Gamma ray measurements. Medical search. Frequent questions

In addition, they have detected immensely powerful gamma-ray bursts (GRBs) that appear to come from sources in deep space. (newworldencyclopedia.org)
Detectors aboard the Vela satellite series, designed to detect flashes of gamma rays from nuclear bomb blasts, began to record bursts of gamma rays not from the vicinity of the Earth but from deep space. (newworldencyclopedia.org)
It predominantly studied X-rays, but also observed gamma-ray bursts. (newworldencyclopedia.org)
Depending on their initial parameters, e.g., initial mass, metalicity, mass loss, and rotation, different kinds of supernovae are the result: normal core collapse supernovae, collapsar-powered supernovae like gamma-ray bursts, or even pair-instability supernovae. (cern.ch)
X-ray bursts and the rp-process play a central role in this context. (cern.ch)
It is an expansion of the AAVSO International Gamma-Ray Burst Network which had great success in discovering and observing the optical afterglows of gamma-ray bursts (GRBs). (aavso.org)
This database table comprises the gamma-ray bursts detected by the BATSE instrument on the Compton Gamma-Ray Observatory (CGRO). (nasa.gov)
It includes the gamma-ray bursts from the BATSE 4B Catalog (triggers 105 through 5586, observed between April 19, 1991, and August 29, 1996) as well as a large number of triggered bursts since the publication of the BATSE 4B Catalog. (nasa.gov)
in 'Gamma-Ray Bursts: the Fourth Huntsville Symposium (IAP No. 428)', ed. (nasa.gov)
This database table contains values for T90 and T50, quantities related to burst duration, for 1234 gamma-ray bursts that triggered the BATSE LAD detectors between April 1991 and 29 August 1996. (nasa.gov)
Gamma-rays from cosmological gamma-ray sources, primarily blazars but also gamma-ray bursts, interact with the extragalactic background light (EBL) photons, and are absorbed. (cern.ch)
A new nano satellite mission, called 'Firefly,' sponsored by the National Science Foundation (NSF) and led by NASA's Goddard Space Flight Center in Greenbelt, Md. will explore the relationship between lightning and these sudden bursts, called Terrestrial Gamma Ray Flashes (TGFs). (sciencedaily.com)
Gamma-Ray Bursts. (aus.edu)
His area of expertise is cosmic gamma-ray sources (the galactic center, accretion disks, bursts, etc.), but he has also written many articles and several books on issues related to science, education and Islam, such as 'Islamic Astronomy' (the crescent observation problem, the Islamic calendar, etc. (aus.edu)
Why do some gamma-ray bursts last hours? (cerncourier.com)
Three unusually long-lasting stellar explosions discovered by NASA's Swift satellite represent a new class of gamma-ray bursts (GRBs). (cerncourier.com)
An artist's impression of two stars of very different size creating gamma-ray bursts (GRBs). (cerncourier.com)
While most of the thousands of GRBs observed so far fall into these two categories, there are also peculiar sub-energetic bursts ( CERN Courier September 2004 p13 ) and unrelated gamma-ray events that arise from the tidal disruption of a star by a supermassive black hole ( CERN Courier July/August 2011 p14 ). (cerncourier.com)
If more gamma-ray bursts are detected from gravitational wave events, they will offer a promising new method of measuring cosmic distances and the expansion of the universe. (eurekalert.org)

The energy spectrum of gamma rays can be used to identify the decaying radionuclides using gamma spectroscopy. (wikipedia.org)
ISO 19581 specifies a screening test method to quantify rapidly the activity concentration of gamma-emitting radionuclides, such as 131 I, 132 Te, 134 Cs and 137 Cs, in solid or liquid test samples using gamma-ray spectrometry with lower resolution scintillation detectors as compared with the HPGe detectors (see IEC 61563). (iso.org)
The test method applies to the measurement of gamma-emitting radionuclides such as 131 I, 134 Cs and 137 Cs. (iso.org)
Following the accident, measurements of food radioactivity levels, especially of 137 Cs, became more readily available because of the Japanese government's rapid establishment of a food monitoring campaign to detect radionuclides. (nature.com)
Surface water measurements for radionuclides at the HISS showed the presence of total uranium ranging from bkg to 5 pCi/L, Th-230 ranging from 0.1 to 0.9 pCi/L, and Ra-226 ranging from 0.1 to 0.3 pCi/L ( Tables 1 , 2 ). (cdc.gov)
1.1 This test method covers the measurement of gamma-ray emitting radionuclides in water by means of gamma-ray spectrometry. (astm.org)
In addition to the quantitative measurement of gamma radioactivity, gamma spectrometry can be used for the identification of specific gamma emitters in a mixture of radionuclides. (astm.org)
The results of gamma-ray spectrometry confirmed sediments as a useful indicator of radionuclides, with activity concentrations above the MDA levels for all reported radionuclides and samples, except for one site. (lu.se)
Gamma-ray spectrometry measurements on the samples can provide information on local elevated levels of anthropogenic radionuclides and add information to the sources of the sediment itself. (lu.se)

