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The Reactions of Hot Fluorine-18 with Gaseous Carbon Tetrafluoride; Reactions des Atomes {sup 18}F Chauds avec le Tetrafluorure de Carbone en Phase Gazeuse; Reaktsii goryachikh atomov ftora-18 s gazovoj fazoj tetraftormetana; Reacciones de Atomos Calientes de Fluor-18 con Tetrafluoruro de Carbono Gaseoso

Conference:

Abstract

Studies on the reactions of hot Fie atoms with carbon tetrafluoride are reported. Gaseous samples were exposed to the 40-60 MeV (maximum) bremsstrahlung beam of the Yale University Electron Accelerator. The F{sup 19} ({gamma}, n) F{sup 18} process produces F{sup 18} with a kinetic energy of the order of 10{sup 5}-10{sup 6} eV. These species lose energy by collision and are expected to reach the ''chemical'' energy range (< 100 eV) as ground state atoms. Ethylene was found to be a good scavenger for thermal F{sup 18} atoms. Analysis of products was made using standard radio-gas chromatography techniques. The system was found to be quite sensitive to extraneous radiation damage effects and appropriate precautions were taken. Hot displacement reactions, similar to those observed for hot hydrogen, but much less efficient, were found: F{sup 18} + CF{sup 4} --> CF{sub 3}F{sup 18} + F, F{sup 18} +CF{sub 4} --> CF{sub 2}F{sup 18} + (F + F), It was impossible to study the abstraction reaction F{sup 18} + CF{sub 4} --> CF{sub 3} + FF{sup 18} directly. However, indirect evidence suggests that it also has a low efficiency. Detailed studies of the effect of moderator on the F{sup 18} + CF{sub 4}  More>>
Authors:
Colebourne, N.; Todd, J. F.J.; Wolfgang, R. [1] 
  1. Yale University, New Haven, CT (United States)
Publication Date:
Apr 15, 1965
Product Type:
Conference
Report Number:
IAEA-SM-57/72
Resource Relation:
Conference: Symposium on Chemical Effects Associated with Nuclear Reactions and Radioactive Transformations, Vienna (Austria), 7-11 Dec 1964; Other Information: 30 refs., 9 figs., 8 tabs.; Related Information: In: Chemical Effects of Nuclear Transformations Vol. I. Proceedings of the Symposium on Chemical Effects Associated with Nuclear Reactions and Radioactive Transformations| 457 p.
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ACCELERATORS; BREMSSTRAHLUNG; CARBON TETRAFLUORIDE; ELECTRON BEAMS; ETHYLENE; EV RANGE 10-100; FLUORINE 18; FLUORINE 19 TARGET; GAS CHROMATOGRAPHY; HYDROGEN; METHANE; MEV RANGE 10-100; MODERATORS; PHOTONUCLEAR REACTIONS; RADIATION EFFECTS
OSTI ID:
22141766
Research Organizations:
International Atomic Energy Agency, Vienna (Austria); Joint Commission on Applied Radioactivity of the International Council of Scientific Unions, Paris (France)
Country of Origin:
IAEA
Language:
English
Contract Number:
Contract SAR/AT(30-1)-1957
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13M3296096367
Submitting Site:
INIS
Size:
page(s) 149-175
Announcement Date:
Oct 24, 2013

Conference:

