Feasibility Study of Multi Turn ERL Based Synchrotron Light Facility

Energy Recovery Linacs ERL have been discussed as drivers for synchrotron radiation facilities in X ray region for over a decade. The first proposal for a multi turn ERL as a next generation synchrotron light facility was in 1997. Since then great advances in ERL technology and high brightness electron source development were achieved, ERL based high power free electron infrared laser at JLab and the demonstration of multi turn energy recovery at BINP. The feasibility of an X ray ERL based light source seems more and more realistic. An overview of the design of a multi turn ERL under development at Helmholtz Zentrum Berlin FSF Femto Science Factory is given in this pape

Analysis of Injection and Recovery Schemes for a Multi Turn ERL Based Light Source

A multi turn energy recovery linac based light source is under discussion. Using the superconducting Linac technology, the Femto Science Factory FSF will provide its users with ultra bright photon beams of angstrom wavelength. The FSF is intended to be a multi user facility and offer a variety of operation modes. The driver of the facility is a 6 GeV multiturn energy recovery linac with a split linac. In this talk we discuss designs of the optic in the linac and compare different schemes of beam acceleration a direct injection scheme with acceleration in a 6 GeV linac, a two stage injection with acceleration in a 6 GeV linac, and a multi turn 3 turn scheme with a two stage injection and two main 1 GeV linacs. Construction costs and beam break up instability were the key points for compariso

Multi turn ERL based light source Analysis of insection an recovery schemes.

The optics simulation group at HZB is designing a multi turn energy recovery linac based light source. Using the superconducting Linac technology, the Femto Science Factory FSF [1] will provide its users with ultra bright photon beams of angstrom wavelength. The FSF is intended to be a multi user facility and offer a variety of operation modes. The driver of the facility is a 6 GeV multiturn energy recovery linac with split linacs. In this paper we compare different schemes of beam acceleration a direct injection scheme with acceleration in a 6 GeV linac, a two stage injection with acceleration in a 6 GeV linac, and a multi turn 3 turn scheme with a two stage injection with two main 1 GeV linacs as proposed for FSF. The key characteristic of comparison is the beam breakup BBU instability threshold curren

Feasibility study of an ERL based GEV Scale multi turn ligth source

A new generation of particle accelerators based on an Energy Recovery Linac ERL is a promising tool for a number of new applications. These include high brilliance light sources in a wide range of photon energies, electron cooling of ion beam and ERL based electron hadron colliders. Helmholtz Zentrum Berlin started a feasibility study of GeV scale multi turn ERL based light source LS . This LS will work in diffraction limited regime in X rays and with a short length of a light pulse in femtosecond region. The average and peak brightness will be at least an order of magnitude higher than synchrotronbased LS. In this work an overview of the future multiturn light source is given. Estimations of the Beam Break Up instability are presente

Results from Beam Commissioning of an SRF Plug Gun Cavity Photoinjector

Superconducting rf photo electron injectors SRF photoinjectors hold the promise to deliver high brightness, high average current electron beams for future light sources or other applications demanding continuous wave operation of an electron injector. This paper discusses results from beam commissioning of a hybrid SRF photoinjector based on a Pb coated plug and a Nb rf gun cavity for beam energies up to 2.5MeV at Helmholtz Zentrum Berlin HZB . Emittance measurements and transverse phase space characterization with solenoid scan and slitmask methods will be presente

Status of the Novosibirsk terahertz FEL

The first stage of Novosibirsk high-power free-electron laser (FEL) was commissioned in 2003. It is based on a normal conducting CW energy recovery linac. Now the FEL provides electromagnetic radiation in the wavelength range of 120…180 micrometers. An average power is 400 W. The minimum measured line width is 0.3%, which is close to the Fourier-transform limit. A user-beamline assembly is in progress, parts of the full-scale machine are manufactured. The latter will operate in the near IR region and provide higher average powerВ 2003 году в Новосибирске заработала первая очередь мощного лазера на свободных электронах (ЛСЭ). Машина построена на базе линака-рекуператора непрерывного действия. В настоящее время ЛСЭ работает в диапазоне длин волн 120…180 мкм, его средняя мощность достигает 400 Вт. Минимальная измеренная ши- рина полосы излучения составляет 0.3%, что близко к теоретическому минимуму. В настоящее время монтируются каналы разводки излучения для пользователей, части полномасштабной машины запущены в производство. Полномасштабная машина будет работать в ближнем ИК-диапазоне и обладать большей мощностью.В 2003 році в Новосибірську заробила перша черга потужного лазера на вільних електронах (ЛВЕ). Машина побудована на базі лінака-рекуператора безперервної дії. Зараз ЛВЕ працює в діапазоні довжин хвиль 120...180 мкм, його середня потужність досягає 400 Вт. Мінімальна виміряна ширина смуги випромінювання становить 0.3%, що близько до теоретичного мінімуму. Зараз монтуються канали розведення випромінювання для користувачів, частини повномасштабної машини запущені у виробництво. Повномасштабна машина буде працювати в ближньому ІЧ-діапазоні і мати більшу потужність

