Authors:Gerrie Lange First page: 24 Abstract: This paper presents a design and working principle for a combined powder-in-gas target. The excellent surface-to-volume ratio of micrometer-sized powder particles injected into a forced carrier-gas-driven environment provides optimal beam power-induced heat relief. Finely dispersed powders can be controlled by a combined pump-driven inward-spiraling gas flow and a fan structure in the center. Known proton-induced nuclear reactions on isotopically enriched materials such as 68Zn and 100Mo were taken into account to be conceptually remodeled as a powder-in-gas target assembly, which was compared to thick target designs. The small irradiation chambers that were modeled in our studies for powdery ‘thick’ targets with a mass thickness (g/cm2) comparable to 68Zn and 100Mo resulted in the need to load 2.5 and 12.6 grams of the isotopically enriched target material, respectively, into a convective 7-bar pressured helium cooling circuit for irradiation, with ion currents and entrance energies of 0.8 (13 MeV) and 2 mA (20 MeV), respectively. Current densities of ~2 μA/mm2 (20 MeV), induces power loads of up to 4 kW/cm2. Moreover, the design work showed that this powder-in-gas target concept could potentially be applied to other radionuclide production routes that involve powdery starting materials. Although the modeling work showed good convective heat relief expectations for micrometer-sized powder, more detailed mathematical investigation on the powder-in-gas target restrictions, electrostatic behavior, and erosion effects during irradiation are required for developing a real prototype assembly. Citation: Instruments PubDate: 2019-04-03 DOI: 10.3390/instruments3020024 Issue No:Vol. 3, No. 2 (2019)
Authors:Pol Ribes-Pleguezuelo, Denis Guilhot, Marta Gilaberte Basset, Erik Beckert, Ramona Eberhardt, Andreas Tünnermann First page: 25 Abstract: 1960 is the birth year of both the laser and the Mars exploration missions. Eleven years passed before the first successful landing on Mars, and another six before the first rover could explore the planet’s surface. In 2011, both technologies were reunited with the first laser landing on Mars as part of the ChemCam instrument, integrated inside the Curiosity Rover. In 2020, two more rovers with integrated lasers are expected to land on Mars: one through the National Aeronautics and Space Administration (NASA) Mars 2020 mission and another through the European Space Agency (ESA) ExoMars mission. The ExoMars mission laser is one of the components of the Raman Spectrometer instrument, which the Aerospace Technology National Institute of Spain (INTA) is responsible for. It uses as its excitation source a laser designed by Monocrom and manufactured in collaboration with the Fraunhofer Institute for Applied Optics and Precision Engineering (IOF). In this paper, we present for the first time the final flight module laser that has been installed in the rover’s onboard laboratory and validated to be shipped to Mars in 2020. Particular emphasis is given to mechanical considerations and assembly procedures, as the ExoMars laser assembly has required soldering techniques in contrast to the standard adhesive technologies used for most laser assembly processes in order to fulfill the environmental and optical requirements of the mission. Citation: Instruments PubDate: 2019-04-19 DOI: 10.3390/instruments3020025 Issue No:Vol. 3, No. 2 (2019)
Authors:Yahav Morag, Yoash Levron First page: 26 Abstract: Wireless power transfer systems based on magnetic induction are usually modeled using the magneto-quasi-static approximation, and by neglecting skin effects and radiation losses. These assumptions imply that the extracted power can grow unlimitedly by increasing frequency or coil size. To bridge this gap, this work proposes general expression for the actual received power of magnetic induction-based energy harvesting transducer, extracting power from a given ambient magnetic field, while accounting for the high-frequency effects. A primary result is that the receiver’s output power is inherently limited by radiation losses at high frequencies and impaired by skin and proximity effects at medium frequencies. The approach provides a design tool for estimating the maximal power that can be delivered through a given transducer, and the optimal operating frequency. Citation: Instruments PubDate: 2019-04-22 DOI: 10.3390/instruments3020026 Issue No:Vol. 3, No. 2 (2019)
