Investigations on Caesium Dispersion and Molybdenum Coating on SPIDER Components

Candela, Valentina; Cavallini, C.; Gasparrini, Claudia; Armelao, Lidia; Candeloro, V.; Palma, M. Dalla; Fadone, M.; Marcuzzi, D.; Pavei, M.; Pepato, A.; Duteil, Basile Pouradier; Rancan, Marzio; Rizzolo, A.; Sartori, E.; Segalini, B.; Serianni, G.; Spolaore, M.; Zorzi, Federico; Sonato, P.

doi:10.3390/ma16010206

Cited by 4 publications

(6 citation statements)

References 15 publications

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“…While operating SPIDER in short pulses, it was found that the characteristics of the caesium flux from the caesium delivery system between plasma discharges was of great importance and could affect the beam uniformity and the capability of the plasma to redistribute the caesium [4]. Caesium distribution was studied density during operation [15,16], as well as after the end of the operations with visual inspections and analyses of the ion source walls [17,18]. It was found that the oven nozzle evaporated the largest caesium amount onto the surfaces in the proximity of the nozzle, creating stains that were clearly visible once the source was opened.…”

Section: Control Of Caesium Evaporation and Improvement Of The Emissi...mentioning

confidence: 99%

Highlights of recent SPIDER results and improvements

Sartori,

Agnello,

Agostini

et al. 2023

J. Inst.

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Three years of experiments on SPIDER allowed characterization of the main features of the source plasma and of the negative ion beam, in the original design configuration. For the large dimensions of the source chamber, and of the extraction area, the investigation of the single-beamlet currents and of the source plasma uniformity had to be carried out to extend the knowledge gained in smaller prototype sources. The configuration of the multiple RF drivers and filter field topologies were found to cause a peculiar behavior in the plasma confinement in the drivers, creating left-right asymmetries which were also visible in the extracted negative ion currents, even after the early implementation of a new scheme of plasma-grid current send and return busbars that greatly improved performance at high filter fields. The plasma properties in the driver and expansion region as well as the positive ion energy at the extraction region were studied in different experimental conditions, and interpreted also with the support of numerical models, suggesting that an improved plasma confinement could contribute to the increase of the plasma density, and to a certain extent to a lowering of the plasma potential profile; both effects shall contribute to increase the presence of cold negative ions for the formation of low-divergence beamlets. Early results related to unwanted RF discharges on the back of the plasma source and the gas conductance of the beam source suggested the reduction of the vessel pressure as mitigation, leading to the definition of a new pumping system. The difficulties related to the simultaneous operation, stable control and high-power operation of multiple RF self-oscillating vacuum tube based RF generators were an unambiguous obstruction to the experimentation, calling for the implementation of RF solid-state amplifiers. The initial tests related to caesium management, the non-uniform plasma properties at different locations across the plasma grid, and the challenges in the measurement of the current and divergence of the accelerated beamlet, unambiguously resulted in the need of new diagnostic systems to investigate with better resolution the spatial uniformities. This contribution summarises how the main experimental findings in the previous experimental campaigns are driving modifications to the SPIDER experiment, during the present shut down, in view of future operations.

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Section: Control Of Caesium Evaporation and Improvement Of The Emissi...mentioning

confidence: 99%

Highlights of recent SPIDER results and improvements

Sartori,

Agnello,

Agostini

et al. 2023

J. Inst.

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show abstract

“…Energy can be transferred between a solid surface and a gas or between two or more surfaces. Radiation can be expressed in the following equation (10). where 'Q' is the heat transfer rate (W), 'A' is the surface area (m 2 ), ''' is the Stefan-Boltzmann constant (5.669 X 10 -8 W/m 2 ᆞ K 4 ), 'Tw' is the surface temperature of the material (K), and 'T∞' is the atmospheric temperature (K)…”