Citation Formats

Colebourne, N., Todd, J. F.J., and Wolfgang, R. The Reactions of Hot Fluorine-18 with Gaseous Carbon Tetrafluoride; Reactions des Atomes {sup 18}F Chauds avec le Tetrafluorure de Carbone en Phase Gazeuse; Reaktsii goryachikh atomov ftora-18 s gazovoj fazoj tetraftormetana; Reacciones de Atomos Calientes de Fluor-18 con Tetrafluoruro de Carbono Gaseoso. IAEA: N. p., 1965. Web.
Colebourne, N., Todd, J. F.J., & Wolfgang, R. The Reactions of Hot Fluorine-18 with Gaseous Carbon Tetrafluoride; Reactions des Atomes {sup 18}F Chauds avec le Tetrafluorure de Carbone en Phase Gazeuse; Reaktsii goryachikh atomov ftora-18 s gazovoj fazoj tetraftormetana; Reacciones de Atomos Calientes de Fluor-18 con Tetrafluoruro de Carbono Gaseoso. IAEA.
Colebourne, N., Todd, J. F.J., and Wolfgang, R. 1965. "The Reactions of Hot Fluorine-18 with Gaseous Carbon Tetrafluoride; Reactions des Atomes {sup 18}F Chauds avec le Tetrafluorure de Carbone en Phase Gazeuse; Reaktsii goryachikh atomov ftora-18 s gazovoj fazoj tetraftormetana; Reacciones de Atomos Calientes de Fluor-18 con Tetrafluoruro de Carbono Gaseoso." IAEA.
@misc{etde_22141766,
title = {The Reactions of Hot Fluorine-18 with Gaseous Carbon Tetrafluoride; Reactions des Atomes {sup 18}F Chauds avec le Tetrafluorure de Carbone en Phase Gazeuse; Reaktsii goryachikh atomov ftora-18 s gazovoj fazoj tetraftormetana; Reacciones de Atomos Calientes de Fluor-18 con Tetrafluoruro de Carbono Gaseoso}
author = {Colebourne, N., Todd, J. F.J., and Wolfgang, R.}
abstractNote = {Studies on the reactions of hot Fie atoms with carbon tetrafluoride are reported. Gaseous samples were exposed to the 40-60 MeV (maximum) bremsstrahlung beam of the Yale University Electron Accelerator. The F{sup 19} ({gamma}, n) F{sup 18} process produces F{sup 18} with a kinetic energy of the order of 10{sup 5}-10{sup 6} eV. These species lose energy by collision and are expected to reach the ''chemical'' energy range (< 100 eV) as ground state atoms. Ethylene was found to be a good scavenger for thermal F{sup 18} atoms. Analysis of products was made using standard radio-gas chromatography techniques. The system was found to be quite sensitive to extraneous radiation damage effects and appropriate precautions were taken. Hot displacement reactions, similar to those observed for hot hydrogen, but much less efficient, were found: F{sup 18} + CF{sup 4} --> CF{sub 3}F{sup 18} + F, F{sup 18} +CF{sub 4} --> CF{sub 2}F{sup 18} + (F + F), It was impossible to study the abstraction reaction F{sup 18} + CF{sub 4} --> CF{sub 3} + FF{sup 18} directly. However, indirect evidence suggests that it also has a low efficiency. Detailed studies of the effect of moderator on the F{sup 18} + CF{sub 4} system have been made. The data obtained were analysed by means of the kinetic theory of hot reactions. The system was found to be in accord with this formalism, providing quantitative confirmation of the present interpretation of the results. The carbon tetrafluoride and methane systems provide a basis for some tentative conclusions on the mechanisms of hot fluorine atom reactions. At present it appears that with certain important, but natural, modifications the model first developed for hot hydrogen atoms is applicable [French] Le memoire est consacre a des etudes sur les reactions des atomes {sup 18}F chauds avec le tetrafluorure de carbone. Des echantillons gazeux ont ete exposes a un faisceau de rayonnements de freinage de 40 a 60 MeV (maximum) emis par l'accelerateur d'electrons de l'Universite Yale. Le processus {sup 19}F ({gamma}, n){sup 18}F donne des atomes de {sup 18}F d'une energie cinetique de l'ordre de 10{sup 5} a 10{sup 6} eV. Ces especes perdent de l'energie par choc et doivent atteindre la gamme des energies 'chimiques' (< 100 eV) en tant qu'atomes a l'etat fondamental. Les auteurs ont constate que Vethylene etait un excellent agent de balayage pour les atomes {sup 18}F thermiques. Ils ont analyse les produits a l'aide de methodes courantes de radiochromatographie en phase gazeuse. Le systeme s'est revele tres sensible aux effets de rayonnements etrangers; aussi les mesures de precaution appropriees ont-elles ete prises. Des reactions de deplacement, analbgues a celles qui ont ete observees pour l'hydrogene chaud mais beaucoup moins efficaces, ont ete relevees; ce sont les reactions suivantes: {sup 18}F + {sup 4}CF --> CF{sub 3}{sup 18}F + F, {sup 18}F + CF{sub 4} --> CF{sub 2}{sup 18}F + (F + F), Il n'a pas ete possible d'etudier directement la reaction d'enlevement {sup 18}F + CF{sub 4} --> CF{sub 3} + F{sup 18}F. Cependant, certains indices donnent a penser que cette reaction a egalement une faible efficacite. Les auteurs ont etudie en detail l'effet de