Authors:Amin Ghaith, Driss Oumbarek, Charles Kitégi, Mathieu Valléau, Fabrice Marteau, Marie-Emmanuelle Couprie First page: 27 Abstract: The laser plasma accelerator has shown a great promise where it uses plasma wakefields achieving gradients as high as GeV/cm. With such properties, one would be able to build much more compact accelerators, compared to the conventional RF ones, that could be used for a wide range of fundamental research and applied applications. However, the electron beam properties are quite different, in particular, the high divergence, leading to a significant growth of the emittance along the transport line. It is, thus, essential to mitigate it via a strong focusing of the electron beam to enable beam transport. High-gradient quadrupoles achieving a gradient greater than 100 T/m are key components for handling laser plasma accelerator beams. Permanent magnet technology can be used to build very compact quadrupoles capable of providing a very large gradient up to 500 T/m. We present different designs, modeled with a 3D magnetostatic code, of fixed and variable systems. We also review different quadrupoles that have already been built and one design is compared to measurements. Citation: Instruments PubDate: 2019-04-23 DOI: 10.3390/instruments3020027 Issue No:Vol. 3, No. 2 (2019)
Authors:Roman Berner, Yifan Chen, Antonio Ereditato, Patrick P. Koller, Igor Kreslo, David Lorca, Thomas Mettler, Ting Miao, Francesco Piastra, James R. Sinclair, Michael S. Weber First page: 28 Abstract: We present a new technology for the shaping of the electric field in Time Projection Chambers (TPCs) using a carbon-loaded polyimide foil. This technology allows for the minimisation of passive material near the active volume of the TPC and, thus, is capable to reduce background events originating from radioactive decays or scattering on the material itself. Furthermore, the high and continuous electric resistivity of the foil limits the power dissipation per unit area and minimizes the risks of damages in the case of an electric field breakdown. Replacing the conventional field cage with a resistive plastic film structure called “shell” decreases the number of components within the TPC and, therefore, reduces the potential points of failure when operating the detector. A prototype liquid argon (LAr) TPC with such a resistive shell and with a cathode made of the same material was successfully tested for long-term operation with electric field values up to 1 . 6 k V /. The experiment shows that it is feasible to successfully produce and shape the electric field in liquefied noble-gas detectors with this new technology. Citation: Instruments PubDate: 2019-05-09 DOI: 10.3390/instruments3020028 Issue No:Vol. 3, No. 2 (2019)
Authors:Mateusz Sitarz, Jerzy Jastrzębski, Férid Haddad, Tomasz Matulewicz, Katarzyna Szkliniarz, Wiktor Zipper First page: 29 Abstract: In this work, we present an attempt to estimate the reaction excitation function based on the measurements of thick target yield. We fit a function to experimental data points and then use three fitting parameters to calculate the cross-section. We applied our approach to 43Ca(p,n)43Sc, 44Ca(p,n)44gSc, 44Ca(p,n)44mSc, 48Ca(p,2n)47Sc and 48Ca(p,n)48Sc reactions. A general agreement was observed between the reconstructions and the available cross-section data. The algorithm described here can be used to roughly estimate cross-section values, but it requires improvements. Citation: Instruments PubDate: 2019-05-14 DOI: 10.3390/instruments3020029 Issue No:Vol. 3, No. 2 (2019)
Authors:Sule, Petsiuk, Pearce First page: 30 Abstract: Centrifuges are commonly required devices in medical diagnostics facilities as well as scientific laboratories. Although there are commercial and open source centrifuges, the costs of the former and the required electricity to operate the latter limit accessibility in resource-constrained settings. There is a need for low-cost, human-powered, verified, and reliable lab-scale centrifuges. This study provides the designs for a low-cost 100% 3-D printed centrifuge, which can be fabricated on any low-cost RepRap-class (self-replicating rapid prototyper) fused filament fabrication (FFF)- or fused particle fabrication (FPF)-based 3-D printer. In addition, validation procedures are provided using a web camera and free and open source software. This paper provides the complete open source plans, including instructions for the fabrication and operation of a hand-powered centrifuge. This study successfully tested and validated the instrument, which can be operated anywhere in the world with no electricity inputs, obtaining a radial velocity of over 1750 rpm and over 50 N of relative centrifugal force. Using commercial filament, the instrument costs about U.S. $25, which is less than half of all commercially available systems. However, the costs can be dropped further using recycled plastics on open source systems for over 99% savings. The results are discussed in the context of resource-constrained medical and scientific facilities. Citation: Instruments PubDate: 2019-05-18 DOI: 10.3390/instruments3020030 Issue No:Vol. 3, No. 2 (2019)
