You need JavaScript to view this

Thermally stimulated depolarization currents in the natural fluorite; Correntes de despolarizacao termicamente estimuladas na fluorita natural

Abstract

The present work deals with natural calcium fluoride from Criciuma, Santa Catarina. Thermally Stimulated Depolarization Currents (TSDC) can be used to determine the properties of dipole defects present in this crystal. The TSDC spectrum of this material shows three bands in the temperature range of 80 to 450 K. The first one, at 130 K, is due the dipoles formed by a trivalent impurity and an interstitial fluorine ion in the next nearest position of an impurity ion (nn R{sub s}{sup 3+} -F{sub i}{sup -}). The second one, at 102 k, is due to the presence of small aggregates of dipoles (like a dimer). The last band, at 360 k is due to the formation of Large Clusters. The continuous distribution model gave the best fit for these bands with mean activation energies of 0.41 eV, 0.595 eV and 1.02 eV for the first, second and third band respectively. Thermal treatments can modify the number of dipoles, dimers and clusters present in the crystal. The variation in the areas under each band can be used to measure this effect. In this work we used thermal treatments between 15 minutes and 10 hours and temperatures between 200 deg C and 500  More>>
Publication Date:
Dec 31, 1986
Product Type:
Thesis/Dissertation
Report Number:
INIS-BR-3677
Reference Number:
SCA: 440102; PA: AIX-30:013650; EDB-99:037670; SN: 99002073297
Resource Relation:
Other Information: DN: 60 refs., 41 figs., 1 tab.; TH: Tese (M.Sc.); PBD: 1986
Subject:
44 INSTRUMENTATION, INCLUDING NUCLEAR AND PARTICLE DETECTORS; CALCIUM; CALCIUM FLUORIDES; CHEMICAL DOSEMETERS; DEPOLARIZATION; FLUORITE; THERMOLUMINESCENCE; THERMOLUMINESCENT DOSEMETERS
OSTI ID:
322276
Research Organizations:
Sao Paulo Univ., SP (Brazil). Inst. de Fisica
Country of Origin:
Brazil
Language:
Portuguese
Other Identifying Numbers:
Other: ON: DE99617982; TRN: BR99H0064013650
Availability:
INIS; OSTI as DE99617982
Submitting Site:
BRN
Size:
125 p.
Announcement Date:

Citation Formats

Valerio, Mario Ernesto Giroldo. Thermally stimulated depolarization currents in the natural fluorite; Correntes de despolarizacao termicamente estimuladas na fluorita natural. Brazil: N. p., 1986. Web.
Valerio, Mario Ernesto Giroldo. Thermally stimulated depolarization currents in the natural fluorite; Correntes de despolarizacao termicamente estimuladas na fluorita natural. Brazil.
Valerio, Mario Ernesto Giroldo. 1986. "Thermally stimulated depolarization currents in the natural fluorite; Correntes de despolarizacao termicamente estimuladas na fluorita natural." Brazil.
@misc{etde_322276,
title = {Thermally stimulated depolarization currents in the natural fluorite; Correntes de despolarizacao termicamente estimuladas na fluorita natural}
author = {Valerio, Mario Ernesto Giroldo}
abstractNote = {The present work deals with natural calcium fluoride from Criciuma, Santa Catarina. Thermally Stimulated Depolarization Currents (TSDC) can be used to determine the properties of dipole defects present in this crystal. The TSDC spectrum of this material shows three bands in the temperature range of 80 to 450 K. The first one, at 130 K, is due the dipoles formed by a trivalent impurity and an interstitial fluorine ion in the next nearest position of an impurity ion (nn R{sub s}{sup 3+} -F{sub i}{sup -}). The second one, at 102 k, is due to the presence of small aggregates of dipoles (like a dimer). The last band, at 360 k is due to the formation of Large Clusters. The continuous distribution model gave the best fit for these bands with mean activation energies of 0.41 eV, 0.595 eV and 1.02 eV for the first, second and third band respectively. Thermal treatments can modify the number of dipoles, dimers and clusters present in the crystal. The variation in the areas under each band can be used to measure this effect. In this work we used thermal treatments between 15 minutes and 10 hours and temperatures between 200 deg C and 500 deg C. For thermal treatments at 300 deg C, the dipoles and dimers are created and the clusters are destroyed as the time of thermal treatment increases. At 400 deg C the clusters are created and the dipoles and dimers and 350 deg C for the clusters. (author) 60 refs., 41 figs., 1 tab.}
place = {Brazil}
year = {1986}
month = {Dec}
}