Molecular desorption of stainless steel vacuum chambers irradiated with 4.2 MeV/u lead ions
In preparation for the heavy ion program of the Large Hadron Collider at CERN, accumulation and cooling tests with lead ion beams have been performed in the Low Energy Antiproton Ring. These tests have revealed that due to the unexpected large outgassing of the vacuum system, the dynamic pressure of...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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American Physical Society
2003-01-01
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| Series: | Physical Review Special Topics. Accelerators and Beams |
| Online Access: | http://doi.org/10.1103/PhysRevSTAB.6.013201 |
| _version_ | 1819123634573148160 |
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| author | E. Mahner J. Hansen J.-M. Laurent N. Madsen |
| author_facet | E. Mahner J. Hansen J.-M. Laurent N. Madsen |
| author_sort | E. Mahner |
| collection | DOAJ |
| description | In preparation for the heavy ion program of the Large Hadron Collider at CERN, accumulation and cooling tests with lead ion beams have been performed in the Low Energy Antiproton Ring. These tests have revealed that due to the unexpected large outgassing of the vacuum system, the dynamic pressure of the ring could not be maintained low enough to reach the required beam intensities. To determine the actions necessary to lower the dynamic pressure rise, an experimental program has been initiated for measuring the molecular desorption yields of stainless steel vacuum chambers by the impact of 4.2 MeV/u lead ions with the charge states +27 and +53. The test chambers were exposed either at grazing or at perpendicular incidence. Different surface treatments (glow discharges, nonevaporable getter coating) are reported in terms of the molecular desorption yields for H_{2}, CH_{4}, CO, Ar, and CO_{2}. Unexpected large values of molecular yields per incident ion up to 2×10^{4} molecules/ion have been observed. The reduction of the ion-induced desorption yield due to continuous bombardment with lead ions (beam cleaning) has been investigated for five different stainless steel vacuum chambers. The implications of these results for the vacuum system of the future Low Energy Ion Ring and possible remedies to reduce the vacuum degradation are discussed. |
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| id | doaj.art-0486643c2cd743b59921cccc0a0c46bd |
| institution | Directory Open Access Journal |
| issn | 1098-4402 |
| language | English |
| last_indexed | 2024-12-22T07:11:28Z |
| publishDate | 2003-01-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review Special Topics. Accelerators and Beams |
| spelling | doaj.art-0486643c2cd743b59921cccc0a0c46bd2022-12-21T18:34:31ZengAmerican Physical SocietyPhysical Review Special Topics. Accelerators and Beams1098-44022003-01-016101320110.1103/PhysRevSTAB.6.013201Molecular desorption of stainless steel vacuum chambers irradiated with 4.2 MeV/u lead ionsE. MahnerJ. HansenJ.-M. LaurentN. MadsenIn preparation for the heavy ion program of the Large Hadron Collider at CERN, accumulation and cooling tests with lead ion beams have been performed in the Low Energy Antiproton Ring. These tests have revealed that due to the unexpected large outgassing of the vacuum system, the dynamic pressure of the ring could not be maintained low enough to reach the required beam intensities. To determine the actions necessary to lower the dynamic pressure rise, an experimental program has been initiated for measuring the molecular desorption yields of stainless steel vacuum chambers by the impact of 4.2 MeV/u lead ions with the charge states +27 and +53. The test chambers were exposed either at grazing or at perpendicular incidence. Different surface treatments (glow discharges, nonevaporable getter coating) are reported in terms of the molecular desorption yields for H_{2}, CH_{4}, CO, Ar, and CO_{2}. Unexpected large values of molecular yields per incident ion up to 2×10^{4} molecules/ion have been observed. The reduction of the ion-induced desorption yield due to continuous bombardment with lead ions (beam cleaning) has been investigated for five different stainless steel vacuum chambers. The implications of these results for the vacuum system of the future Low Energy Ion Ring and possible remedies to reduce the vacuum degradation are discussed.http://doi.org/10.1103/PhysRevSTAB.6.013201 |
| spellingShingle | E. Mahner J. Hansen J.-M. Laurent N. Madsen Molecular desorption of stainless steel vacuum chambers irradiated with 4.2 MeV/u lead ions Physical Review Special Topics. Accelerators and Beams |
| title | Molecular desorption of stainless steel vacuum chambers irradiated with 4.2 MeV/u lead ions |
| title_full | Molecular desorption of stainless steel vacuum chambers irradiated with 4.2 MeV/u lead ions |
| title_fullStr | Molecular desorption of stainless steel vacuum chambers irradiated with 4.2 MeV/u lead ions |
| title_full_unstemmed | Molecular desorption of stainless steel vacuum chambers irradiated with 4.2 MeV/u lead ions |
| title_short | Molecular desorption of stainless steel vacuum chambers irradiated with 4.2 MeV/u lead ions |
| title_sort | molecular desorption of stainless steel vacuum chambers irradiated with 4 2 mev u lead ions |
| url | http://doi.org/10.1103/PhysRevSTAB.6.013201 |
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