Authors:Türker, Yağcı, Salman, Çınar, Eken, Bek First page: 31 Abstract: Interest in laser crystallization (LC) of silicon (Si) thin films has been on the rise in fabrication of polycrystalline silicon (pc-Si) based thin/ultrathin photovoltaic solar cells and Si based thin film transistors (TFT). Laser based fabrication of device quality pc-Si thin films at room temperature is expected to be a key enabling technology because of its low energy, material and process time budget. Fabrication of high-quality pc-Si thin films without pre-/post-treatment at large is a disruptive technology which has the potential to revolutionize the Si thin film industry. We hereby describe in detail a multi-wavelength laser processing platform specially developed for crystallization of amorphous silicon (a-Si) thin films into pc-Si thin films. The platform has three main stages. The first stage consists of a nanosecond pulsed ytterbium (Yt3+) doped fibre-laser with a master oscillator power amplifier architecture, operating at a wavelength of 1064 nm with an adjustable repetition rate between 80 kHz–300 kHz. The output beam has a maximum power of 18 W with a pulse energy of 90 µJ. The pulse durations can be set to values between 15 ns–40 ns. The second stage has free-space optical elements for second harmonic generation (SHG) which produces an emission at a wavelength of 532 nm. Conversion efficiency of the SHG is 25% with an output pulse energy of 20 µJ. The platform provides two wavelengths at either 1064 nm or 532 nm in crystallization of a-Si films for different crystallization regimes. The last stage of the platform has a sample processing assembly with a line-focus, which has an x-y motorized stage on a vibration isolated table. Speed of the motorized stage can be set between 1 mm/s–100 mm/s. Stage speed and repetition rate adjustments help to adjust overlap of successive pulses between 97.22%–99.99%. Our platform has variety of tune parameters that make it a uniquely flexible system for delicate Si thin film crystallization. A large selection of operational parameter combinations, the wavelength selection and simultaneous x-y scanning capability allow users to crystallize Si films on various substrates optimally. The operation wavelength choice can be done by considering optical absorption and thickness of a-Si films on different types of substrates. Hence, delivering precise amount of absorbed energy in the line-focus irradiation is useful in increasing the average size of crystalline domains; moreover, nucleation of crystallites can be initiated either from the top or bottom interface of the film. Continuous and simultaneous motion of the stage in two dimensions allows to process arbitrary continuous pc-Si geometries in a-Si film. In summary, our multi-wavelength laser processing platform offers all-in-one LC utility for intricate LC-Si processing. Citation: Instruments PubDate: 2019-06-05 DOI: 10.3390/instruments3020031 Issue No:Vol. 3, No. 2 (2019)
Authors:Federica Mingrone, Marco Calviani, Claudio Torregrosa Martin, Oliver Aberle, Michael Bacak, Enrico Chiaveri, Elvis Fornasiere, Antonio Perillo-Marcone, Vasilis Vlachoudis, the n_TOF Collaboration First page: 32 Abstract: A neutron radiography testing station has been developed exploiting the neutron beam of CERN’s n_TOF Experimental Area 2, located at the shortest distance to the neutron producing-target. The characteristics of the n_TOF neutron beam for the imaging setup are presented in this paper, together with the obtained experimental results. The results focused on the testing of several particle producing targets, including a spent antiproton production targets as well as targets from two different HiRadMat’s experiments. The possible developments of neutron imaging capabilities of the n_TOF facility in terms of detection-systems and beam-line upgrades are as well outlined. Citation: Instruments PubDate: 2019-06-12 DOI: 10.3390/instruments3020032 Issue No:Vol. 3, No. 2 (2019)
Authors:Konrad P. Nesteruk, Luca Ramseyer, Tommaso S. Carzaniga, Saverio Braccini First page: 4 Abstract: Accurate knowledge of the beam energy distribution is crucial for particle accelerators, compact medical cyclotrons for the production of radioisotopes in particular. For this purpose, a compact instrument was developed, based on a multi-leaf Faraday cup made of thin aluminum foils interleaved with plastic absorbers. The protons stopping in the aluminum foils produce a measurable current that is used to determine the range distribution of the proton beam. On the basis of the proton range distribution, the beam energy distribution is assessed by means of stopping-power Monte Carlo simulations. In this paper, we report on the design, construction, and testing of this apparatus, as well as on the first measurements performed with the IBA Cyclone 18-MeV medical cyclotron in operation at the Bern University Hospital. Citation: Instruments PubDate: 2019-01-04 DOI: 10.3390/instruments3010004 Issue No:Vol. 3, No. 1 (2019)
