Beam-Breakup Instability Theory for Energy Recovery Linacs

Here we will derive the general theory of the beam-breakup instability in recirculating linear accelerators, in which the bunches do not have to be at the same RF phase during each recirculation turn. This is important for the description of energy recovery linacs (ERLs) where bunches are recirculated at a decelerating phase of the RF wave and for other recirculator arrangements where different RF phases are of an advantage. Furthermore it can be used for the analysis of phase errors of recirculated bunches. It is shown how the threshold current for a given linac can be computed and a remarkable agreement with tracking data is demonstrated. The general formulas are then analyzed for several analytically solvable cases, which show: (a) Why different higher order modes (HOM) in one cavity do not couple so that the most dangerous modes can be considered individually. (b) How different HOM frequencies have to be in order to consider them separately. (c) That no optics can cause the HOMs of two cavities to cancel. (d) How an optics can avoid the addition of the instabilities of two cavities. (e) How a HOM in a multiple-turn recirculator interferes with itself. Furthermore, a simple method to compute the orbit deviations produced by cavity misalignments has also been introduced. It is shown that the BBU instability always occurs before the orbit excursion becomes very large.Comment: 12 pages, 6 figure

Status of “ZELENOGRAD” storage ring

In 2000, after a long break, works on creation of a technological storage ring complex (TSC) have been renewed in ZELENOGRAD. TSC was developed at Budker INP of Siberian Branch of Russian Academy of Science. It consists of a linear accelerator on the electron energy up to 80 MeV, a small storage ring on the energy 450 MeV, a main storage ring on the energy 2 GeV and two electron transfer lines (TL-1 and TL-2). The Main Ring (MR) with energy of electrons 2 GeV is the dedicated synchrotron radiation source intended for the decision of problem of submicron technologies and realization of various researches in a range of wavelengths of 0.2…2000 Å. Linac was mounted and put into operation during 2000-2002. The circulating electron current was received in small storage ring in 2005. Currently, the assembling of TL-2 is being completed. The inspection of the main storage ring equipment made before is carried out. Besides, a modification of all control and power supply system MR is done and a modern electronic element base will be introduced. The status and the nearest planes concerning TSC main storage ring are described.У 2000 р. після довгої перерви відновилися роботи по створенню технологічного накопичувального комплексу - ТНК, у м. Зеленограді. ТНК був розроблений в ІЯФ СВ РАН. Він складається з лінійного прискорювача (ЛП) на енергію до 80 МеВ, малого накопичувача (МН) на енергію 450 МеВ, основного великого накопичувача (ВН) на енергію 2,2 ГеВ і двох каналів перепуску (ЕОК-1 й ЕОК-2). Накопичувач електронів з енергією електронів Е = 2,2 ГеВ є спеціалізованим джерелом СВ, призначеним для вирішення проблем субмікронних технологій, а також для проведення досліджень у проміжку довжин хвиль 0.2…2000 Å. Лінійний прискорювач був змонтований і запущений протягом 2000-2002 р. У 2005 р. був отриманий циркулюючий струм електронів у Малому накопичувачі. У цей час закінчується монтаж ЕОК-2. Проводиться ревізія устаткування ВН. Крім того, проводиться модернізація всіх систем керування і живлення і перехід на сучасну елементну базу. Описується статус ТНК і найближчі плани по монтажу і запуску ВН.В 2000 г. после долгого перерыва возобновились работы по созданию технологического накопительного комплекса – ТНК, в г. Зеленограде. ТНК был разработан в ИЯФ СО РАН. Он состоит из линейного ускорителя (ЛУ) на энергию до 80 МэВ, Малого накопителя (МН) на энергию 450 МэВ, основного большого накопителя (БН) на энергию 2.2 ГэВ и двух каналов перепуска (ЭОК-1 и ЭОК-2). Накопитель электронов с энергией электронов Е = 2.2 ГэВ является специализированным источником СИ, предназначенным для решения проблем субмикронных технологий, а также для проведения исследований в области длин волн 0.2…2000 ангстрем. Линейный ускоритель был смонтирован и запущен в течение 2000-2002 г. В 2005 г. был получен циркулирующий ток электронов в Малом накопителе. В настоящее время заканчивается монтаж ЭОК-2. Проводится ревизия оборудования БН. Кроме того, проводится модернизация всех систем управления и питания и переход на современную элементную базу. Описывается статус ТНК и ближайшие планы по монтажу и запуску БН

The Large Hadron-Electron Collider at the HL-LHC

The Large Hadron-Electron Collider (LHeC) is designed to move the field of deep inelastic scattering (DIS) to the energy and intensity frontier of particle physics. Exploiting energy-recovery technology, it collides a novel, intense electron beam with a proton or ion beam from the High-Luminosity Large Hadron Collider (HL-LHC). The accelerator and interaction region are designed for concurrent electron-proton and proton-proton operations. This report represents an update to the LHeC's conceptual design report (CDR), published in 2012. It comprises new results on the parton structure of the proton and heavier nuclei, QCD dynamics, and electroweak and top-quark physics. It is shown how the LHeC will open a new chapter of nuclear particle physics by extending the accessible kinematic range of lepton-nucleus scattering by several orders of magnitude. Due to its enhanced luminosity and large energy and the cleanliness of the final hadronic states, the LHeC has a strong Higgs physics programme and its own discovery potential for new physics. Building on the 2012 CDR, this report contains a detailed updated design for the energy-recovery electron linac (ERL), including a new lattice, magnet and superconducting radio-frequency technology, and further components. Challenges of energy recovery are described, and the lower-energy, high-current, three-turn ERL facility, PERLE at Orsay, is presented, which uses the LHeC characteristics serving as a development facility for the design and operation of the LHeC. An updated detector design is presented corresponding to the acceptance, resolution, and calibration goals that arise from the Higgs and parton-density-function physics programmes. This paper also presents novel results for the Future Circular Collider in electron-hadron (FCC-eh) mode, which utilises the same ERL technology to further extend the reach of DIS to even higher centre-of-mass energies.Peer reviewe

The Large Hadron–Electron Collider at the HL-LHC

The Large Hadron–Electron Collider (LHeC) is designed to move the field of deep inelastic scattering (DIS) to the energy and intensity frontier of particle physics. Exploiting energy-recovery technology, it collides a novel, intense electron beam with a proton or ion beam from the High-Luminosity Large Hadron Collider (HL-LHC). The accelerator and interaction region are designed for concurrent electron–proton and proton–proton operations. This report represents an update to the LHeC’s conceptual design report (CDR), published in 2012. It comprises new results on the parton structure of the proton and heavier nuclei, QCD dynamics, and electroweak and top-quark physics. It is shown how the LHeC will open a new chapter of nuclear particle physics by extending the accessible kinematic range of lepton–nucleus scattering by several orders of magnitude. Due to its enhanced luminosity and large energy and the cleanliness of the final hadronic states, the LHeC has a strong Higgs physics programme and its own discovery potential for new physics. Building on the 2012 CDR, this report contains a detailed updated design for the energy-recovery electron linac (ERL), including a new lattice, magnet and superconducting radio-frequency technology, and further components. Challenges of energy recovery are described, and the lower-energy, high-current, three-turn ERL facility, PERLE at Orsay, is presented, which uses the LHeC characteristics serving as a development facility for the design and operation of the LHeC. An updated detector design is presented corresponding to the acceptance, resolution, and calibration goals that arise from the Higgs and parton-density-function physics programmes. This paper also presents novel results for the Future Circular Collider in electron–hadron (FCC-eh) mode, which utilises the same ERL technology to further extend the reach of DIS to even higher centre-of-mass energies