Experimental study of negative photoconductivity in n-PbTe(Ga) epitaxial films

We report on low-temperature photoconductivity (PC) in n-PbTe(Ga) epitaxial films prepared by the hot-wall technique on -BaF_2 substrates. Variation of the substrate temperature allowed us to change the resistivity of the films from 10^8 down to 10_{-2} Ohm x cm at 4.2 K. The resistivity reduction is associated with a slight excess of Ga concentration, disturbing the Fermi level pinning within the energy gap of n-PbTe(Ga). PC has been measured under continuous and pulse illumination in the temperature range 4.2-300 K. For films of low resistivity, the photoresponse is composed of negative and positive parts. Recombination processes for both effects are characterized by nonexponential kinetics depending on the illumination pulse duration and intensity. Analysis of the PC transient proves that the negative photoconductivity cannot be explained in terms of nonequilibrium charge carriers spatial separation of due to band modulation. Experimental results are interpreted assuming the mixed valence of Ga in lead telluride and the formation of centers with a negative correlation energy. Specifics of the PC process is determined by the energy levels attributed to donor Ga III, acceptor Ga I, and neutral Ga II states with respect to the crystal surrounding. The energy level corresponding to the metastable state Ga II is supposed to occur above the conduction band bottom, providing fast recombination rates for the negative PC. The superposition of negative and positive PC is considered to be dependent on the ratio of the densities of states corresponding to the donor and acceptor impurity centers.Comment: 7 pages, 4 figure

First experimental results obtained using the highpower free electron laser at the siberian center for photochemical research

The first lasing near the wavelength of 140 µm was achieved in April 2003 using a high-power free electron laser (FEL) constructed at the Siberian Center for Photochemical Research. In this paper we briefly describe the design of the FEL driven by an accelerator–recuperator. Characteristics of the electron beam and terahertz laser radiation, obtained in the first experiments, are also presented in the paper.У Сибірському центрі фотохімічних досліджень навесні 2003 року отримана генерація випромінювання з довжиною хвилі 140 мкм на потужному лазері на вільних електронах (ЛВЕ). У роботі коротко описана конструкція ЛВЕ на базі прискорювача рекуператора і представлені результати вимірювання деяких параметрів електронного пучка і терагерцового випромінювання.В Сибирском центре фотохимических исследований весной 2003 года получена генерация излучения с длиной волны 140 мкм на мощном лазере на свободных электронах (ЛСЭ). В работе кратко описана конструкция ЛСЭ на базе ускорителя рекуператора и представлены результаты измерения некоторых параметров электронного пучка и терагерцового излучения

Linac optics design for multi turn ERL ligth source

The optics simulation group at HZB is designing a multi turn energy recovery linac based light source. Using the superconducting Linac technology, the Femto Science Factory FSF will provide its users with ultrabright photon beams of angstrom wavelength at 6 GeV. The FSF is intended to be a multi user facility and offer a variety of operation modes. In this paper a design of transverse optic of the beam motion in the Linacs is presented. An important point in the optics design was minimization of the beta functions in the linac at all beam passes to suppress beam break up BBU instabilit

Modeling of the beam break up instability in Berlin energy recovery Linac project

Helmholtz Zentrum Berlin officially started Jan. 2011 the design and construction of the Berlin Energy Recovery Linac Project BERLinPro. The initial goal of this compact ERL is to develop the ERL accelerator physics and technology required to accelerate a highcurrent low emittance beam. The conversion efficiency of an FEL is about 1 therefore superconducting ERL based FEL machines look promising. One of the problems of superconducting ERL machines is the Beam Break Up BBU instability which limits the current. In this work the threshold current of the BBU instability was calculated for the BERLinPro. The comparison of two 100 MeV linacs based on different type of superconducting cavities is made. Different methods of BBU suppression are investigated e.g. the influence of solenoid, pseudo reflector and quadruple triplets in the linac structure on the BBU threshol