Authors:Dave Prevost, Keerthi Jayamanna, Linda Graham, Sam Varah, Cornelia Hoehr First page: 5 Abstract: Cyclotrons are an important tool for accelerator sciences including the production of medical isotopes for imaging and therapy. For their successful and cost-efficient operation, the planned and unplanned down time of the cyclotron needs to be kept at a minimum without compromising reliability. One of the often required maintenance activities is the replacement of the filament in the ion source. Here, we are reporting on a new ion source filament tested on a medical cyclotron and its prolonging effect on the ion source operation. Citation: Instruments PubDate: 2019-01-16 DOI: 10.3390/instruments3010005 Issue No:Vol. 3, No. 1 (2019)
Authors:Mateusz Sitarz, Etienne Nigron, Arnaud Guertin, Férid Haddad, Tomasz Matulewicz First page: 7 Abstract: The production of 97Ru, a potential Single Photon Emission Computed Tomography (SPECT) radioisotope, was studied at ARRONAX. The cross-section of natMo(α,x)97Ru reaction was investigated in the range of 40–67 MeV irradiating the natMo and Al stacked-foils. The activities of 97Ru and other radioactive contaminants were measured via gamma spectroscopy technique. A global good agreement is observed between obtained cross-section results, previously reported values and TENDL-2017 predictions. Additionally, Radionuclide Yield Calculator, a software that we made available for free, dedicated to quickly calculate yields and plan the irradiation for any radioisotope production, was introduced. The yield of investigated nuclear reactions indicated the feasibility of 97Ru production for medical applications with the use of α beam and Mo targets opening the way to a theranostic approach with 97Ru and 103Ru. Citation: Instruments PubDate: 2019-01-22 DOI: 10.3390/instruments3010007 Issue No:Vol. 3, No. 1 (2019)
Authors:Johanna Peeples, Sang-Hyon Chu, James P. O’Neil, Mustafa Janabi, Bruce Wieland, Matthew Stokely First page: 8 Abstract: Boron nitride nanotubes (BNNTs) were investigated as a target media for cyclotron production of 11C for incident beam energy at or below 11 MeV. Both the 11B(p,n)11C and 14N(p,α)11C nuclear reactions were utilized. A sweep gas of nitrogen or helium was used to collect recoil escape atoms with a desired form of 11CO2. Three prototype targets were tested using an RDS-111 cyclotron. Target geometry and density were shown to impact the saturation yield of 11C and percent of yield recovered as carbon dioxide. Physical damage to the BNNT target media was observed at beam currents above 5 μA. Additional studies are needed to identify operating conditions suitable for commercial application of the method. Citation: Instruments PubDate: 2019-01-27 DOI: 10.3390/instruments3010008 Issue No:Vol. 3, No. 1 (2019)
Authors:Martin Kreller, Hans Jürgen Pietzsch, Martin Walther, Henrik Tietze, Peter Kaever, Torsten Knieß, Frank Füchtner, Jörg Steinbach, Stephan Preusche First page: 9 Abstract: A new Center for Radiopharmaceutical Cancer Research was established at the Helmholtz-Zentrum Dresden-Rossendorf in order to centralize radionuclide production, radiopharmaceutical production and the chemical and biochemical research facilities. The newly installed cyclotron is equipped with two beamlines, two target selectors and several liquid, gas and solid target systems. The cyclotron including the target systems and first results of beam characterization measurements as well as results of the radionuclide production are presented. The produced radionuclides are automatically distributed from the targets to the destination hot cells. This process is supervised and controlled by an in-house developed system. Citation: Instruments PubDate: 2019-01-30 DOI: 10.3390/instruments3010009 Issue No:Vol. 3, No. 1 (2019)
Authors:Stefan Zeisler, Alan Limoges, Joel Kumlin, Jonathan Siikanen, Cornelia Hoehr First page: 10 Abstract: Gallium-68 is a popular radioisotope for positron emission tomography. To make gallium-68 more accessible, we developed a new solid target for medical cyclotrons. Fused zinc targets promise a new, efficient, and reliable technique without the downsides of other commonly used time-consuming methods for solid target fabrication, such as electroplating and sputtering. We manufactured targets by fusing small pressed zinc pellets into a recess in aluminum backings. Using a simple hotplate, the fusing could be accomplished in less than two minutes. Subsequently, the targets were cooled, polished, and used successfully for test irradiations at Ep = 12.8 MeV and up to 20 µA proton current. Citation: Instruments PubDate: 2019-02-01 DOI: 10.3390/instruments3010010 Issue No:Vol. 3, No. 1 (2019)