The shipboard physical properties program at Site U1385 included high-resolution nondestructive measurements of gamma ray attenuation (GRA) bulk density, magnetic susceptibility (loop sensor), P -wave velocity, and natural gamma radiation (NGR) on whole-round core sections. (iodp.org)
Astrophysicists developed an ingenious work-around method - measuring the EBL indirectly through measuring the attenuation of very high-energy gamma rays from distant blazars. (astronomy.com)
Thus, the gamma-ray attenuation spectrum from farther distant blazars reveals how the EBL looked at earlier eras. (astronomy.com)
Bulk densities and porosities were obtained with gamma ray attenuation equipment. (epa.gov)

5.2 Many soil characterization plans for radionuclide constituents utilize gamma-ray spectrometry measurements of soil to quantify a number of possible gamma emitting analytes. (astm.org)

However, there are other rare natural sources, such as terrestrial gamma-ray flashes, which produce gamma rays from electron action upon the nucleus. (wikipedia.org)
Identifying the source of terrestrial gamma ray flashes would be a great step toward fully understanding the physics behind lightning and its effect on the Earth's atmosphere. (sciencedaily.com)

Long before scientists could detect gamma rays from cosmic sources, they had suspected that the universe may be producing photons in this energy range. (newworldencyclopedia.org)
In 1961, the Explorer 11 satellite carried the first space-based gamma-ray telescope, which detected less than 100 cosmic gamma-ray photons. (newworldencyclopedia.org)
[1] As these photons seemed to come from all directions, they suggested the presence of a uniform "gamma-ray background" in the universe. (newworldencyclopedia.org)
At energies above 100 TeV, gamma-rays suffer strong absorption from pair production with photons from the cosmic microwave background radiation that strongly reduces their mean free path [ 3 ]. (hindawi.com)
The H.E.S.S. telescope array is used to study cosmic source that radiate very-high-energy (VHE) gamma rays, electromagnetic radiation whose photons are 1.000.000.000.000 times more energetic than the visible light that we see with our eyes. (mpg.de)
This figure illustrates how energetic gamma rays (dashed lines) from a distant blazar strike photons of extragalactic background light (wavy lines) and produce pairs of electrons and positrons. (astronomy.com)
Different energies of the highest-energy gamma rays are waylaid by different energies of EBL photons. (astronomy.com)
Thus, measuring how much gamma rays of different energies are attenuated or weakened from blazars at different distances from Earth indirectly gives a measurement of how many EBL photons of different wavelengths exist along the line of sight from blazar to Earth over those different distances. (astronomy.com)
Gamma rays consist of high energy photons with energies above about 100 keV . (wikidoc.org)
X-ray photons are generated by energetic electron processes, gamma rays by transitions within atomic nuclei. (wikidoc.org)
The photoelectric effect is the dominant energy transfer mechanism for x-ray and gamma ray photons with energies below 50 keV (thousand electron volts ), but it is much less important at higher energies. (wikidoc.org)
The interaction creates neutral pion that quickly decays into two gamma-ray photons (hadronic process). (scitechdaily.com)
Gamma radiation and x-rays are electromagnetic radiation (ie, photons) of very short wavelength that can penetrate deeply into tissue (many centimeters). (msdmanuals.com)

Recent developments in in situ gamma-ray spectrometry provide a novel and effective method for monitoring anthropogenic radionuclide concentrations and distributions within these coastal environments. (stir.ac.uk)
Methods of localizing and quantifying radionuclide sources and deposition by means of in situ gamma spectrometry. (lu.se)
Radiation and radionuclide measurements at radiological and nuclear emergencies. (lu.se)

and sediment accretion rates were also mapped directly through in situ measurements. (stir.ac.uk)
3) a database of 402 in situ measurements of gamma emissions, and (4) two databases of housing characteristics. (cdc.gov)
The findings suggest that fault mapping and in situ gamma ray measurements, coupled with analysis of foundation types and delineation of hot spots, may be used to prioritize areas for radon screening. (cdc.gov)

