Difference between revisions 2373330 and 2373423 on enwikiversity

[[Image:Detectors summary 3.png|thumb|right|250px|This tree diagram shows the relationship between types and classification of most common particle detectors. Credit: [[commons:User:Wdcf|Wdcf]].]]
'''Radiation detectors''' provide a signal that is converted to an electric current. The device is designed so that the current provided is proportional to the characteristics of the incident radiation.

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Coloradoite, a member of the coordination subclass of tellurides, is a covalent compound that is isostructural with sphalerite (ZnS).<ref name=Povarennykh>Povarennykh, A. S (1972). ''Crystal Chemical classification of minerals''. Vol I, pp. 120–121</ref>
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The chemical formula for coloradoite is HgTe. Theoretically the composition (%) of HgTe is Hg 61.14, Te 38.86;<ref name=Vlasov740-741>Vlasov, K. A. (1966) ''Geochemistry and Mineralogy of rare Elements and Genetic Types of Their Deposits''. Volume II ''Mineralogy of Rare Elements''. Israel Program for Scientific Translation. pp. 740–741</ref> Table 1 shows results from a chemical analyses reported by Vlasov on samples collected from two different locations. Because it is found with other telluride ores, it carries some other metals like gold and silver.<ref>Wallace, J. P. (1908) ''A study of Ore Deposits for the Practical Miner with descriptions of Ore Minerals''.</ref> In its pure form, it has the composition mentioned above. A little hard to identify, petzite which is hazardous could be mistaken for coloradoite, on the other hand, petzite is anisotropic as opposed to coloradoite being an isotropic mineral.<ref name="Ramdohr, P 1980 pg 524"/> It is a binary compound with the general formula AX.

{| class="wikitable"
|-
!colspan="6"| '''Results of chemical analyses of coloradoite (%)'''<ref name=Vlasov740-741/>
|-
| colspan="1"|Components
|colspan="2"| Kalgoorlie, Western Australia
| Lakeshore, Ontario
|-
| Hg
| 60.95
| 61.62
| 58.55
|-
| Pb
| -
| -
| 1.60
|-
| Te
| 39.98
| 38.43
| 39.10
|-
| Insoluble residue
| -
| -
| 0.25
|-
| Total
| 100.33
| 100.05
| 99.50
|}

Coloradoite has a sphalerite structure also known as the "diamond" or "blende" structure; a face centered cubic array in which Hg<sup>2+</sup> are in tetrahedral coordination with Te<sup>2−</sup>, with a stacking sequence of ABCABC.<ref name=Klein>Klein, C., Dutrow, B. (2007) The 23rd Edition of the ''Manual of Mineral Science'' (After JD Dana). Wiley, Hoboken</ref> The tetrahedra in the sphalerite group are joined together through their apices and rotated through 60° with respect to each other.<ref>Stanton, R. L. (1972), ''Ore petrology'': New York, McGraw-Hill</ref> Figure 1 shows the atomic structure of coloradoite. The structure is a unit cube with the Te<sup>2−</sup> ions at the corners and face centers. The four mercury atoms are coordinated so that each mercury atom lies at the center of a regular tetrahedron of tellurium atoms and each tellurium lies at the center of a regular tetrahedron of mercury atoms. Its crystal point group of {{overline|4}}3m and space group is F{{overline|4}}3m.<ref name="John W. Anthony Pg 105"/> It is a covalent compound with a high proportion of metallic bonding, due to its low valencies and even lower interatomic distances . It is also isotropic, meaning it has just one refractive index.<ref name=Povarennykh/>
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==Gadolinium oxysulfides==

Gadolinium oxysulfide ({{chem|Gd|2|O|2|S}}: Pr, Ce, F powder complex) based ceramics exhibit final densities of 99.7% to 99.99% of the theoretical density (7.32&nbsp;g/cm<sup>3</sup>) and an average grain size ranging from 5 micrometers to 50 micrometers in dependence with the fabrication procedure.<ref>Rossner, W., M. Ostertag, and F. Jermann. "Properties and Applications of Gadolinium Oxysulfide Based Ceramic Scintillators." Electroch(contracted; show full)<!-- footer templates -->
{{tlx|Radiation astronomy resources}}{{Principles of radiation astronomy}}{{Sisterlinks|Radiation detectors}}

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