Electron cloud observations and cures in RHIC DISCLAIMER ELECTRON CLOUD OBSERVATIONS AND CURES IN RHIC*

Abstract OBSERVATIONS Since 2081 M I C has experienced electron cloud effects, which have Iimited the beam intensity. These include dynamic pressure rises -including pressure instabilities, tune shifts: electrons, a reduction of the stability threshold for bunches crossing the transition energy, and possibly slow emittance growth. We summarize the main observations in operation and dedicated experiments, as well as countermeasures including baking, NEG coated warm beam pipes, solenoids, bunch patterns, anti-grazing rings, pre-pumped cold beam pipes, and scrubbing. This article is a condensed version of Ref. El]. Dynamic pressure rise from electron-impact desorption after an electron cloud has been formed was the first, and still is the most common electron cloud observation in RHI

Search for leptoquarks in Z0 decays

General rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Received 5 March 1991 We have searched for direct leptoquark production in Z ° decays from a scan of the Z ° resonance, in the energy range 88.2 ~< x/] ~< 94.2 GeV, using 5.2 pb-~ of data. We exclude the existence of scalar leptoquarks with masses less than 41 to 44 GeV, depending on the charge assignments, at the 95% confidence level