Authors:William Z. Gelbart, Richard R. Johnson First page: 11 Abstract: In solid targets for radioisotope production, the parent materials—mostly metallic—are usually attached to a substrate (metal part, often copper or silver) to support it during handling and irradiation and to facilitate liquid or gas cooling to remove the heat generated by the particle beam. This cladding process is most frequently done by electroplating. One of the biggest challenges of preparing solid, high-current, 100Mo targets is the difficulty of cladding the substrate with molybdenum—metal that cannot be electroplated. A number of cladding techniques are used with varying degrees of complexity, success, and cost. A simple cladding process, especially suitable for the production of radioisotope targets, was developed. The process uses a metal slurry (metal powder and binder) painted on the substrate and heated in a hydrogen atmosphere where the metal is sintered and diffusion-bound to the substrate in a single step. Citation: Instruments PubDate: 2019-02-02 DOI: 10.3390/instruments3010011 Issue No:Vol. 3, No. 1 (2019)
Authors:Sun Chan, David Cryer, Roger I. Price First page: 12 Abstract: A 3D-printed metal solid target using additive manufacturing process is a cost-effective production solution to complex and intricate target design. The initial proof-of-concept prototype solid target holder was 3D-printed in cast alloy, Al–7Si–0.6Mg (A357). However, given the relatively low thermal conductivity for A357 (κmax, 160 W/m·K), replication of the solid target holder in sterling silver (SS925) with higher thermal conductivity (κmax, 361 W/m·K) was investigated. The SS925 target holder enhances the cooling efficiency of the target design, thus achieving higher target current during irradiation. A validation production of 64Cu using the 3D-printed SS925 target holder indicated no loss of enriched 64Ni from proton bombardment above 80 µA, at 11.5 MeV. Citation: Instruments PubDate: 2019-02-02 DOI: 10.3390/instruments3010012 Issue No:Vol. 3, No. 1 (2019)
Authors:Aleksey B. Rogov First page: 13 Abstract: This paper describes a design approach to a control system of power supply for high-voltage electrochemical processes such as plasma electrolytic oxidation (PEO) or high-voltage anodising (HVA), which require alternating polarisation pulses up to 750 V and a typical current density of 50–500 mA/cm2. Complex characteristics of the electrochemical system response on applied polarisations (positive or negative) cause necessity of precise control of polarising pulse shapes for better process operation and its understanding. A device performs cycle-by-cycle pulse-width modulation (PWM) control, including feedback based on digital analysis of the instantaneous current and/or voltage output, and the desired pulse waveform stored in memory for each output polarity. The output stage has four states corresponding to positive or negative pulses, as well as open- or short-circuit conditions, with respect to an electrochemical cell. A fully programmable controller allows one to generate arbitrary waveforms, as well as their sequences, by means of “regime designer” software. Moreover, a smart feedback system can provide adaptation of the next pulse parameter from analysis of the process prehistory. For instance, this approach allows one to separate main electrochemical process (coating formation) and diagnosis of the phenomenon through introduction of high-voltage triangular voltage sweep pulse within a pause of the main process, which is normally carried out under a current control. Citation: Instruments PubDate: 2019-02-07 DOI: 10.3390/instruments3010013 Issue No:Vol. 3, No. 1 (2019)
Authors:William Z. Gelbart, Richard R. Johnson First page: 14 Abstract: A significant number of medical radioisotopes use solid, often metallic, parent materials. These materials are deposited on a substrate to facilitate the cooling and handling of the target during placing, irradiation, and processing. The processing requires the transfer of the target to a processing area outside the irradiation area. In this new approach the target is processed at the irradiation site for liquid only transport of the irradiated target material to the processing area. The design features common to higher energy production target systems are included in the target station. The target is inclined at 14 degrees to the beam direction. The system has been designed to accept an incident beam of 15 to 16 mm diameter and a beam power between 2 and 5 kW. Thermal modeling is presented for targets of metals and compounds. A cassette of five or 10 prepared targets is housed at the target station as well as a target dissolution assembly. Only the dissolved target material is transported to the chemistry laboratory so that the design does not require additional irradiation area penetrations. This work presents the design, construction, and modeling details of the assembly. A full performance characterization will be reported after the unit is moved to a cyclotron facility for beam related measurements. Citation: Instruments PubDate: 2019-02-11 DOI: 10.3390/instruments3010014 Issue No:Vol. 3, No. 1 (2019)
