XL-Calibur Image Gallery: Instruments

Detector

XL-Calibur polarimeter diagram. X-rays are focused by the mirrors, enter through the collimator and encounter the Be scattering rod. CZT detectors around the perimeter of the scattering rod measure the polarization while the CZT detector at the base of the rod functions as a source imager. The Faraday cage shields the instrument from electronic noise external to the detector.

Housing around the polarimeter for XL-Calibur. Incoming X-rays enter through the collimator and detected by the polarimeter (see above). The detector is surrounded by Be₄GeO₁₂ (BGO) crystals with photomultipliers which serve as an anticoincidence detector, allowing events entering the instrument from directions other than the pointed direction of the telescope to be rejected.

Photograph of the Be scattering rod, CZT detectors, and electronics.

Photograph of the shielding around the detector, including the photomultiplier tubes (PMTs) which detect anti-coincidence events, the tungsten collimator, and the rolling mechanism to slowly rotate the entire dtector assembly.

Photograph of the XL-Calibur polarimeter, partially assembled. The copper colored element is the Faraday cage surrounding the Be scattering rod and CZT detectors, and the base plate with the back plate of BGO anti-coincidence detectors and photomultipliers are included, but the other surrounding BGO crystals, photomultipliers, and the tungsten collimator have not yet been mounted (but appear in the background on the rolling cart).

Mirrors

XL-Calibur telescope design.

The FFAST X-ray mirror assembly.

The truss for XL-Calibur with the nested mirror assembly facing out. The truss is made of lightweight material, but designed to be strong enough to withstand high-g stress encountered when landing at the end of the mission, and maintain stability and shape during the temperature variations from the ground through to the stratosphere. The mirror consists of a set of nested conical shells of coated metal designed to focus incoming hard X-rays using grazing incidence reflection. The focal point of the mirror is the detector at the opposite end of the assembly, located 12 m from the mirror.

The mirror end of the XL-Calibur telescope truss at Esrange Space Center, May 2022. The large white tube is the off-axis star tracker, which allows precision tracking when the telescope is pointed at stratospheric clouds or tilted to high elevation targets (i.e. looking up through the balloon).

Gondola

XL-Calibur diagram, including the entire gondola, steering systems, mirrors, truss, and supporting components such as electronics and solar panels.

Movies

A walkaround of the XL-Calibur x-ray telescope on June 22, 2022 after assembly at the Esrange Space Center in Kiruna, Sweden. The movie starts at the mirror end and shows all three star trackers, the truss, gondola, solar panels, and the polarimetry detector and its shielding at the back end (48 s; 640 x 360 MP4 (4.1 MB); 1920 x 1080 MP4 (27.8 MB); YouTube ).