نتایج جستجو برای: alpha particle spectrometer

تعداد نتایج: 394145  

Journal: :Journal of Radioanalytical and Nuclear Chemistry 2021

Abstract The JRC applied six measurement techniques to standardise the activity of an 241 Am solution in frame 2003 key comparison CCRI(II)-K2.Am-241. methods used were alpha-particle counting at a defined small solid angle, high-efficiency particle and photon with windowless 4π CsI(Tl) sandwich spectrometer, alpha pressurised proportional counter, alpha-gamma coincidence sum counter NaI(Tl) we...

2006
JOHN M. KELLER

The radiation detection systems employed in radioanalytical chemistry laboratories have changed considerably over the past sixty years, with significant improvement realized since the early 1980s. Advancements in the areas of material science, electronics, and computer technology have contributed to the development of more sensitive, reliable, and user-friendly laboratory instruments. The four ...

2016
Michael Lawler James Smith Paul Winkler

The chemical composition of >8 nm diameter aerosol was measured using the Timeof-Flight Thermal Desorption Chemical Ionization Mass Spectrometer (TOF-TDCIMS) during CLOUD7 particle nucleation experiments in Fall 2012 at the CLOUD chamber at CERN in Geneva, Switzerland. Sulfate dominated the negative ion particle spectra during all events with enough particle mass to observe, both in experiments...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2011
Harry Y McSween Ralph L McNutt Thomas H Prettyman

Measurements by instruments on spacecraft have significantly advanced cosmochemistry. Spacecraft missions impose serious limitations on instrument volume, mass, and power, so adaptation of laboratory instruments drives technology. We describe three examples of flight instruments that collected cosmochemical data. Element analyses by Alpha Particle X-ray Spectrometers on the Mars Exploration Rov...

Journal: :Science 2004
H Y McSween R E Arvidson J F Bell D Blaney N A Cabrol P R Christensen B C Clark J A Crisp L S Crumpler D J Des Marais J D Farmer R Gellert A Ghosh S Gorevan T Graff J Grant L A Haskin K E Herkenhoff J R Johnson B L Jolliff G Klingelhoefer A T Knudson S McLennan K A Milam J E Moersch R V Morris R Rieder S W Ruff P A De Souza S W Squyres H Wänke A Wang M B Wyatt A Yen J Zipfel

The Spirit landing site in Gusev Crater on Mars contains dark, fine-grained, vesicular rocks interpreted as lavas. Pancam and Mini-Thermal Emission Spectrometer (Mini-TES) spectra suggest that all of these rocks are similar but have variable coatings and dust mantles. Magnified images of brushed and abraded rock surfaces show alteration rinds and veins. Rock interiors contain </=25% megacrysts....

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