ralentissement sur le systeme {sup 18}F + CF{sub 4}. Ils ont analyse les donnees obtenues en se fondant sur la theorie cinetique des reactions chaudes. Ils ont constate que le systeme etait conforme a cette theorie, ce qui a fourni une confirmation quantitative de l'interpretation actuelle des resultats. Les systemes methane et tetrafluorure de carbone fournissent une base a certaines conclusions provisoires sur les mecanismes des reactions des atomes de fluor chauds. Il semble a present que, moyennant certaines modifications importantes mais naturelles, le modele qui avait tout d'abord ete mis au point pour les atomes d'hydrogene chauds soit applicable aux atomes de fluor chauds. (author) [Spanish] La memoria describe estudios de las reacciones de atomos calientes de {sup 18}F con tetrafluoruro de carbono. Se expusieron muestras gaseosas al haz de 40 a 60 MeV (maximo) de radiaciones de frenado del acelerador de electrones de la Universidad de Yale. En virtud de la reaccion {sup 19}F ({gamma}, n) {sup 18}F se produce {sup 18}F con una energia cinetica del orden de 10{sup 5} a 10{sup 6} eV. Estas especies pierden energia por choque y se espera que alcancen el intervalo de energias 'quimicas' (< 100 eV) como atomos en el estado fundamental. Se comprobo que el etileno constituye un buen depurador para los atomos de {sup 18}F termicos. El analisis de los productos se efectuo por tecnicas corrientes de radiocromatografia en fase gaseosa. Se encontro que el sistema es bastante sensible a los danos producidos por radiaciones externas, por lo que se adoptaron precauciones para evitar la penetracion de estas. Se observaron reacciones de desplazamiento calientes analogas a las que se producen con hidrogeno caliente, pero de rendimiento mucho menos elevado, {sup 18}F + {sup 4}CF --> CF{sub 3}{sup 18}F + F, {sup 18}F + CF{sub 4} --> CF{sub 2}{sup 18}F + (F + F), No fue posible estudiar directamente la reaccion de abstraccion {sup 18}F + CF{sub 4} --> CF{sub 3} + F{sup 18}F. pero pruebas indirectas sugieren que su rendimiento es tambien reducido. Se ha estudiado detalladamente el efecto de un moderador sobre el sistema {sup 18}F + CF{sub 4}. Los datos experimentales se analizaron con ayuda de la teoria cinetica de las reacciones calientes. Se encontro que el sistema se ajusta a este formalismo, lo cual confirma cuantitativamente la interpretacion actual de los resultados. Los sistemas tetrafluoruro de carbono y metano han servido de.base para formular algunas hipotesis sobre los mecanismos de reaccion de los atomos calientes de fluor. A juicio de los autores, el modelo establecido para los atomos calientes de hidrogeno puede, con ciertas modificaciones logicas, aplicarse a dichos sistemas. (author) [Russian] Soobshhaetsja o reakcijah gorjachih atomov F{sup 18} s tetraftorometanom. Gazoobraznye obrazcy obluchalis' tormoznym izlucheniem s jenergiej 40 - 60 Mjev (maksimum) na jelektronnom uskoritele Jel'skogo universiteta. Process F{sup 19} ({gamma}, n) F{sup 18} flaeT F{sup 18} s kineticheskoj jenergiej porjadka 10{sup 5} - 10{sup 6} jev. Jeti obrazcy terjajut jenergiju v rezul'tate stolknovenij i, kak predpolagaetsja, dostignut velichiny ''himicheskoj'' energii (<100 jev) kak osnovnogo sostojanija atomov. Bylo najdeno, chto jetilen javljaetsja horoshim akceptorom teplovyh atomov F{sup 18}. Byl sdelan analiz produktov pri ispol'zovanii standartnyh metodov radio-gazohromato- grafii. Sistema, kak bylo najdeno, javljaetsja vpolne chuvstvitel'noj k vneshnim jeffektam radiacionnogo povrezhdenija, i pojetomu bylo prinjaty sootvetstvujushhie mery predostorozhnosti . Byli najdeny sledujushhie reakcii gorjachego zameshhenija, podobnye reakcijam, nabljudaemym dlja gorjachego vodoroda, no gorazdo menee jeffektivnye: F{sup 18} + CF{sup 4} --> CF{sub 3}F{sup 18} + F, F{sup 18} +CF{sub 4} --> CF{sub 2}F{sup 18} + (F + F), kazalos' nevozmozhnym izuchit' reakciju otdelenija prjamo: F{sup 18} + CF{sub 4} --> CF{sub 3} + FF{sup 18} Odnako kosvennye dokazatel'stva govorjat o tom, chto ona takzhe imeet nizkuju jeffektivnost. Podrobno izuchalis' jeffekty zamedlitelja na sistemu F{sup 10} + CF{sub 4}. Poluchennye dannye analizirovalis' s pomoshh'ju kineticheskoj teorii gorjachih reakcij. Bylo najdeno, chto jeta sistema soglasuetsja s dannym ob{sup j}asneniem pri uslovii kolichestvennogo podtverzhdenija takogo tolkovanija rezul'tatov. Sistemy tetraftormetana i metana obespechivajut osnbvu dlja nekotoryh predvaritel'nyh vyvodov otnositel'no mehanizma reakcij gorjachih atomov ftora. V nastojashhee vremja predstavljaetsja, chto s nekotorymi vazhnymi, no estestvennymi izmenenijami, model', vpervye razrabotannaja dlja gorjachih atomov vodoroda, primenima i zdes. (author)}
place = {IAEA}
year = {1965}
month = {Apr}
}