Preparation of Nuclear Accelerator Targets by Focused Ion Beam Sputter Deposition

Folger, H.; Klemm, J.; Müller, M.

doi:10.1109/tns.1983.4332586

Cited by 12 publications

(3 citation statements)

References 6 publications

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“…The deposition of Mo at 1.63 × 10 −2 mbar Ar sputtering gas pressure, keeping the substrate-holder heated at 500 • C in a multilayer deposition mode (more details are presented in a previous work by the authors [3]), gave the best over 100-µm-thick Mo films in terms of adhesion, density (more than 95% of the bulk material), and being stress-free. It should be said that, in the past, a much lower Mo thickness of about 0.1 mg/cm 2 (~0.1 µm calculated for bulk density Mo), obtained using FIB [24] and ultrahigh vacuum sputtering [23], was reported. Our film thickness is comparable to the 130-µm Mo deposited by thermal spray deposition reported by Jalilian et al [22].…”

Section: Sputtering Parameters Optimizationmentioning

confidence: 95%

“…Here, we have associated with the group of physical methods different Physical Vapor Deposition (PVD) methods, such as Focused Ion Beam (FIB) or magnetron sputtering, thermal spray deposition, and plasma spray deposition. Table 1 presents a summary of the most commonly used methods for cyclotron solid target preparation and some examples of their [3,[19][20][21][22][23][24] In order to maximize the nuclear reaction yield, production should be performed at maximum proton currents. This means that the target system should provide high efficiency of heat dissipation.…”

Section: Introductionmentioning

confidence: 99%

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Medical Cyclotron Solid Target Preparation by Ultrathick Film Magnetron Sputtering Deposition

et al. 2019

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Magnetron sputtering is proposed here as an innovative method for the deposition of a material layer onto an appropriate backing plate for cyclotron solid targets aimed at medical radioisotopes production. In this study, a method to deposit thick, high-density, high-thickness-uniformity, and stress-free films of high adherence to the backing was developed by optimizing the fundamental deposition parameters: sputtering gas pressure, substrate temperature, and using a multilayer deposition mode, as well. This method was proposed to realize Mo-100 and Y-nat solid targets for biomedical cyclotron production of Tc-99m and Zr-89 radionuclides, respectively. The combination of all three optimized sputtering parameters (i.e., 1.63 × 10−2 mbar Ar pressure, 500 °C substrate temperature, and the multilayer mode) allowed us to achieve deposition thickness as high as 100 µm for Mo targets. The 50/70-µm-thick Y targets were instead realized by optimizing the sputtering pressure only (1.36 × 10−2 mbar Ar pressure), without making use of additional substrate heating. These optimized deposition parameters allowed for the production of targets by using different backing materials (e.g., Mo onto copper, sapphire, and synthetic diamond; and Y onto a niobium backing). All target types tested were able to sustain a power density as high as 1 kW/cm2 provided by the proton beam of medical cyclotrons (15.6 MeV for Mo targets and 12.7 MeV for Y targets at up to a 70-µA proton beam current). Both short- and long-time irradiation tests, closer to the real production, have been realized.

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Section: Sputtering Parameters Optimizationmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Medical Cyclotron Solid Target Preparation by Ultrathick Film Magnetron Sputtering Deposition

et al. 2019

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“…The PVD methods for direct Mo deposition described in the literature include thermal spray [26], cathodic arc [4], argon [27] and xenon [28] focused ion beam (FIB) sputtering, but no information about cyclotron beam tests of such targets is available. Even if only less than 1-µm-thick Mo coatings by FIB sputtering have been reported, the method still seems interesting because it allows extremely low target material amounts, low losses of expensive isotope-enriched material during deposition, and high purity target material.…”

Section: State-of-the-art: Cyclotron Target For 99mtc Productionmentioning

confidence: 99%

Innovative Target for Production of Technetium-99m by Biomedical Cyclotron

et al. 2018

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Technetium-99m (99mTc) is the most used radionuclide worldwide in nuclear medicine for diagnostic imaging procedures. 99mTc is typically extracted from portable generators containing 99Mo, which is produced normally in nuclear reactors as a fission product of highly enriched Uranium material. Due to unexpected outages or planned and unplanned reactor shutdown, significant 99mTc shortages appeared as a problem since 2008 The alternative cyclotron-based approach through the 100Mo(p,2n)99mTc reaction is considered one of the most promising routes for direct 99mTc production in order to mitigate potential 99Mo shortages. The design and manufacturing of appropriate cyclotron targets for the production of significant amounts of a radiopharmaceutical for medical use is a technological challenge. In this work, a novel solid target preparation method was developed, including sputter deposition of a dense, adherent, and non-oxidized Mo target material onto a complex backing plate. The latter included either chemically resistant sapphire or synthetic diamond brazed in vacuum conditions to copper. The target thermo-mechanical stability tests were performed under 15.6 MeV proton energy and different beam intensities, up to the maximum provided by the available GE Healthcare (Chicago, IL, USA) PET trace medical cyclotron. The targets resisted proton beam currents up to 60 µA (corresponding to a heat power density of about 1 kW/cm2) without damage or Mo deposited layer delamination. The chemical stability of the proposed backing materials was proven by gamma-spectroscopy analysis of the solution obtained after the standard dissolution procedure of irradiated targets in H2O2.

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