Nanocrystal Growth in Crystalline Insulators Irradiated with High-Current Cu IONs

1998 ◽  
Vol 540 ◽  
Author(s):  
N. Kishimoto ◽  
N. Umeda ◽  
Y. Takeda ◽  
C.G. Lee ◽  
V.T. Gritsyna
Keyword(s):  
Optical Property ◽  
Spinel Oxide ◽  
Nanoparticle Growth ◽  
Metal Nanocrystals ◽  
Dose Rates ◽  
Nanocrystal Growth ◽  
Nanoparticle Morphology ◽  
Radiation Induced ◽  
Cu Ions ◽  
O 10

AbstractNegative Cu ions of 60 keV have been applied to generate metal nanocrystals embedded in insulators. Crystalline (c-), amorphous (a-)SiO2 and a spinel oxide, MgO·2(Al2O3), were irradiated at various dose rates up to about 100 µA/cm2, at a total dose of 3.O×1016 ions/cm2. In a-Sio2, morphology of nanoparticles and the resultant optical property changed with dose rate and, at a critical condition, showed in-plane arrangement of nanocrystals. The optical property of c-Si0 2 (a-quartz) was qualitatively similar to that of a-SiO2, but the implanted region of c-SiO2 showed different irradiation responses. The c-SiO2 was susceptible to radiation-induced amorphization but the nanoparticle morphology was still different from a-SiO2, suggesting a stronger depth-oriented driving force. Unlike SiO2, the spinel oxide showed good structural stability against the implantation and no tendency of the long-range atomic rearrangement. The results indicate that the crystallinity and the relevant interactions may play an important role in the nanoparticle growth during the implantation.

Nanocrystal Growth at High Dose Rates in Negative Copper-Ion Implantation Into Insulators

1997 ◽  
Vol 504 ◽  
Author(s):  
N. Kishimoto ◽  
V. T. Gritsyna ◽  
Y. Takeda ◽  
C. G. Lee ◽  
N. Umeda ◽  
...  
Keyword(s):  
Optical Properties ◽  
Ion Implantation ◽  
Dose Rate ◽  
Copper Ion ◽  
Negative Ions ◽  
Negative Ion ◽  
High Dose ◽  
Dose Rates ◽  
Nanocrystal Growth ◽  
Cu Ions

ABSTRACTNanoparticles of Cu were fabricated by negative-ion implantation, leading to spontaneous formation at high beam fluxes. Negative ions, alleviating surface charging, exhibit significant merits in carrying out low-energy implantation at high dose rates. The kinetic processes were studied by measuring dose-rate dependence of colloid formation and resultant optical properties. Negative-Cu ions of 60 keV were implanted into silica glasses at high-current densities, up to 260 μA/cm2, fixing the total dose at 3.0 × 1016 ions/cm2. Spherical nanocrystals of Cu atoms formed within a narrow region, near the projectile range of Cu ions. Simultaneously, much smaller particles spread out beyond a depleted zone, deeper than the projectile range. The nanocrystal growth and optical properties were greatly dependent on the dose rate and the specimen boundary condition. The growth process is explained by a droplet-model based on surface tension and radiation-induced diffusion. Beam-surface interactions also play an important role in the mass transport from the beam flux to the interior solid.

scholarly journals EANM position paper on the role of radiobiology in nuclear medicine

2021 ◽  
Author(s):  
An Aerts ◽  
Uta Eberlein ◽  
Sören Holm ◽  
Roland Hustinx ◽  
Mark Konijnenberg ◽  
...  
Keyword(s):  
Nuclear Medicine ◽  
Absorbed Dose ◽  
Added Value ◽  
External Irradiation ◽  
Executive Summary ◽  
Dose Rates ◽  
Biological Responses ◽  
Medical Physicists ◽  
Radiation Induced

Executive SummaryWith an increasing variety of radiopharmaceuticals for diagnostic or therapeutic nuclear medicine as valuable diagnostic or treatment option, radiobiology plays an important role in supporting optimizations. This comprises particularly safety and efficacy of radionuclide therapies, specifically tailored to each patient. As absorbed dose rates and absorbed dose distributions in space and time are very different between external irradiation and systemic radionuclide exposure, distinct radiation-induced biological responses are expected in nuclear medicine, which need to be explored. This calls for a dedicated nuclear medicine radiobiology. Radiobiology findings and absorbed dose measurements will enable an improved estimation and prediction of efficacy and adverse effects. Moreover, a better understanding on the fundamental biological mechanisms underlying tumor and normal tissue responses will help to identify predictive and prognostic biomarkers as well as biomarkers for treatment follow-up. In addition, radiobiology can form the basis for the development of radiosensitizing strategies and radioprotectant agents. Thus, EANM believes that, beyond in vitro and preclinical evaluations, radiobiology will bring important added value to clinical studies and to clinical teams. Therefore, EANM strongly supports active collaboration between radiochemists, radiopharmacists, radiobiologists, medical physicists, and physicians to foster research toward precision nuclear medicine.

Radiation‐Induced Conductivity in Plastic Films at High Dose Rates

1965 ◽  
Vol 36 (8) ◽  
pp. 2434-2443 ◽  
Author(s):  
D. M. J. Compton ◽  
G. T. Cheney ◽  
R. A. Poll
Keyword(s):  
High Dose ◽  
Plastic Films ◽  
Dose Rates ◽  
Radiation Induced

Radiation-induced color centers in LiF for dosimetry at high absorbed dose rates

1980 ◽  
Vol 175 (1) ◽  
pp. 17-18 ◽  
Author(s):  
William L. McLaughlin ◽  
Arne Miller ◽  
Stuart C. Ellis ◽  
Arthur C. Lucas ◽  
Barbara M. Kapsar
Keyword(s):  
Absorbed Dose ◽  
Color Centers ◽  
Dose Rates ◽  
Radiation Induced ◽  
Absorbed Dose Rates

Effect of Cascade Remnants on Freely Migrating Defects in Cu -1 % Au Alloys

1995 ◽  
Vol 396 ◽  
Author(s):  
A. Iwase ◽  
L. E. Rehn ◽  
P. M. Baldo ◽  
L. Funk
Keyword(s):  
Heavy Ions ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Heavy Ion ◽  
The Other ◽  
Inert Gas ◽  
Heavy Ion Irradiation ◽  
Simultaneous Irradiation ◽  
Radiation Induced ◽  
Cu Ions

AbstractThe effects of cascade remnants on Freely Migrating Defects (FMD) were studied by measuring Radiation-Induced Segregation (RIS) in Cu-l%Au at 400°C during simultaneous irradiation with 1.5-MeV He and (400-800)-keV heavy ions (Ne, Ar or Cu). The large RIS observed during 1.5-MeV He-only irradiation was dramatically suppressed under simultaneous heavy ion irradiation. For Cu simultaneous irradiation, the suppression disappeared immediately after the Cu irradiation ceased, while for simultaneous inert gas (Ne or Ar) irradiation, the suppression persisted after the ion beam was turned off. These results demonstrate that the displacement cascades created by heavy ions introduce additional annihilation sites, which reduce the steady-state FMD concentrations. As the cascade remnants produced by Cu ions are thermally unstable at 400°C, the RIS suppression occurs only during simultaneous irradiation. On the other hand, the inert gas atoms which accumulate in the specimen apparently stabilize the cascade remnants, allowing the suppression to persist.

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