Artist's image of the Compton Gamma Ray Observatory. (newworldencyclopedia.org)
The Compton Gamma-Ray Observatory (CGRO) was designed to take advantage of the major advances in detector technology during the 1980s, and it was launched in 1991. (newworldencyclopedia.org)
NASA's Compton Gamma Ray Observatory (CGRO) first discovered TGFs in the 1990s. (sciencedaily.com)

Diffuse nucleosynthesis is studied through 26Al, 60Fe, and positron annihilation gamma-ray measurements. (cern.ch)
Gamma rays (denoted as γ ) are a form of electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions, such as electron-positron annihilation or radioactive decay . (wikidoc.org)

Due to this, there are several dedicated instruments, both ground or space based, performing a continuous survey of the Universe characterizing gamma-ray sources, for example, the Fermi Gamma-Ray Space Telescope and the imaging atmospheric Cherenkov telescopes HESS, MAGIC, VERITAS, and FACT. (hindawi.com)
WASHINGTON -- Astronomers using NASA's Swift satellite and Fermi Gamma-ray Space Telescope are seeing frequent blasts from a stellar remnant 30,000 light-years away. (spaceflightnow.com)
On September 14, 2015, the Laser Interferometer Gravitational-wave Observatory (LIGO) detected gravitational waves from the merger of two black holes 29 and 36 times the mass of the Sun. Such an event is expected to be dark, but the Fermi Space Telescope detected a gamma-ray burst just a fraction of a second after LIGO's signal. (eurekalert.org)

Notable artificial sources of gamma rays include fission, such as that which occurs in nuclear reactors, and high energy physics experiments, such as neutral pion decay and nuclear fusion. (wikipedia.org)
In some fields of physics, they are distinguished by their origin: Gamma rays are created by nuclear decay while X-rays originate outside the nucleus. (wikipedia.org)
During a nuclear or radiological emergency, this test method enables a rapid measurement of the sample activity concentration of potentially contaminated samples to check against operational intervention levels (OILs) set up by decision makers that would trigger a predetermined emergency response to reduce existing radiation risks [12] . (iso.org)
We performed gamma-ray analysis to determine the amount of radioactive cesium-134 ( 134 Cs) and cesium-137 ( 137 Cs) in 259 foodstuffs five years after the Fukushima nuclear accident of 2011. (nature.com)
Although gamma-ray measurements supported that radioactivity levels in almost all foodstuffs were far below the Japanese regulatory limit, it was unknown how much of the detected radioactivity originated from the Fukushima accident as opposed to pre-Fukushima events such as the atmospheric nuclear explosions 12 that have been conducted since 1945 and the Chernobyl nuclear power plant accident of 1986. (nature.com)
Nuclear structure investigations of Sr-84 and Sr-86 using gamma-ray spectroscopic methods. (uni-koeln.de)
In contemporary nuclear physics, the European Advanced GAmma Tracking Array (AGATA) represents a crucial detection system for cutting-edge nuclear structure studies. (lu.se)
article{14b8342e-5543-40cb-baa0-be4a84ef3763, abstract = {{In contemporary nuclear physics, the European Advanced GAmma Tracking Array (AGATA) represents a crucial detection system for cutting-edge nuclear structure studies. (lu.se)
The workshop on "Hadron-Hadron and Cosmic-Ray Interactions at multi-TeV Energies" held at the ECT* centre (Trento) in Nov.-Dec. 2010 gathered together both theorists and experimentalists to discuss issues of the physics of high-energy hadronic interactions of common interest for the par- ticle, nuclear and cosmic-ray communities. (lu.se)

High Precision X-ray Measurements 2021 conference is the second edition of the HPXM2018 workshop, held at the INFN Laboratories of Frascati in 2018. (infn.it)

Using measurements of trace 134 Cs radioactivity, we investigated the contribution ratio of 137 Cs derived from the Fukushima accident on 2011 and pre-Fukushima. (nature.com)
General information on radioactivity and the measurement of radiation has been published (2). (astm.org)

