Secondary-Electron Emission from Molybdenum Due to Positive and Negative Ions of Atmospheric Gases

Mahadevan, Priya; Magnuson, G. D.; Layton, J. K.; Carlston, C. E.

doi:10.1103/physrev.140.a1407

Cited by 62 publications

(19 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For potential emission, a higher ionization energy is expected to give a higher yield, which is consistent with the results in figure 8 since I + has a higher ionization threshold than I + 2 . Similar behavior has been seen previously with atomic and diatomic nitrogen and oxygen ions 33 .…”

Section: Resultssupporting

confidence: 88%

Secondary electron emission due to multi-species iodine ion bombardment of different target materials

Habl

Rafalskyi

Lafleur

2021

Journal of Applied Physics

View full text Add to dashboard Cite

Ion-induced Secondary Electron Emission (SEE) is a fundamental surface interaction that strongly influences many plasma discharges. Recently, interest in iodine plasmas is growing due to new material processing and space propulsion applications, but data for SEE yields due to iodine ion bombardment remains scarce. Additionally, due to the formation of multiple ion species in typical iodine plasmas, and surface chemical reactions leading to iodide layer formation, the effective SEE yield is expected to differ from that for individual ion species on clean surfaces. In this work, we measure the SEE yield of multi-species iodine ion beams bombarding different target materials (Mo, W, Al, Ti, Cu, carbon-carbon, and steel), in the energy range 0.6-1.4 keV. An ion beam is produced by extracting and accelerating ions from a gridded ion source based on an Inductively Coupled Plasma (ICP). SEE yields of downstream targets are measured using a conventional electrostatic probe technique, and the ion beam composition is determined using time-of-flight spectrometry. The beam is composed predominately of atomic (I + ) and molecular (I +2 ) ions whose ratio changes depending on the ICP power. Yields depend strongly on the target material and beam composition, and vary between 0.05-0.4 depending on whether potential or kinetic emission processes dominate.

show abstract

Section: Resultssupporting

confidence: 88%

Secondary electron emission due to multi-species iodine ion bombardment of different target materials

Habl

Rafalskyi

Lafleur

2021

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…where k is the proportionality constant and depends on the apparatus condition, j is the target ion for measurement, I (i) is the intensity of the current for ions j, T is the temperature of Knudsen cell during measuring, σ(i) is the ionization cross-section, γ is the isotope abundance ratio for ions j, S is the relative multiplier gain of the detector for ions j(∝m −1/2 [15]), and ΔE is the difference between the appearance potential for ions j and the electron beam energy for ionizations. The maximum ionization cross-sections, appearance potentials and isotope abundance ratios are listed in Table 3.…”

Section: Methodsmentioning

confidence: 99%

The Evaporation Behavior of Volatile Fission Products in FLiNaK Salt

Taira¹,

Arita²,

Yamawaki³

2017

oajost

View full text Add to dashboard Cite

Molten salt reactor (MSR) was suggested for the one of the nuclear power plant concepts planned for generation IV. However, little study had been done on the severe accident at MSR. The one of the severe accident at MSR is considered that the molten salt with fuel will be exposed to air and some fission products will release to environment. The molten FLiNaK salt (LiF-NaF-KF: 46.5-11.5-42 mol%) with CsI(FLiNaK-CsI : 99-1 mol%) was evaporated and released gases were measured by mass spectrometry. The evaporated gases from above sample were mainly CsI and KI. The value of vapor pressure for CsI was low about ten to the first ∼ second power of vapor pressure for pure CsI at same temperature. Therefore, it is expected that FLiNaK prevents the release of CsI. On the other hand, despite KI were not included in original sample, KI released significantly.

show abstract

“…First, the trends in current vs. voltage for both pure argon and Ar/(10%)O 2 indicate a nearly linear relationship for energies above 1.2 keV (slightly higher in pure argon), before leveling off at low energies. This type of behavior is similar to ion-induced secondary electron yield measurements over energies commensurate with the applied cathode bias [24]. For yield measurements, it is argued that the emission mechanism at low energies will have a contribution from potential effects, which only requires that the incoming ion's ionization potential (E ip ) is at least twice the target work function (ϕ) and thus has no kinetic energy threshold.…”

Section: Cathode Current Vs Applied Voltagementioning

confidence: 59%

Hollow Cathode Produced Electron Beams for Plasma Generation: Cathode Operation in Gas Mixtures

Walton¹,

Leonhardt²,

Fernsler³

2006

View full text Add to dashboard Cite

Standard Form 298 (Rev. 8-98)Prescribed by ANSI Std. Z39.18Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Pulsed hollow cathode discharges, used to generate kilovolt electron beams for the production of plasmas, were studied in low pressure (50-70 mTorr) backgrounds of argon, oxygen, nitrogen, SF 6 and mixtures thereof. Cathode currents were measured as a function of cathode voltage, duty factor, and relative gas concentration. The cathode current was found to have a dependence on all variables, with the greatest impact being operating gas for all voltages and duty factors. The ambient gas is thought to influence the production of secondary electrons at the cathode surface, thereby impacting the operation of the hollow cathode discharge and electron beam production. REPORT TYPE 1. REPORT DATE (DD-MM-YYYY) TITLE AND SUBTITLE AUTHOR(S) PERFORMING ORGANIZATION REPORT NUMBER PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) SPONSOR / MONITOR'S ACRONYM(S) 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) SPONSOR / MONITOR'S REPORT NUMBER(S) 15-12-2006Memorandum Report AbstractPulsed hollow cathode discharges, used to generate kilovolt electron beams for the production of plasmas, were studied in low pressure (50-70 mTorr) backgrounds of argon, oxygen, nitrogen, SF 6 and mixtures thereof. Cathode currents were measured as a function of cathode voltage, duty factor, and relative gas concentration. The cathode current was found to have a dependence on all variables, with the greatest impact being operating gas for all voltages and duty factors. The ambient gas is thought to influence the production of secondary electrons at the cathode surface, thereby impacting the operation of the hollow cathode discharge and electron beam production.

show abstract

Secondary-Electron Emission from Molybdenum Due to Positive and Negative Ions of Atmospheric Gases

Cited by 62 publications

References 7 publications

Secondary electron emission due to multi-species iodine ion bombardment of different target materials

Secondary electron emission due to multi-species iodine ion bombardment of different target materials

The Evaporation Behavior of Volatile Fission Products in FLiNaK Salt

Hollow Cathode Produced Electron Beams for Plasma Generation: Cathode Operation in Gas Mixtures

Contact Info

Product

Resources

About