Section: ∆Y=ytreated-yuntreatedmentioning

confidence: 99%

“…The surface temperature was determined according to the above conduction, convection, and radiation theories, assuming a steady state with no time-induced temperature difference. The heat transfer rate calculated by this research model was derived through the above e equations ( 8)- (10), and presented again in equation (11).…”

Section: ∆Y=ytreated-yuntreatedmentioning

confidence: 99%

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Research on Heat transfer and IR Characteristics of Molybdenum Sputtered Polyamide Materials

Han¹

2023

Preprint

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Demand for development of the convergence industry, research studies on electrical conductivity, thermal characteristics, semiconductors, motors, and batteries using special materials have come to the fore. Meanwhile, molybdenum (Mo) exhibits relatively small inorganic qualities, and the thermal conductivity rate is applied to various fields. In this study, in-depth characteristics were considered regarding the concentration of thermal characteristics, IR car terminal characteristics, and IR ve-hicles. This study calculated each phase temperature of the molybdenum sputtered specimens in the steady state according to the heat transfer theory. When the molybdenum-sputtered fabric’s metal layer pointed to the outside air, the heat transfer rate (Q) was high at 5748.3W, In contrast, if the molybdenum sputtered film’s metal layer of the pointed toward the heat source, the heat transfer rate (Q) was low at 187.1W. As a result of measuring the IR transmittance, the infrared transmit-tance of the molybdenum sputtering-treated sample was significantly reduced compared to the untreated sample. In the case of untreated samples, the transmittance ranged from 92.7 to 42.0%. When only the cross part was treated with molybdenum sputtering and the molybdenum surface was directed toward the IR irradiator, the IR transmittance was 66.8~0.7%. It is believed that the molybdenum sputtering polyamide samples produced in this study can be applied to multifunc-tional military wear, biosignal detection sensors, semiconductor products, batteries, etc., by utilizing excellent electrical properties, stealth functions, IR blocking properties, and lightness for infrared thermal imaging detectors.

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“…Molybdenum has been examined in various studies focused on molybdenum carbide, electron spin resonance, catalytic production, molybdenum disulfide nanosheets, molybdenum disulfide photodetectors, solar energy applications, electrocatalysts, etc. [1][2][3][4][5][6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Research on IR and Heat Transfer Characteristics of Molybdenum-Sputtered Polyamide Materials

Han

2023

Coatings

View full text Add to dashboard Cite

Demand for the development of the convergence industry, research studies on heat transfer, thermal characteristics, semiconductors, motors, and batteries using special materials have come to the fore. Meanwhile, molybdenum (Mo) exhibits relatively small inorganic qualities, and the thermal conductivity rate is applied to various fields. In this study, in-depth characteristics were considered regarding the concentration of thermal characteristics and IR characteristics. In particular, this study conducted a thicker molybdenum layer sputtering work than previous studies and examined it in detail at high temperatures by pore size. This study calculated each phase temperature of the molybdenum-sputtered specimens in the steady state according to the heat transfer theory. When the molybdenum-sputtered fabric’s metal layer pointed to the outside air, the heat transfer rate (Q) was high at 5748.3 W. In contrast, if the molybdenum-sputtered film’s metal layer pointed toward the heat source, the heat transfer rate (Q) was low at 187.1 W. As a result of measuring the IR transmittance, the infrared transmittance of the molybdenum-sputtering-treated sample was significantly reduced compared to the untreated sample. It is believed that the molybdenum-sputtering polyamide samples produced in this study can be applied to multifunctional military wear, biosignal detection sensors, semiconductor products, batteries, etc., by utilizing excellent electrical properties, stealth functions, and IR-blocking properties.

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Investigations on Caesium Dispersion and Molybdenum Coating on SPIDER Components

Cited by 4 publications

References 15 publications

Highlights of recent SPIDER results and improvements

Highlights of recent SPIDER results and improvements

Research on Heat transfer and IR Characteristics of Molybdenum Sputtered Polyamide Materials

Research on IR and Heat Transfer Characteristics of Molybdenum-Sputtered Polyamide Materials

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