Biomaterial Database

Parallel recording of electron energy loss spectra. 1981

H Shuman

Two silicon photo diode array devices were tested as parallel recording detectors for electron energy loss spectrometry (EELS). The direct bombardment of a Reticon photodiode array detector with high energy electrons (80 keV) causes an irreversible increase in diode dark current. The dark current saturates the detector amplifier after a dose of 10(-6) C/diode making it unsuitable for EELS. A scintillator coupled SIT vidicon is sensitive enough to count two high energy electrons with a spatial resolution of 100 micrometers, corresponding to 5 eV energy resolution with the electron optical system described. The large pixel-to-pixel gain variation inherent in the scintillator and vidicon can be reduced by averaging the spectrum over a large area of the target perpendicular to the dispersion direction. The L-edge of calcium for a 4 X 10(-3) weight fraction concentration biological specimen is observable in a 40 s parallel recorded spectrum. The minimum detectable concentration of calcium is estimated to be ten times better for ELLS than EDS X-ray analysis.

UI	MeSH Term	Description	Entries
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002477	Cells	The fundamental, structural, and functional units or subunits of living organisms. They are composed of CYTOPLASM containing various ORGANELLES and a CELL MEMBRANE boundary.	Cell
D004735	Energy Transfer	The transfer of energy of a given form among different scales of motion. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed). It includes the transfer of kinetic energy and the transfer of chemical energy. The transfer of chemical energy from one molecule to another depends on proximity of molecules so it is often used as in techniques to measure distance such as the use of FORSTER RESONANCE ENERGY TRANSFER.	Transfer, Energy
D013057	Spectrum Analysis	The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Spectroscopy,Analysis, Spectrum,Spectrometry
D014131	Trace Elements	A group of chemical elements that are needed in minute quantities for the proper growth, development, and physiology of an organism. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Biometal,Biometals,Trace Element,Trace Mineral,Trace Minerals,Element, Trace,Elements, Trace,Mineral, Trace,Minerals, Trace