Results 161 to 170 of about 13,282 (218)
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On calculating kerma, collision kerma and radiative yields
Medical Physics, 2019PurposeTo study the relationships between dose (D), kerma (K), and collision kerma () in photon beams and to investigate total radiative yields for electrons and positrons as a function of energy. To do this accurately required calculating collision kerma directly as a function of position in a phantom and making changes to the EGSnrc package ...
Dwo Rogers
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Kerma-Area Product in Diagnostic Radiology
American Journal of Roentgenology, 2014W565 is traveling through air, and it is how the intensity (strength) of the x-ray beam is characterized [6]. Air kerma can be thought of as the number of individual x-ray photons per unit area, which therefore says nothing about the extent (area) of the x-ray beam. Although xray photon energies play a role in determining air kerma, this is a secondary
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A new Diamentor for measuring kerma‐area product and air‐kerma simultaneously
Medical Physics, 1997The new M4KDK Diamentor (PTW‐Freiburg) for measuring the air‐kerma‐area product (KAP) and air kerma (AK) simultaneously was evaluated. The special design of the Diamentor chamber influences the variation of the calibration factor with respect to the field size somewhat differently to what is the case with the classic Diamentor.
H, Gfirtner, F E, Stieve, J, Wild
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THE AIR-KERMA RATE CONSTANT: APPLICATION TO AIR-KERMA MEASUREMENTS FOR HOMELAND SECURITY
Health Physics, 2008Air-kerma rate measurements from 57Co, 60Co, and 137Cs radioactive sources were performed. These measurements were motivated by the development of new sources at the National Institute of Standards and Technology (NIST) for radiological testing of equipment for homeland security applications.
L, Pibida +3 more
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The Pre-Kerma Culture and the Beginning of the Kerma Kingdom
2021Abstract The Pre-Kerma is an Upper Nubian culture that developed between 3500 and 2500 bce. It preceded the Kerma civilization and was in part contemporaneous with the A-Group from Lower Nubia. It consisted of an agro-pastoral population that maintained contacts with Lower Nubia and produced pottery somewhat similar to that of the A ...
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Metrologia, 2009
This paper reviews the current status of air-kerma cavity standards for gamma rays from 60Co, 137Cs and 192Ir sources. It describes the basic principles and the theories to determine the air-kerma rate from the ionization current of graphite-walled cavity ionization chambers. A typical design of a cavity chamber is shown and described.
L Büermann, D T Burns
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This paper reviews the current status of air-kerma cavity standards for gamma rays from 60Co, 137Cs and 192Ir sources. It describes the basic principles and the theories to determine the air-kerma rate from the ionization current of graphite-walled cavity ionization chambers. A typical design of a cavity chamber is shown and described.
L Büermann, D T Burns
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Archaeology of the Kerma Culture
2021Kerma was a Bronze Age culture (c. 2500–1500 bce) located in what is today Sudan and southern Egypt. It is one of the earliest complex societies in Africa and, at its height, rivaled Ancient Egypt. The ancient Kerma culture spans the Pre-Kerma, examining the settlements and cemeteries of this ancient culture during the Pre-Kerma (3500–2500 bce ...
Sarah Schrader, Stuart Tyson Smith
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Air kerma rate constants for radionuclides
European Journal of Nuclear Medicine, 1988Conversion to SI units requires that the exposure rate constant which was usually quoted in R.h-1.mCi-1.cm2 be replaced by the air kerma rate constant with units m2.Gy.Bq-1.s-1. The conversion factor is derived and air kerma rate constants for 30 radionuclides used in nuclear medicine and brachytherapy are listed.
Wasserman H., Groenewald W.
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KERMA ratios in pediatric CT dosimetry
Pediatric Radiology, 2012Patient organ doses may be estimated from CTDI values. More accurate estimates may be obtained by measuring KERMA (Kinetic Energy Released in Matter) in anthropomorphic phantoms and referencing these values to free-in-air X-ray intensity.To measure KERMA ratios (R(K)) in pediatric phantoms at CT.CT scans produce an air KERMA K in a phantom and an air ...
Walter, Huda +4 more
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