Collector-based measurement of gas desorption and secondary electron emission induced by 0–1.4 keV electrons from LHC-grade copper at 15 K

Haubner, Michal; Baglin, V.; Henrist, B.

doi:10.1016/j.nimb.2022.09.013

Cited by 3 publications

(9 citation statements)

References 37 publications

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“…The experimental setup aims to reproduce in a controlled way the relevant HL-LHC conditions (UHV, temperature below 20 K, unbaked sample) of its cryogenic system and to study the ESD and SEY. Detailed technical description is given in a dedicated paper [63], so only briefly (see Fig. 1).…”

Section: Methodsmentioning

confidence: 99%

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Electron conditioning of technical surfaces at cryogenic and room temperature in the 0–1 keV energy range

Haubner

Baglin

Henrist

2023

Vacuum

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Section: Methodsmentioning

confidence: 99%

“…Schematized arrangement for SEY and electron desorption measurements in the 0-1 keV region. See the text and Ref [63].…”

mentioning

confidence: 99%

Electron conditioning of technical surfaces at cryogenic and room temperature in the 0–1 keV energy range

Haubner

Baglin

Henrist

2023

Vacuum

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“…A newly developed analytical system was used to acquire the SEY and ESD data. The corresponding methodology for cryogenic measurements was described in detail in preceding articles [36,37].…”

Section: Experimental Techniques 231 Experimental Setupmentioning

confidence: 99%

“…In an ESD energy dependence measurement, the data points are spaced at 1 eV in the low-energy region and up to 300 eV around 0-1 keV. The beam current of ∼2 µA is sufficient to create a measurable pressure rise on the QMS, but low enough not to significantly damage the sample, as discussed in [36].…”

Section: Esd Measurementmentioning

confidence: 99%

“…Secondly, similar to technical-grade metals, the SEY of a REBCO-CC sample decreases under 300 eV of electron irradiation, a phenomenon known as electron conditioning. As most UHV-cleaned metal surfaces exhibit high SEY in their as-received air-exposed states [36,37], they typically condition during electron irradiation to reach SEY values at around 1, which are low enough to prevent electron multipacting.…”

Section: Secondary Electron Yieldmentioning

confidence: 99%

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Electron Beam Characterization of REBCO-Coated Conductors at Cryogenic Conditions

et al. 2023

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Particle accelerators with superconducting magnets operating at cryogenic temperatures use a beam screen (BS) liner that extracts heat generated by the circulating bunched charge particle beam before it can reach the magnets. The BS surface, commonly made of high–conductivity copper, provides a low impedance for beam stability reasons, low secondary electron yield (SEY) to mitigate the electron–cloud (EC) effect, and low electron–stimulated desorption yield (ESD) to limit the dynamic pressure rise due to EC. Rare–earth barium copper oxide (REBCO) high–temperature superconductors (HTSs) recently reached technical maturity, are produced as coated conductor tapes (REBCO–CCs), and will be considered for application in future colliders to decrease the BS impedance and enable operation at around 50 K, consequently relaxing the cryogenic requirements. Aside from HTS properties, industry–grade REBCO–CCs also need qualification for EC and dynamic vacuum compatibility under accelerator–like conditions. Hence, we report the SEY and ESD measured at cryogenic temperatures of 12 K under low–energy electron irradiation of 0–1.4 keV. We also verify the sample compositions and morphologies using the XPS, SEM, and EDS methods. The energy and dose dependencies of ESD are comparable to those of technical–grade metals and one sample reached SEYMAX = 1.2 after electron conditioning.

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Investigation on activation characterization, secondary electron yield, and surface resistance of novel quinary alloy Ti–Zr–V–Hf–Cu non-evaporable getters

Yigit,

Wang,

et al. 2024

Review of Scientific Instruments

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The performance of next-generation particle accelerators has been adversely affected by the occurrence of electron multipacting and vacuum instabilities. Particularly, minimization of secondary electron emission (SEE) and reduction of surface resistance are two critical issues to prevent some of the phenomena such as beam instability, reduction of beam lifetime, and residual gas ionization, all of which occur as a result of these adverse effects in next-generation particle accelerators. For the first time, novel quinary alloy Ti–Zr–V–Hf–Cu non-evaporable getter (NEG) films were prepared on stainless steel substrates by using the direct current magnetron sputtering technique to reduce surface resistance and SEE yield with an efficient pumping performance. Based on the experimental findings, the surface resistance of the quinary Ti–Zr–V–Hf–Cu NEG films was established to be 6.6 × 10−7 Ω m for sample no. 1, 6.4 × 10−7 Ω m for sample no. 2, and 6.2 × 10−7 Ω m for sample no. 3. The δmax measurements recorded for Ti–Zr–V–Hf–Cu NEG films are 1.33 for sample no. 1, 1.34 for sample no. 2, and 1.35 for sample no. 3. Upon heating the Ti–Zr–V–Hf–Cu NEG film to 150 °C, the XPS spectra results indicated that there are significant changes in the chemical states of its constituent metals, Ti, Zr, V, Hf, and Cu, and these chemical state changes continued with heating at 180 °C. This implies that upon heating at 150 °C, the Ti–Zr–V–Hf–Cu NEG film becomes activated, showing that novel quinary NEG films can be effectively employed as getter pumps for generating ultra-high vacuum conditions.

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Collector-based measurement of gas desorption and secondary electron emission induced by 0–1.4 keV electrons from LHC-grade copper at 15 K

Cited by 3 publications

References 37 publications

Electron conditioning of technical surfaces at cryogenic and room temperature in the 0–1 keV energy range

Electron conditioning of technical surfaces at cryogenic and room temperature in the 0–1 keV energy range

Electron Beam Characterization of REBCO-Coated Conductors at Cryogenic Conditions

Investigation on activation characterization, secondary electron yield, and surface resistance of novel quinary alloy Ti–Zr–V–Hf–Cu non-evaporable getters

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