اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدProgress with the Upgrade of the SPS for the HL-LHC Era
93
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
The demanding beam performance requirements of the High Luminosity (HL-) LHC project translate into a set of requirements and upgrade paths for the LHC injector complex. In this paper the performance requirements for the SPS and the known limitations are reviewed in the light of the 2012 operational experience. The various SPS upgrades in progress and still under consideration are described, in addition to the machine studies and simulations performed in 2012. The expected machine performance reach is estimated on the basis of the present knowledge, and the remaining decisions that still need to be made concerning upgrade options are detailed.
قيم البحث
اقرأ أيضاً
Crab crossing is essential for high-luminosity colliders. The High Luminosity Large Hadron Collider (HL-LHC) will equip one of its Interaction Points (IP1) with Double-Quarter Wave (DQW) crab cavities. A DQW cavity is a new generation of deflecting R
F cavities that stands out for its compactness and broad frequency separation between fundamental and first high-order modes. The deflecting kick is provided by its fundamental mode. Each HL-LHC DQW cavity shall provide a nominal deflecting voltage of 3.4 MV, although up to 5.0 MV may be required. A Proof-of-Principle (PoP) DQW cavity was limited by quench at 4.6 MV. This paper describes a new, highly optimized cavity, designated DQW SPS-series, which satisfies dimensional, cryogenic, manufacturing and impedance requirements for beam tests at SPS and operation in LHC. Two prototypes of this DQW SPS-series were fabricated by US industry and cold tested after following conventional SRF surface treatment. Both units outperformed the PoP cavity, reaching a deflecting voltage of 5.3-5.9 MV. This voltage - the highest reached by a DQW cavity - is well beyond the nominal voltage of 3.4 MV and may even operate at the ultimate voltage of 5.0MVwith sufficient margin. This paper covers fabrication, surface preparation and cryogenic RF test results and implications.
The Mu2e experiment at Fermilab is being designed to study the coherent neutrino-less conversion of a negative muon into an electron in the field of a nucleus. This process has an extremely low probability in the Standard Model and its observation wo
uld provide unambiguous evidence for BSM physics. The Mu2e design aims to reach a single-event-sensitivity of about $2.5 times 10^{17}$ and will probe effective new physics mass scales in the 103-104 TeV range, well beyond the reach of the LHC. This work examines the maximum beam power that can be tolerated for beam energies in the 0.5-8 GeV range exploring variations in the geometry in the region of the production target using the MARS15 code. This has implications for how the sensitivity might be further improved with a second generation experiment using an upgraded proton beam from the PIP-II project, which will be capable of providing MW beams to Fermilab experiments later in the next decade.
The LHCb Upgrade II will fully exploit the flavour-physics opportunities of the HL-LHC, and study additional physics topics that take advantage of the forward acceptance of the LHCb spectrometer. The LHCb Upgrade I will begin operation in 2020. Conso
lidation will occur, and modest enhancements of the Upgrade I detector will be installed, in Long Shutdown 3 of the LHC (2025) and these are discussed here. The main Upgrade II detector will be installed in long shutdown 4 of the LHC (2030) and will build on the strengths of the current LHCb experiment and the Upgrade I. It will operate at a luminosity up to $ 2 times 10^{34} rm cm^{-2}s^{-1}$, ten times that of the Upgrade I detector. New detector components will improve the intrinsic performance of the experiment in certain key areas. An Expression Of Interest proposing Upgrade II was submitted in February 2017. The physics case for the Upgrade II is presented here in more depth. $CP$-violating phases will be measured with precisions unattainable at any other envisaged facility. The experiment will probe $bto s ell^+ell^-$ and $bto d ell^+ell^-$ transitions in both muon and electron decays in modes not accessible at Upgrade I. Minimal flavour violation will be tested with a precision measurement of the ratio of $B(B^0tomu^+mu^-)/B(B_s^0to mu^+mu^-)$. Probing charm $CP$ violation at the $10^{-5}$ level may result in its long sought discovery. Major advances in hadron spectroscopy will be possible, which will be powerful probes of low energy QCD. Upgrade II potentially will have the highest sensitivity of all the LHC experiments on the Higgs to charm-quark couplings. Generically, the new physics mass scale probed, for fixed couplings, will almost double compared with the pre-HL-LHC era; this extended reach for flavour physics is similar to that which would be achieved by the HE-LHC proposal for the energy frontier.
Several indicators have pointed to the presence of an Electron Cloud (EC) in some of the CERN accelerators, when operating with closely spaced bunched beams. In particular, spurious signals on the pick ups used for beam detection, pressure rise and b
eam instabilities were observed at the Proton Synchrotron (PS) during the last stage of preparation of the beams for the Large Hadron Collider (LHC), as well as at the Super Proton Synchrotron (SPS). Since the LHC has started operation in 2009, typical electron cloud phenomena have appeared also in this machine, when running with trains of closely packed bunches (i.e. with spacings below 150ns). Beside the above mentioned indicators, other typical signatures were seen in this machine (due to its operation mode and/or more refined detection possibilities), like heat load in the cold dipoles, bunch dependent emittance growth and degraded lifetime in store and bunch-by-bunch stable phase shift to compensate for the energy loss due to the electron cloud. An overview of the electron cloud status in the different CERN machines (PS, SPS, LHC) will be presented in this paper, with a special emphasis on the dangers for future operation with more intense beams and the necessary countermeasures to mitigate or suppress the effect.
This paper describes a programme to study the computing model in CMS after the next long shutdown near the end of the decade.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