Authors:Fabio Acerbi, Giovanni Paternoster, Massimo Capasso, Marco Marcante, Alberto Mazzi, Veronica Regazzoni, Nicola Zorzi, Alberto Gola First page: 15 Abstract: Silicon photomultipliers (SiPMs) are single-photon sensitive solid-state detectors that are becoming popular for several applications, thanks to massive performance improvements over the last years. Starting as a replacement for the photomultiplier tube (PMT), they are now used in medical applications, big high-energy physics experiments, nuclear physics experiments, spectroscopy, biology and light detection and ranging (LIDAR) applications. Due to different requirements in terms of detection efficiency, noise, etc., several optimizations have been introduced by the manufacturers; for example, spectral sensitivity has been optimized for visible light, near ultraviolet, vacuum ultraviolet, and near infrared light. Each one of them require specific processes and structural optimization. We present in this paper recent improvements in SiPM performance, owing to a higher cell fill-factor, lower noise, improved silicon materials, and deep trench isolation. We describe issues related to the characterization of analog SiPM, particularly due to the different sources of correlated noise, which have to be distinguished from each other and from the primary pulses. We also describe particular analyses and optimizations conducted for specific applications like the readout of liquid noble gas scintillators, requiring these detectors to operate at cryogenic temperatures. Citation: Instruments PubDate: 2019-02-12 DOI: 10.3390/instruments3010015 Issue No:Vol. 3, No. 1 (2019)
Authors:Stefan Zeisler, Benjamin Clarke, Joel Kumlin, Brian Hook, Samuel Varah, Cornelia Hoehr First page: 16 Abstract: A new solid target system for the TRIUMF TR13 cyclotron that can accommodate target discs with a 1-2-mm thickness and a 28-mm diameter has been developed. The target system design is based on a modified clamping mechanism of a KF-40 vacuum connector, and comprises an easy and quick ejection mechanism for the target plate. The new quick-release target system decreases the retrieval time of the irradiated target to less than 1 minute and is expected to reduce the radiation burden to operating staff by a factor of ~10. Citation: Instruments PubDate: 2019-02-12 DOI: 10.3390/instruments3010016 Issue No:Vol. 3, No. 1 (2019)
Authors:Hanna Skliarova, Paolo Buso, Sara Carturan, Carlos Rossi Alvarez, Sara Cisternino, Petra Martini, Alessandra Boschi, Juan Esposito First page: 17 Abstract: A closed-loop technology aiming at recycling the highly 100Mo-enriched molybdenum target material has been developed in the framework of the international research efforts on the alternative, cyclotron-based 99mTc radionuclide production. The main procedure steps include (i) 100Mo-based target manufacturing; (ii) irradiation under proton beam; (iii) dissolution of 100Mo layer containing 9×Tc radionuclides (produced by opened nuclear reaction routes) in concentrated H2O2 solution; and (iv) Mo/Tc separation by the developed radiochemical module, from which the original 100Mo comes as the “waste” alkaline aqueous fraction. Conversion of the residual 100Mo molybdates in this fraction into molybdic acids and MoO3 has been pursued by refluxing in excess of HNO3. After evaporation of the solvent to dryness, the molybdic acids and MoO3 may be isolated from NaNO3 by exploiting their different solubility in water. When dried in vacuum at 40 °C, the combined aqueous fractions provided MoO3 as a white powder. In the last recovery step MoO3 has been reduced using a temperature-controlled reactor under hydrogen overpressure. An overall recovery yield of ~90% has been established. Citation: Instruments PubDate: 2019-02-13 DOI: 10.3390/instruments3010017 Issue No:Vol. 3, No. 1 (2019)