Concerning the latter, particular attention is payed to advances in the capabilities of radioactive beam facilities such as the National Superconducting Cyclotron laboratory at Michigan State University, where indirect methods have been developed to better constrain thermonuclear reaction rates at X-ray burst conditions. (cern.ch)
Theoretically, during the collapse energy may be released along the axis of rotation to form a gamma-ray burst. (reasons.org)
AAVSO observers and researchers pursuing high energy sources can go beyond gamma-ray burst follow-ups to include observations of other astrophysical sources bright in gamma- and X-rays. (aavso.org)
The ability of Fermi's gamma-ray burst monitor to resolve the fine structure within these events will help us better understand how magnetars unleash their energy," said Chryssa Kouveliotou, an astrophysicist at NASA's Marshall Space Flight Center in Huntsville, Ala. The object has triggered the instrument more than 95 times since Jan. 22. (spaceflightnow.com)
The BATSE Current Gamma-Ray Burst Catalog, the BATSE GRB Team, http://gammaray.msfc.nasa.gov/batse/grb/catalog/current/ The Fourth BATSE Gamma-Ray Burst Catalog, C. A. Meegan et al. (nasa.gov)
1997). The Third BATSE BATSE Gamma-Ray Burst Catalog, C. A. Meegan et al. (nasa.gov)
The BFITS data files - containing burst and background spectral data as a function of time - and the detector response matrices (DRM) - modeling the instrument response to account for scattering and other effects - are extremely useful for gamma-ray burst analysis. (nasa.gov)
New research suggests that the two black holes might have resided inside a single, massive star whose death generated the gamma-ray burst. (eurekalert.org)
In order to power both the gravitational wave event and the gamma-ray burst, the twin black holes must have been born close together, with an initial separation of order the size of the Earth, and merged within minutes. (eurekalert.org)
By spotting the afterglow of a gamma-ray burst and measuring its redshift, then comparing it to the independent distance measurement from LIGO, astronomers can precisely constrain the cosmological parameters. (eurekalert.org)

Using this technique, we have measured the decay gamma-ray from O-15, after a O-16(gamma, n) reaction with a similar to60 MeV tagged photon. (sdu.edu.tr)
In astrophysics, gamma rays are conventionally defined as having photon energies above 100 keV and are the subject of gamma ray astronomy, while radiation below 100 keV is classified as X-rays and is the subject of X-ray astronomy. (wikipedia.org)
A gamma decay was then understood to usually emit a gamma photon. (wikipedia.org)
When a high-energy gamma-ray photon from a blazar hits a much lower-energy EBL photon, both are annihilated and produce two different particles - an electron and its antiparticle, a positron, which fly off into space and are never heard from again. (astronomy.com)
This describes the case in which a gamma photon interacts with and transfers its energy to an atomic electron, ejecting that electron from the atom. (wikidoc.org)
The kinetic energy of the resulting photoelectron is equal to the energy of the incident gamma photon minus the binding energy of the electron. (wikidoc.org)
This is an interaction in which an incident gamma photon loses enough energy to an atomic electron to cause its ejection, with the remainder of the original photon's energy being emitted as a new, lower energy gamma photon with an emission direction different from that of the incident gamma photon. (wikidoc.org)
Common methods include conventional radiography, quantitative CT (QCT), single-photon absorptiometry (SPA), dual-photon absorptiometry (DPA), quantitative ultrasonography (QUS), and dual-energy x-ray absorptiometry (DEXA). (medscape.com)
Among them, the photon absorption technique exposes the individual to radiation, the densitometry requires the individuals to be fully adapted to the liquid medium, the gamma ray spectrometry is impractical due to the high costs associated with the equipment, and the hydrometry requires an extended amount time for the determination of the body water contents. (bvsalud.org)

Students will learn in deep about the implementation of the experimental methods in the satellite (AMS-02, Fermi-LAT) and ground-based (Pierre Auger, H.E.S.S., MAGIC, VERITAS, CTA, HAWC, ARGO-YBJ) detectors of very-high energy (VHE) cosmic rays and gamma-rays, as well of the VHE neutrino detectors (IceCube, KM3NET). (ung.si)
I describe how combining results of gamma-ray absorption measurements with the Fermi-LAT with galaxy survey results can constrain these quantities. (cern.ch)

This allows one to use gamma-ray absorption to constrain the EBL, which depends strongly on a number of quantities that are interesting from an astrophysical and cosmological point of view. (cern.ch)
When a gamma ray passes through matter, the probability for absorption in a thin layer is proportional to the thickness of that layer. (wikidoc.org)
The exponential absorption holds only for a narrow beam of gamma rays. (wikidoc.org)
If a wide beam of gamma rays passes through a thick slab of concrete, the scattering from the sides reduces the absorption. (wikidoc.org)
Compton scattering is thought to be the principal absorption mechanism for gamma rays in the intermediate energy range 100 keV to 10 MeV. (wikidoc.org)
It is the tracking algorithms that deploy this information and enable insight into the sequence of interactions, providing information on the full or partial absorption of the γ ray. (lu.se)

