nm was used for the two-photon ionisation of dopant and calibrant substances. Quantitative
measurements of trace residues of explosives have been performed to quantify the sensitivity of the LIMS system.
Findings demonstrate the suitability of this technique as a screening tool for explosive compounds.
Trace detection of toxic industrial compounds has been investigated with the help of a laser ion mobility spectrometer
(LIMS). The LIMS was equipped with a tuneable UV laser source for enabling two-photon ionization of the analyte
gases and an ion drift tube for the measurement of the ion mobility. Different aromatic and aliphatic hydrocarbons as
well as amines were investigated. We find that the first class of molecules can be well ionized due to the delocalization
of their valence electron shells and the second due to the presence of non-bonding electrons in lone-pair orbitals.
Selectivity of detection is attained on the basis of molecule-specific photo-ionization and drift time spectra. Ion currents
were found to scale linearly with the substance concentration over several orders of magnitude down to the detection
limits in the ppt range. As besides toxic industrial compounds, similar electron configurations also occur in illicit drugs,
toxins and pharmaceutical substances, LIMS can be applied in a variety of fields ranging from environmental analysis,
air pollution monitoring, drug detection and chemical process monitoring.
A novel backscatter-lidar imaging method of visualization of air movement in the atmosphere is discussed in the paper.
The method is based on the particle image velocimetry (PIV) principle, namely: pairs of image of laser illuminated thin
atmospheric layers are recorded by CCD camera and then are cross correlated to obtain velocity information from these
records. Both the way of computer simulation of atmospheric version of PIV technique and the first concept proof
experiments are described in the paper. It is proposed that the method can find an application for visualization of wake
vortices arising behind large aircrafts.