meter. When medical X-rays are being produced, a thin metallic sheet is placed between the emitter and the target, effectively filtering out the lower energy (soft) X-rays. The resultant X-ray is said to be
. The frequency of hard X-rays is higher than that of soft X-rays, and the wavelength is shorter. Hard X-rays overlap the range of "long"-wavelength (lower energy)
, however the distinction between the two terms depends on the source of the radiation, not its wavelength: X-ray
.
X-ray K-series spectral line wavelengths (nm) for some common target materials
More on [ X-ray ]
Astrophysics :: Physics
Space :: Technology
NPR Topics: SpaceAstronomers See A New Class of Black Hole Fri, 03 Jul 2009 13:00:00 -0400
Scientists say X-ray data collected by the European Space Agency's XMM-Newton spacecraft show evidence of a new type of black hole in a galaxy about 290 million light years from Earth. Astronomer Sean Farrell explains what the discovery might tell us about galaxy evolution.
Salty Sea May Lurk Under Saturn Moon Thu, 25 Jun 2009 13:00:00 -0400
Salty ice grains inside in Saturn's outer ring point to a possible underground ocean on the moon Enceladus.
Breaking Ground On The First Spaceport Sat, 20 Jun 2009 12:13:00 -0400
Out in the wilds of New Mexico, they're marketing a new kind of commercial space — as in, outer space. On Friday, New Mexico broke ground on what's billed as the world's first commercial spaceport.
Summer Sky Highlights What's Missing Fri, 19 Jun 2009 13:00:00 -0400
This season's astronomical highlights are about what won't be visible in the night sky. Astronomer Paul Rao discusses what he describes as "the eclipse of the century," Jupiter's mysterious missing moons, the vanishing rings of Saturn and the forthcoming Perseid meteor shower.
NASA Moon Missions To Search For Water Thu, 18 Jun 2009 00:48:00 -0400
A rocket is scheduled to blast off for the moon Thursday afternoon carrying two probes that will gather data to prepare for possible future manned missions. One probe will map the moon, and the other will search for water ice.
NASA To Launch Two Moon Missions Wed, 17 Jun 2009 16:00:00 -0400
NASA will launch Thursday two missions to the moon. One spacecraft will orbit the moon and create an unprecedented high-resolution map of the lunar surface. The other mission will send a spent rocket part on a collision course with a permanently shadowed lunar crater.
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ASCA Guest Observer Facility - About ASCA, services, what's new, data processing, timelines and mission, gallery, and related sites.
Meta Description: [ The primary responsibility of the
ASCA Guest Observer Facility is to enable U.S.
astronomers to make the best use of the ASCA x-ray mission,
in close collaboration with the Japanese ASCA team. ]
Chandra X-ray Observatory - Orbiting observatory that opens a window for the most detailed X-ray view of the universe.
Chandra X-ray Observatory - Public information and education, and scientific user support.
Chandra X-ray Observatory - Data analysis, instruments and calibration, links, target and scheduling, users, newsletters.
Chandra X-ray Observatory - Part of NASA's collection of space observatories. This one specializes in x-ray technology.
MAXIM - MicroArcsecond X-Ray Imaging Mission - The vision, mission, the science, pathfinder, resource, documents, what's new, and contacts.
Meta Description: [ The MicroArcsecond X-ray Imaging Mission Web Site ]
500
Strasbourg Observatory - News, responsibilities, activities, document, and links.
The USA Experiment - Introduction, news, technical specifications, gallery, observations, data analysis, publications, and links.
The XMM Satellite School Page - Information for teachers, x-ray astronomy, telescopes, images, spacecraft, astrophysics, and the laboratory.
X-ray Data Reveal Black Holes Galore - Article by Ron Cowen.
Meta Description: [ Using a sensitive, new X-ray telescope, astronomers have identified the origin of the high-energy part of the X-ray background and found that supermassive black holes at the cores of galaxies are far more numerous than visible-light surveys indicate. ]
XMM-Newton Science Operations Centre - News, observer's information, scheduling, support, software and calibration, data access, science, and news.