Designed to look outward at cosmic sources of gamma rays, CGRO also caught rare but tantalizing glimpses of gamma rays coming from Earth. (sciencedaily.com)

Gamma-ray astronomy is a branch of astronomy that deals with the detection and study of gamma rays in the cosmos. (newworldencyclopedia.org)
Thus, gamma-ray astronomy provides the opportunity for scientists to study objects and phenomena in the universe that are associated with extremely high energies. (newworldencyclopedia.org)
For this reason, the development of gamma-ray astronomy was delayed until it became possible to place detectors above most (if not all) of the atmosphere, using balloons or spacecraft. (newworldencyclopedia.org)
In the late 1960s and early 1970s, gamma-ray astronomy received an unexpected boost from a constellation of defense satellites. (newworldencyclopedia.org)
The field of gamma-ray astronomy took great leaps forward with the SAS-2 (1972) and the COS-B (1975-1982) satellites. (newworldencyclopedia.org)
During its High Energy Astronomy Observatory program in 1977, NASA announced plans to build a "great observatory" for gamma-ray astronomy. (newworldencyclopedia.org)
implementation in Cherenkov ground-based gamma-ray astronomy. (ung.si)

GRBs are extremely powerful flashes of gamma rays observed from a random direction on the sky about once a day. (cerncourier.com)

Due to the uncertainty associated with the results obtained with this test method, test samples requiring more accurate test results can be measured using high-purity germanium (HPGe) detectors gamma-ray spectrometry in a testing laboratory, following appropriate preparation of the test samples [7][8] . (iso.org)
Airborne measurements for Rn-222 were the average of 25 stations determined by alpha track detectors. (cdc.gov)

These include Blazars and other Active Galactic Nuclei, and Galactic gamma-ray sources like flare stars and X-ray binaries. (aavso.org)

In a photonuclearexperiment, we have measured the decay gamma-ray in coincidence with a single knocked-out neutron for the first time. (sdu.edu.tr)
A gamma ray, also known as gamma radiation (symbol γ or γ {\displaystyle \gamma } ), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. (wikipedia.org)
Gamma rays from radioactive decay are in the energy range from a few kiloelectronvolts (keV) to approximately 8 megaelectronvolts (MeV), corresponding to the typical energy levels in nuclei with reasonably long lifetimes. (wikipedia.org)
Natural sources of gamma rays originating on Earth are mostly a result of radioactive decay and secondary radiation from atmospheric interactions with cosmic ray particles. (wikipedia.org)
The first gamma ray source to be discovered was the radioactive decay process called gamma decay. (wikipedia.org)
In this type of decay, an excited nucleus emits a gamma ray almost immediately upon formation. (wikipedia.org)
Natural sources of gamma rays on Earth include gamma decay from naturally occurring radioisotopes such as potassium-40, and also as a secondary radiation from various atmospheric interactions with cosmic ray particles. (wikipedia.org)
With SPI on INTEGRAL, the gamma-ray line from decay of radioactive 26Al could be measured at unpredecented spectroscopic precision. (cern.ch)

Work by Eugene Feenberg and H. Primakoff in 1948, Sachio Hayakawa and I.B. Hutchinson in 1952, and Morrison in 1958, led to the prediction that a number of different phenomena in the cosmos would result in the emission of gamma rays. (newworldencyclopedia.org)
Significant gamma-ray emission from our galaxy was first detected in 1967 by the gamma-ray detector aboard the OSO-3 satellite. (newworldencyclopedia.org)
Nucleosynthesis sources are probably minor contributors to Galactic positrons, as deduced from the bulge-centered spatial distribution of the annihilation gamma-ray emission. (cern.ch)
In a recent issue of the Astrophysical Journal Letters a team American and Canadian astronomers reported on the discovery of radio afterglow emission from gamma-ray burster GRB 090423 , which exploded at a redshift of 8.3.2 This object manifests the highest known redshift in the universe by a wide margin. (reasons.org)
Characterization techniques such as Thermally Stimulated Current (TSC) or Thermoelectric Emission Spectroscopy (TEES) have been used for trap identification, while time-of-flight techniques have been employed to determine carrier mobility and lifetime but it has proven difficult to correlate the results of these independent measurements. (spie.org)
The faint Cherenkov flashes are recorded with the large H.E.S.S. telescopes and thus allow studies of the original gamma-ray emission in an indirect manner. (mpg.de)
They collide with the nuclei of stable atoms, resulting in the emission of energetic protons, alpha and beta particles, and gamma radiation. (msdmanuals.com)

