Radiation damage and xenon release in quartz and fused silica following ion bombardment

Abstract

Single-crystalline quartz and fused silica were bombarded with 40 keV xenon ions to give integrated ion doses of up to 2 x 1016 ions/cm2. A t low dose (8 x 1O'O ions/cm') diffusional release processes dominated with activation enthalpies of 58 and 61 kcal/mol for quartz (diffusion along and perpendicular to the c-axis respectively) and 72 kcal/mol for fused silica. Diffusion in the amorphous phase was markedly slower than diffusion in the crystalline phase. A t doses 2 4 x 1013 ions/cmz radiation damage in the form of a phase change to a quasi-amorphous state occurred in quartz, as revealed by reflection electron diffraction. The annealing of this structural damage coincided with enhanced thermally activated gas release a t temperatures below those of volume diffusion. Fused silica showed a similar enhanced release a t high bombardment dose. Thus, the quasi-amorphous phase produced by ion bombardment is different from that of fused silica. The present results indicate further, in agreement with the literature on neutron irradiated quartz and fused silica, that both materials approach a common state a t a high level of radiation damage. Quarzeinkristalle und Qnarzglasproben werden mit 40 keV Xenonionen bis zu Gesamtionendosen von 2 x 1 0 ' 6 Ionen/cm2 beschosson. Bei niedriger Dosis (8 x 10'0 Ionen/cm2) liegt Gasabgabe durch Diffusionsprozesse vor, mit Aktivierungsenthalpien von 58 und 61 kcal/Mol fiir Quarz (Diffusion parallel und senkrecht zur c-Achse) und 72 kcal/Mol fur Quarzglas. Die Diffusion in der amorphen Phase verliiuft wesentlich langsamer als die Diffusion in der kristallinen Phase. Durch Elektronenbeugung in Reflexion wird gezeigt, daB bei Dosen 2 4 x 10ls Ionen/cm2 inQuarzkristallen Strahlenschiiden in Form einer Phasenumivandlung zu einer quasi-amorphen Phase auftreten. Das Ausheilen dieser struktorellenStrahlenschiiden fiillt mit thermisch aktivierter Gasabgabe zusammen und findet bei Temperaturen statt, die unterhalb derjenigen fiir Gitterdiffusion liegea. Quarzglas zeigt eine ahnlich gesteigerte Gasabgabe bei hoher BeschuSdosis. Folglich ist die quasi-amorphe Phase, die durch IonenbeschuB erzeugt wird, von der des normalen Quarzglases verschieden. I n ubereinstimmung mit der Literatur iiber neutronenbestrahlten kristallinen Quarz und Quarzglas deuten die vorliegenden Ergebnisse ferner darauf hin, daD bei einem hohen Grad von Strahlenschiiden beide Materialien einen gemeinsamen Zustand erreichen.

Radiation-enhanced diffusion of Ag produced by Ar implantation into Ag-doped glass

“…This was not attempted due to the limits on the bending powers of both the analysing and switching magnets. Similar observations were made earlier in which a second distribution is formed after Kr implantation into glass [20,21]. The latter was accounted for as arising from radiation compaction of the glass matrix.…”

Фотолюминесценция аморфного SiO-=SUB=-2-=/SUB=-, подвергнутого имплантации ионов Ar-=SUP=-+-=/SUP=-

“…Доза имплантации (D) варьировалась от 3 • 10 13 до 1 • 10 16 Ar + /cm 2 . Эта доза исключала образование кластеров внедренных частиц, которые возникают лишь при D ≈ 10 18 ion/cm 2 [11].…”

Absence of single critical dose for the amorphization of quartz under ion irradiation

“…In the present work, we perform the classical molecular dynamic (MD) simulations of complete amorphization process of α-quartz. Although, in previous experiments [23][24][25], there were a number of different ions, such as, B + , Ar + , H + , He + and Na + etc used to amorphize α-quartz by ion irradiation, we selected for concreteness the 50 keV 23 Na ions to study the amorphization process of quartz on atomistic level. The simulations were carried out by the following two steps.…”

“…SiO 2 is a material of great interest due to its wide use as an insulator in Si microelectronics [21] and as one of the base materials for present and future optoelectronics [22]. Its crystalline equilibrium state, α-quartz, can be rendered amorphous by ion irradiation [23][24][25][26][27][28]. The atom-level mechanisms behind this amorphization are not, however, well understood.…”