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

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21220%2F23%3A00370755" target="_blank" >RIV/68407700:21220/23:00370755 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1016/j.vacuum.2022.111656" target="_blank" >https://doi.org/10.1016/j.vacuum.2022.111656</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.vacuum.2022.111656" target="_blank" >10.1016/j.vacuum.2022.111656</a>

Jazyk výsledku

angličtina

Název v původním jazyce

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

Popis výsledku v původním jazyce

In the superconducting magnets of the Large Hadron Collider (LHC) at CERN, most of the beam-induced heat load is intercepted by a beam-screen (BS) cryogenically cooled to 5-20 K. When circulating the bunched proton beam, an electron cloud (EC) can form and bombard the BS copper surface with high doses of predominantly low-energy electrons, which desorb gas and consequently increase the pressure. The beam-induced pressure rise decreases during operation as the electron irradiation diminishes the secondary electron yield (SEY) and the electron-stimulated desorption (ESD) yield, a phenomenon referred to as 'beam conditioning'. Low ESD and SEY values achieved rapidly are requisite to mitigate EC and maintain UHV in storage rings. We report data on ESD and SEY electron conditioning completed at cryogenic temperature with 0-1 keV electrons up to an electron dose of 5.10-3 C mm-2. Our results show that SEY conditioning depends on the primary electron energy and also that ESD yield significantly decreases with temperature. At 15 K, the amorphous-carbon coating and laser-treated copper present SEY below 1.1 and have initial ESD yields 3-6 times lower than OFE copper. Our results conform to the SEY and ESD's general understanding and extend it towards cryogenic temperatures.

Název v anglickém jazyce

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

Popis výsledku anglicky

In the superconducting magnets of the Large Hadron Collider (LHC) at CERN, most of the beam-induced heat load is intercepted by a beam-screen (BS) cryogenically cooled to 5-20 K. When circulating the bunched proton beam, an electron cloud (EC) can form and bombard the BS copper surface with high doses of predominantly low-energy electrons, which desorb gas and consequently increase the pressure. The beam-induced pressure rise decreases during operation as the electron irradiation diminishes the secondary electron yield (SEY) and the electron-stimulated desorption (ESD) yield, a phenomenon referred to as 'beam conditioning'. Low ESD and SEY values achieved rapidly are requisite to mitigate EC and maintain UHV in storage rings. We report data on ESD and SEY electron conditioning completed at cryogenic temperature with 0-1 keV electrons up to an electron dose of 5.10-3 C mm-2. Our results show that SEY conditioning depends on the primary electron energy and also that ESD yield significantly decreases with temperature. At 15 K, the amorphous-carbon coating and laser-treated copper present SEY below 1.1 and have initial ESD yields 3-6 times lower than OFE copper. Our results conform to the SEY and ESD's general understanding and extend it towards cryogenic temperatures.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Projekt

—

Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2023

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Vacuum

ISSN

0042-207X

e-ISSN

1879-2715

Svazek periodika

207

Číslo periodika v rámci svazku

january

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

8

Strana od-do

1-8

Kód UT WoS článku

000885990100001

EID výsledku v databázi Scopus

2-s2.0-85141497826