The XACT facility has been designed to be versatile and easy to use both in the testing and calibration of instrumentation at the sub-system level (filters, detectors, optics) as well as in the calibration of fully integrated short focal length X-ray mirrors/telescopes.

A document providing more detailed description of XACT is available here.

The XACT facility of the INAF – Osservatorio Astronomico di Palermo ”G.S. Vaiana” (OAPA) was established in the early 1990s to participate in the development and calibration of the UV/Ion shields of the High Resolution Camera (HRC) of the, still operational, Chandra X-ray Observatory. Since then the facility has been actively used in several research projects including long-term monitoring of EPIC filters, calibration of NASA SOLAR-B X-ray mirror, of Chinese CHANG-E X-ray detector, of Polish SPHINX solar spectrograph as well as supporting laboratory programmes in novel X-ray optics and detectors. The non-staff as well as specific costs of those activities are funded by project grants and contracts to INAF/OAPA, while staff efforts and general costs are covered by INAF. Associated travel costs of visitors have been covered by the respective host institutes. The facility is operative for 220 working days per year, mostly for internal use. No formal record of accesses is available since it was not required by internal regulations. A recording scheme will be activated for dealing with proposed TA.

A view of the 35m long XACT OAPA facility

The main components of the XACT facility include: 1) A 35-meter long vacuum beam-line including an X-ray source small chamber, a monochromator chamber 0.8-meter diameter and 1-meter height, a big chamber 3.5-meter long and 2-meter diameter to accommodate large size experiments, and a detector test chamber 1-meter long and 1-meter diameter opening inside a class 1000 clean-room. The diameter of the tubes increases from the source end (150 mm) to the telescope chamber to allow a full area illumination of 800 mm diameter, minimizing the volume and the internal surface of the pipe. The vacuum pumping system is entirely based on magnetic levitation turbo-molecular pumps, and on oil-free rotary pre-vacuum and back-up pumps. A minimum pressure of 5 x 10−8 mbar can be achieved, while normal operation is in the 10−7 mbar scale; 2) Three electron impact micro-focus X-ray sources, providing characteristic lines and bremsstrahlung continuum soft X-ray photons in the energy range 0.1-20 keV. The sources are very efficient, and depending on the anode material and operating parameters, they can produce X-ray fluxes in full illumination ranging between 100 and 50000 photons s−1 cm−2 at about 34 meters distance from the source; 3) X-ray detectors (proportional counters, MCP detectors, and solid state detectors) and monochromators (transmission grating, fixed exit double Bragg diffraction) covering the energy range 0.1-30 keV; 4) A large number of vacuum compatible micro-positioning systems including an alt-azimuth mount for testing grazing incidence X-ray optics. 5) A vacuum UV beam-line attached on a side port of the detector test chamber of the main beam-line, equipped with sources, monochromator and detectors operating in the wavelength range 10-3000 A.
A suite of software applications, with user-friendly interfaces, based on the NI Labview™ software platform allows the XACT full remote control of the operations. A well-equipped mechanical shop including a CNC lathe and milling machines, and support facilities such as a class 1000 clean room, class 100 clean benches, chemical hub, optical microscope, etc. are also available and will be part of the XACT/OAPA participation to the TA offer.

X-Ray beam-line 35m long, high vacuum pumpin system fully based on extra-clean magnetic levitation turbo-molecular pumps