The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Echelle

(also echelle grating), a diffraction grating of the reflection type that concentrates the energy of diffracted radiation in spectra of fifth to 500th order (seeORDER OF INTERFERENCE). When the number of grooves is relatively small (10–100 lines per mm), echelles are characterized by a very high dispersion and a very high resolving power. As a dispersing element, the echelle has parameters that are intermediate between those of the Michelson reflection echelon and the echelette.

The profile of the grooves of an echelle is the same as that of the grooves of an echelette. The blaze angle, or the angle of inclination of the mirror surface of a groove, may be as high as 75°.

Echelles are used in high-resolution monochromators and in cross-dispersion spectrographs. For example, the STE-I spectrograph contains a prism and an echelle whose spectrum scanning planes are mutually perpendicular.

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References in periodicals archive

Avec la SCALA, la marque Skoda a gravi plusieurs echelons dans l'echelle du developpement.

Skoda Scala: Coup de jeune

The sounding rocket payload, Colorado High-resolution Echelle Stellar Spectrograph or CHESS, launched from White Sands Missile Range in New Mexico.

NASA launches CHESS to study birthplace of stars

Bakkoury, il s'agit egalement d'oeuvrer pour atteindre l'equilibre economique dans les meilleurs delais, ajoutant, a cet egard, que cela "ne peut etre possible sans la materialisation des economies d'echelle et le deploiement de nombreux projets dans ce secteur".

Le developpement du secteur solaire ne peut se concretiser sans une intervention collective des differentes parties prenantes (Bakkoury)

La fronde sociale qui a secoue le Bresil en juin avec des manifestations massives se poursuit a moindre echelle, mais avec des groupes plus radicaux essentiellement a Rio et Sao Paulo, oE les protestations debouchent immanquablement sur des violences.

Bresil : La fronde sociale faiblit mais se radicalise

The team used an instrument called the cryogenic high-resolution infra-red echelle spectrograph, or CRIRES, mounted on the European Southern Observatory's Very Large Telescope in Chile's Atacama desert.

New technique finetunes quest for life on other worlds

The 72 papers explore such areas as physical causes and excitation mechanisms of oscillations in various types of stars, new observational findings and other enigmatic phenomena, Echelle diagrams in astero-seismology, the solar dynamo and solar activity viewed from helio-seismology, and solar and stellar hydrodynamics and magneto-hydrodynamics.

Progress in solar/stellar physics with helio- and asteroseismology; proceedings

Capability to mount large, high angle Echelle type diffraction gratings is built in.

High Resolution Spectrometer Measures 0.02 Nanometer Full Width Half Maximum Spectra

Finally to bring the story right up to date, the team that developed the LHIRES III has recently unveiled a fibre-fed Echelle spectrograph designed mainly with individual amateurs or clubs with larger aperture telescopes in mind.

2 Increased Pro-Am cooperation in spectroscopy delivers results

La presentation de notre affiche: Le reseau vasculaire: un capital a preserver pour le futur nous a permis de diffuser notre projet a une plus grande echelle.

Diane Desmarais et Lyse Pelletier

Bien que la pensee historique ait ete recemment le sujet de nombreuses recherches, peu d'entre elles tentent explicitement d'en appliquer les resultats sur une large echelle en Amerique du Nord.

Benchmarks of historical thinking: first steps

Nos etudiants ont acquis une connaissance approfondie des organismes vivants, ce qui leur permet de developper des procedes pour une production a grande echelle. Voila pourquoi ils sont tres attendus sur le marche du travail.

L'UdeS presente les premiers ingenieurs biotechnologiques