Collector-based measurement of gas desorption and secondary electron emission induced by 0–1.4 keV electrons from LHC-grade copper at 15 K
نویسندگان
چکیده
• New collector-based setup measures ESD and SEY also at cryogenic temperatures. Highly Oriented Pyrolytic Graphite served as reference to validate measurement. Isotopically traced 15 N 2 was used commission the low-energy Compared 300 eV, 17 eV electrons do limited conditioning of yields. Cryogenic temperature lowers by 5 up 150 times for H CO respectively. CERN’s Large Hadron Collider cryomagnets embed a 1.9 K UHV chamber lined with 5–20 beam-screen (BS) that intercepts synchrotron radiation electron cloud (EC). The low–energy EC irradiates BS desorbs gas, creating dynamic vacuum effect. A novel controllably reproduces this irradiating an unbaked as-received copper sample 0–1.4 keV electrons, representing slice spectrum. This is qualified using HOPG secondary yield (SEY) tracer in stimulated desorption (ESD) measurements. Measurement revealed sub-10 thresholds maximum around 0.18 /e ? 0.13 CO/e . Irradiation 1 ? 8.10 –4 C.mm ?2 conditioned alike. Similar dose only caused minor reduction no decline. yields decreased 5-150x between 265 K, respectively..
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ژورنال
عنوان ژورنال: Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms
سال: 2022
ISSN: ['1872-9584', '0168-583X']
DOI: https://doi.org/10.1016/j.nimb.2022.09.013