Authors:Andrew K.H. Robertson, Andrew Lobbezoo, Louis Moskven, Paul Schaffer, Cornelia Hoehr First page: 18 Abstract: With recent impressive clinical results of targeted alpha therapy using 225Ac, significant effort has been directed towards providing a reliable and sufficient supply of 225Ac to enable widespread using of 225Ac-radiopharmaceuticals. TRIUMF has begun production of 225Ac via spallation of thorium metal with 480 MeV protons. As part of this program, a new 225Ac-production target system capable of withstanding the power deposited by the proton beam was designed and its performance simulated over a range of potential operating parameters. Special attention was given to heat transfer and stresses within the target components. The target was successfully tested in two irradiations with a 72–73 µA proton beam for a duration of 36.5 h. The decay corrected activity at end of irradiation (average ± standard deviation) was (524 ± 21) MBq (14.2 mCi) and (86 ± 13) MBq (2.3 mCi) for 225Ac and 225Ra, respectively. These correspond to saturation yields of 72.5 MBq/µA for 225Ac and 17.6 MBq/µA for 225Ra. Longer irradiations and production scale-up are planned in the future. Citation: Instruments PubDate: 2019-02-15 DOI: 10.3390/instruments3010018 Issue No:Vol. 3, No. 1 (2019)
Authors:Saverio Braccini, Tommaso Carzaniga, Giulia Pisegna, Paola Scampoli First page: 19 Abstract: The possibility of performing proton radiography by using the proton angular spread due to Coulomb multiple scattering was investigated, for the first time, with an emulsion film detector. Two different phantoms were irradiated with the therapeutic proton beam at the Paul Scherrer Institut (PSI) in Villigen, Switzerland. The first one is a simple polymethylmethacrylate (PMMA) block having two different thicknesses (4 cm and 3 cm), and the second one is a PMMA cube with five aluminum rods embedded along a diagonal. Only one emulsion film was needed to perform the radiography, an important issue as the analysis of this kind of detector is time-consuming. Furthermore, the method showed an enhanced contrast when high atomic-number materials are traversed. This gives an advantage, when compared to proton range radiography. Citation: Instruments PubDate: 2019-02-17 DOI: 10.3390/instruments3010019 Issue No:Vol. 3, No. 1 (2019)
Authors:Sergio J.C. do Carmo, Pedro M. de Oliveira, Francisco Alves First page: 20 Abstract: This work presents a simple method for determining the energy of the proton beam in biomedical cyclotrons, using no additional experimental set-up and only materials from radioisotope routine productions that are therefore available on-site. The developed method requires neither absolute efficiency calibration nor beam current measurements, thus avoiding two major sources of uncertainty. Two stacks composed of natural titanium thin foils, separated by an energy degrader of niobium, were mounted in a commercial target and irradiated. The resulting activities of 48V were assessed by a HPGe spectrometer. Citation: Instruments PubDate: 2019-03-05 DOI: 10.3390/instruments3010020 Issue No:Vol. 3, No. 1 (2019)
Authors:Hanna Skliarova, Sara Cisternino, Gianfranco Cicoria, Mario Marengo, Emiliano Cazzola, Giancarlo Gorgoni, Vincenzo Palmieri First page: 21 Abstract: 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. Citation: Instruments PubDate: 2019-03-13 DOI: 10.3390/instruments3010021 Issue No:Vol. 3, No. 1 (2019)
Authors:Helmut Burkhardt First page: 22 Abstract: Dedicated high-beta optics are used to make forward proton scattering measurements possible at the LHC. Following a short general introduction and history of special high-beta optics and running conditions, we describe the two types of special high-beta runs planned for 2018. A run at top energy at β y * = 90 m for elastic and diffractive scattering, and a low energy run to measure the rho-parameter in the Coulomb interference region. Citation: Instruments PubDate: 2019-03-18 DOI: 10.3390/instruments3010022 Issue No:Vol. 3, No. 1 (2019)
Authors:Joseph Pearson, Helmut Cölfen First page: 23 Abstract: Open-source Multiwavelength Analytical Ultracentrifugation (MWL-AUC) detection systems have been evolving for over a decade. Continual advances emerging out of several research groups have brought the instrumentation technology to increasingly higher levels of performance. The capabilities of MWL-AUC have been documented in many publications, demonstrating the applicability of broad spectrum absorbance acquisitions in analytical ultracentrifugation to a wide array of scientific fields. Despite numerous examples of the usefulness and unique advantages of MWL-AUC, the adoption of the technology by more research groups has been slow. The complexity of the hardware, integration within an ultracentrifuge platform and lack of practical construction and operational information is the likely source of reluctance. Here, we clearly describe the challenges facing a researcher considering adopting MWL-AUC technology in their own laboratories, and provide the information necessary to implement and operate a MWL-AUC system. The discussion includes details of detector assembly, optical alignment, and acquisition parameter settings necessary to achieve high quality experimental results. Citation: Instruments PubDate: 2019-03-21 DOI: 10.3390/instruments3010023 Issue No:Vol. 3, No. 1 (2019)
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