It is applicable to nuclides emitting gamma-rays with energies greater than 20 keV. (astm.org)

Rutherford and his co-worker Edward Andrade measured the wavelengths of gamma rays from radium, and found they were similar to X-rays, but with shorter wavelengths and thus, higher frequency. (wikipedia.org)
They confirmed the earlier findings of the gamma-ray background, produced the first detailed map of the sky at gamma-ray wavelengths, and detected a number of point sources. (newworldencyclopedia.org)
An accurate measurement of the EBL is as fundamental to cosmology as measuring the heat radiation left over from the Big Bang - the cosmic microwave background - at radio wavelengths. (astronomy.com)
In a new study, Alberto Dominguez and six co-authors - based on observations spanning wavelengths from radio waves to very energetic gamma rays obtained from several NASA spacecraft and several ground-based telescopes - describe the best measurement yet of the evolution of the EBL over the past 5 billion years. (astronomy.com)

The amount, or intensity, of gamma rays depends on the type of radioactive material at the site, its concentration and depth from the surface, and physical distribution in the soil. (cdc.gov)
First, the co-authors compared the Fermi findings to the intensity of X-rays from the same blazars measured by X-ray satellites Chandra, Swift, Rossi X-ray Timing Explorer, and XMM/Newton and lower-energy radiation measured by other spacecraft and ground-based observatories. (astronomy.com)
Precise gamma-ray intensity measurements in B-10. (uni-koeln.de)
Materials for shielding gamma rays are typically measured by the thickness required to reduce the intensity of the gamma rays by one half (the half value layer or HVL). (wikidoc.org)
For example, gamma rays that require 1 cm (0.4 inches) of lead to reduce their intensity by 50% will also have their intensity reduced in half by 6 cm (2½ inches) of concrete or 9 cm (3½ inches) of packed dirt. (wikidoc.org)
Maps of gamma-ray intensity Ng, interstellar gas density Np, and X-ray intensity Nx. (scitechdaily.com)
Astronomers knew a relation that the intensity of gamma-ray from protons is proportional to the interstellar gas density obtained by radio-line imaging observations. (scitechdaily.com)
On the other hand, gamma-rays from electrons are also expected to be proportional to X-ray intensity from electrons. (scitechdaily.com)
Therefore, they expressed the total gamma-ray intensity as the sum of two gamma-ray components, one from the proton origin and the other from the electron origin. (scitechdaily.com)

Gamma rays and X-rays are both electromagnetic radiation, and since they overlap in the electromagnetic spectrum, the terminology varies between scientific disciplines. (wikipedia.org)
In 1914, gamma rays were observed to be reflected from crystal surfaces, proving that they were electromagnetic radiation. (wikipedia.org)
Gamma rays are the most energetic form of electromagnetic radiation and are produced by phenomena such as explosions and high-speed collisions. (newworldencyclopedia.org)
Gamma rays are generally characterized as electromagnetic radiation having the highest frequency and energy, and also the shortest wavelength (below about 10 picometer ), within the electromagnetic spectrum . (wikidoc.org)

Accreting neutron stars in X-ray binaries provide a unique laboratory for thermonuclear burning at extreme temperature and density conditions. (cern.ch)
The high-energy fireworks arise from a rare type of neutron star known as a soft-gamma-ray repeater. (spaceflightnow.com)
Swift's X-Ray Telescope captured an apparent expanding halo around the flaring neutron star SGR J1550-5418. (spaceflightnow.com)
See also beta particle , gamma ray , neutron , x-ray . (cdc.gov)

Gamma-ray spectrometers with high spectral resolution are operating in space since 2002: RHESSI and SPI on INTEGRAL. (cern.ch)

Astronomers have found that the universe contains a uniform background of gamma radiation, which has been attributed to the interaction of cosmic rays with interstellar gas. (newworldencyclopedia.org)
Currently, gamma-ray bursters (see figure) rank as the brightest objects astronomers can see. (reasons.org)
During the past two years, astronomers have identified pulsing radio and X-ray signals from it. (spaceflightnow.com)
Because of the recent outbursts, astronomers will classify the object as a soft-gamma-ray repeater -- only the sixth known. (spaceflightnow.com)

