Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Gigantic mirror for X-radiation in outer space

28.09.2010
New PTB instrument measures the quality of the mirrors for the X-ray telescope IXO

It is to become the largest X-ray telescope ever: The International X-Ray Observatory (IXO), which has been planned in a cooperation between NASA, ESA and Japan's Aerospace Exploration Agency JAXA, will be launched into space in 2021 and provide the world with brand new information about black holes and, thus, about the origin of the universe.

Its dimensions are gigantic: The surface of the mirror alone, which is to capture, for example, the cosmic X-radiation of black holes, will be 1300 m2 in size. It will consist of commercially available silicon wafers with pores of a few millimetres underneath. The quality of these "hidden" surfaces will be tested at the Physikalisch-Technische Bundesanstalt (PTB) with a monochromatic X-ray pencil beam. The new measuring device has been installed at PTB's synchrotron radiation laboratory at BESSY II in Berlin-Adlershof.

eROSITA will do the preliminary work. The German-Russian experiment under the auspices of the Max Planck Institute for Extraterrestrial Physics will be launched into space in 2013. With the aid of a bundle of seven X-ray telescopes, eROSITA will search the whole sky for a specific kind of black hole: supermassive black holes which developed at the dawn of the universe - probably even before the development of the first stars.

Scientists expect that - among other things - approximately three million new black holes will be found with this mission. This will, for the first time, allow a complete overview of the formation and development of supermassive black holes to be given. IXO will then be responsible for their systematic investigation. In addition, the new space telescope is to provide much new information about neutron stars and stellar black holes, the second type of black hole which develops when especially massive stars explode. Due to the fact that such a venture is extremely expensive, in 2008 the space agencies of the USA, of Europe and Japan decided to realize this joint project from then on instead of three individual solutions.

IXO can capture the X-radiation of very distant black holes, because this kind of radiation penetrates - in an unhindered way - cosmic dust, which is the most frequently occurring impediment on the way. For that purpose, the mirror in the telescope must be very large, but at the same time light enough. IXO will have one single mirror with a collection surface of approx. 3 m², a focal length of 20 m and an angular resolution of less than 5 arc seconds. Due to the required grazing radiation incidence, the whole surface of the mirror must be approx. 1300 m². To construct this large surface in a stable and, at the same time, light way, the underneath of commercially available, highly polished silicon wafers will be provided with ribs to allow the wafers to be stacked in rigid blocks. Through this, pores with a cross-section of approximately 1 mm² are formed in which the radiation is reflected at the surface of the respective lower wafer. With respect to tangent errors and roughness, the quality of these "hidden" surfaces cannot be investigated as usual from above, but must be determined in the intended application geometry with X-ray reflection at grazing incident angles of approx. 1°. To investigate the reflecting surface of single pores, an X-ray pencil beam is required.

At the "X-ray pencil beam facility" (XPBF) at PTB's synchrotron radiation laboratory at BESSY II, which has recently been extended within the scope of a research cooperation with ESA, a monochromatic pencil beam with a typical diameter of 50 µm and a divergency of less than one arc second is now available for this purpose. It will characterize the X-ray lens systems for IXO at three different photon energies, i.e. at 1 keV, 2.8 keV and 7.6 keV. The lens systems can be adjusted or turned with a hexapod in vacuum with reproducibilities of 2 µm or below 1", respectively. The direct beam and the reflected beam are registered with a spatial resolving detector based on CCD at a distance of 5 m or 20 m from the lens system. For the last-mentioned distance, which corresponds to the intended focal length of IXO, a vertical movement of the CCD detector by more than 2 m has been implemented. First test measurements at this distance were already performed in May 2010, complete commissioning of the extended XPBF is planned for the beginning of November 2010.

Contact
Michael Krumrey, PTB Working Group 7.11 X-ray Radiometry,
phone: +49 (0)30 6392-5085,
E-mail: michael.krumrey@ptb.de
Current scientific publication
Krumrey, M.; Cibik, L.; Müller, P.; Bavdaz, M.; Wille, E.; Ackermann, M.; Collon, M. J.: X-ray pencil beam facility for optics characterization. Proc. SPIE 7732, 77324O (2010)

Michael Krumrey | EurekAlert!
Further information:
http://www.ptb.de

More articles from Physics and Astronomy:

nachricht New NASA study improves search for habitable worlds
20.10.2017 | NASA/Goddard Space Flight Center

nachricht Physics boosts artificial intelligence methods
19.10.2017 | California Institute of Technology

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>