The first evidence of the need for a new class of GRB came from the analysis of GRB 111209A, which erupted on 9 December 2011 and remained active for 7 hours as observed by NASA's Swift spacecraft and several other gamma-ray, X-ray and optical instruments. (cerncourier.com)

Observations of blazars by NASA's Fermi Gamma Ray Telescope spacecraft for the first time detected that gamma rays from distant blazars are indeed attenuated more than gamma rays from nearby blazars. (astronomy.com)

Both scenarios are disproved by the recent measurement of the redshift of the host galaxy by Andrew Levan of the University of Warwick and his team. (cerncourier.com)

These first gamma-ray line observations were from the spacecrafts OSO-3, OSO-7, and the Solar Maximum Mission, the last of which was launched in 1980. (newworldencyclopedia.org)
The satellite carried four major instruments which have greatly improved the spatial and temporal resolution of gamma-ray observations. (newworldencyclopedia.org)
Recent progress in gamma-ray observations has revealed that many supernova remnants emit gamma-rays at teraelectronvolts (TeV) energies. (scitechdaily.com)

Airborne contamination at these areas consists of both gamma radiation and Rn-222. (cdc.gov)
Different measurement techniques for assessing plant productivity: gas-exchange a leaf level and ecosystem level as well as hyperspectral data acquisitions (airborne and staitionary). (ufz.de)

In 1988, gamma radiation measurements showed a radiation exposure rate ranging from 17 to 2,229 x 10 -3 R/yr above a bkg average of 73x10 -3 R/yr ( Bechtel, 1989a ). (cdc.gov)
this paper is tackling the radiation measurements during Storage Ring operation at 200mA, 2.5GeV. (lu.se)
Radiation measurements results received before and after the chopper installation in the linac and additionally problems with radiation levels while the beam current is increasing to the designed 500mA value will be presented. (lu.se)

B. Fu, Gamma-ray Spectroscopy of 33 P and 33 S and Upgrade and Commissioning of the Lund-York-Cologne CAlorimeter , PhD thesis, Universität zu Köln, 2018. (lu.se)

Dual-energy x-ray absorptiometry (DEXA) detects small changes in bone mass by comparing the patient's bone density to that of healthy adults (T score) and to age-matched adults (Z score). (medscape.com)
Ultrasonic measurement of velocity through the bone has also been used to determine bone density. (medscape.com)
It is a sensitive technique and can detect changes in bone density only 6-12 months after a previous measurement is obtained. (medscape.com)
Density measurements of the spine or hip are used. (medscape.com)
Bone-density measurements can be performed by using X-ray methods, such as DEXA, QCT, and ultrasonic methods. (medscape.com)

X-rays or gamma rays are often used to quantify BMD. (medscape.com)

I n the wake of the success of the 2018 edition, HPXM2021 is planned with the twofold aim to consolidate the existing interconnections between the research teams and foster creating new ones, offering the opportunity for all the participants to discuss and share the results of their activities focusing on a common protagonist: X-ray precision detection. (infn.it)

However, the afterglow properties of GRB 090423 are not sufficiently different from other gamma-ray bursters to suggest that it arose from the explosion of a metal-free star. (reasons.org)

This major change between 20 and 50 mbsf seems to correspond to either a general change in lithology or a diagenetic overprint, which is mirrored in low NGR counts (Fig. F22 ) and high L* values (see "Natural gamma radiation" ). (iodp.org)

Rutherford also noted that gamma rays were not deflected (or at least, not easily deflected) by a magnetic field, another property making them unlike alpha and beta rays. (wikipedia.org)

The microwave technique is complimentary to contact-based methods and provides both trap identification and lifetime determination in a single measurement. (spie.org)
Simple laboratory techniques were developed to measure the physical properties needed in these prediction methods and to check these methods through a series of systematic measurements. (epa.gov)
Mobile Gamma Spectrometry: Optimisation and Development of Methods for Mapping and Locating Lost Radioactive Sources. (lu.se)

However, gamma rays are also produced by electrons, it is necessary to determine whether the proton or electron origin is dominant, and to measure the ratio of the two contributions (see also Figure 1). (scitechdaily.com)
The originality of this research is that gamma-ray radiation is represented by a linear combination of proton and electron components. (scitechdaily.com)

This test method can be used for the measurement of any potentially contaminated environmental matrices (including soil), food and feed samples as well as industrial materials or products that have been properly conditioned. (iso.org)
By preparing the entire soil core collection, sufficient homogeneous sample is available for such gamma-ray spectrometry and other radiochemical measurements. (astm.org)

Color reflectance spectrometry and split-core point-logger magnetic susceptibility measurements were obtained for every section in each hole in 2 cm steps. (iodp.org)
Physical property and paleomagnetism measurements of basement rocks will help elucidate the cause of the distinct magnetic contrasts between the East and Southwest Subbasins. (iodp.org)

In 2004, a giant flare from another soft-gamma-ray repeater was so intense it measurably affected Earth's upper atmosphere from 50,000 light-years away. (spaceflightnow.com)

However, the European INTEGRAL gamma-ray satellite did not confirm the signal. (eurekalert.org)

Although the gamma ray resolution was insufficient to perform a full analysis at that time, Professor Gavin Rowell and Dr. Sabrina Einecke of the University of Adelaide and the H.E.S.S. team dramatically improved the spatial resolution and sensitivity of gamma rays over the years, making it possible to compare them precisely with interstellar gas. (scitechdaily.com)

Our results show that it may be feasible to perform measurements of the ultrahigh-energy neutrino flux from cosmic origin during the expected lifetime of the HAWC observatory. (hindawi.com)
The HAWC observatory was designed to detect and characterize the sources of high-energy gamma-rays in the energy range between 100 GeV and 100 TeV [ 2 ] and started full operations in April 2015. (hindawi.com)

The first true astrophysical gamma-ray sources detected were solar flares, which revealed the strong 2.223 MeV line predicted by Morrison. (newworldencyclopedia.org)
Gamma-rays are another cosmic probe that provides information about the acceleration mechanisms that occur in astrophysical sources. (hindawi.com)

Gamma rays are often produced alongside other forms of radiation such as alpha or beta . (wikidoc.org)

The latest cosmic-ray results from various ground-based obser- vatories were also presented with an emphasis on the phenomenological modeling of the first hadronic interactions of the extended air-showers generated in the Earth atmosphere. (lu.se)

Gamma rays were first thought to be particles with mass, like alpha and beta rays. (wikipedia.org)
The presentation of such a wide range of topics is built up over the common main goals of an (astro) particle physicist, which are the measurement of the energy (calorimetry), the reconstruction of the trajectory, and constraining the nature of the high-energy particles. (ung.si)
Alpha particles generally carry more energy than gamma or beta particles , and deposit that energy very quickly while passing through tissue. (cdc.gov)
The candidate particles, ranging from protons to nuclei as massive as iron, generate "extensive air-showers" (EAS) in interactions with air nuclei when en- tering the Earth's atmosphere. (lu.se)

Space telescopes are useful for the study of cosmic gamma rays, most of which are absorbed by the Earth's atmosphere. (newworldencyclopedia.org)
Since the H.E.S.S. telescopes measure light generated within the atmosphere it is very helpful to also check for any other changes in the atmosphere while recording gamma rays. (mpg.de)

Physical property measurements of core samples and wireline logging measurements will provide stratigraphic information for correlation with regional seismic profiles. (iodp.org)

Anatomy2

Organisms5

Diseases3

Chemicals and Drugs7

Analytical, Diagnostic and Therapeutic Techniques and Equipment11

Phenomena and Processes22

Technology, Industry, Agriculture1

Information Science1

Health Care11

BURSTS19

Radionuclides9

Attenuation4

Spectrometry measurements1

Terrestrial gamma-r2

Photons13

Radionuclide3

Situ3

Compton Gamma Ray O3

Positron annihilation2

Space Telescope3

Nuclear9

20211

Radioactivity2

Burst10

Photon9

Fermi-LAT2

Absorption6

CGRO1

Astronomy7

Flashes of gamma rays1

Detectors2

Active Galact1

Decay8

Emission7

Emitting gamma-rays1

Wavelengths4

Intensity9

Electromagnetic radiation4

Neutron4

Spectral1

Astronomers4

NASA's Swift1

Blazars1

Redshift1

Observations3

Airborne2

Radiation measurements3

Spectroscopy1

Density5

Quantify1

Detection1

Afterglow1

Natural gamma1

Noted that gamma rays1

Methods3

Electron2

Soil2

Magnetic2

Flare1

INTEGRAL1

Improved the spatial1

Observatory2

Astrophysical2

Rays are often1

Hadronic1

Particles4

Telescopes2

Correlation1