IHEP Beijing, Beijing
China Spallation Neutron Source (CSNS) is a high power proton accelerator-based facility. Uncontrolled beam loss is a major concern in designing the high power proton accelerators to control the radio-activation level. For the Rapid Cycling Synchrotron (RCS) of the CSNS, the repetition frequency is too high for the longitudinal motion to be fully adiabatic. Significant beam loss happens during the RF capture and initial acceleration. To reduce the longitudinal beam loss, phase space painting is used in the RCS injection. This paper presents detailed simulation studies on the longitudinal motion in the RCS by using the ORBIT code, which include different beam chopping factors, momentum offsets, injection times and RF voltage patterns. With a trade-off between the longitudinal beam loss and transverse incoherent tune shift that will also result in beam losses, optimized longitudinal painting schemes are obtained.
LNLS, Campinas
UVX is a 1.37 GeV electron storage ring at the Brazilian Synchrotron Light Laboratory (LNLS). The ring is composed of a 6-fold symmetric double-bend achromat lattice with 4 sections reserved for insertion devices. The storage ring was commissioned in 1997 in a mode of operation with high (~12 m) vertical betatron functions in the insertion straights. However, the need for operation with reduced vertical aperture arose with the gradual installation of insertion devices over the years and is particularly important for operation with a 14 mm vertical aperture superconducting wiggler scheduled for installation in late 2009. To cope with this restricted aperture, a new mode with low (~0.8 m) vertical betatron function in all six long straights was deemed necessary and was implemented at the end of 2008. In this report we present the commissioning results of the low vertical beta mode and the advantages in operating in this mode with insertions.
LNLS, Campinas
We present an overview of a new synchrotron radiation source currently being designed at the Brazilian Synchrotron Light Laboratory (LNLS) in Campinas. The LNLS-1 light source, based on a 1.37 GeV storage ring, has been in routine operation since 1997. The LNLS-2 light source will consist of an injector system and a low emittance 2.5 GeV electron storage ring capable of delivering undulator radiation with average brightness in excess of 1020 photons/sec/0.1%/mm2/mrad2 in the few hundred eV to several tens of keV photon energy range. High flux radiation up to 100 keV will also be available with the use of superconduting wigglers. In this work, we present the basic design considerations and parameters for a proposed magnetic lattice for LNLS-2, with special attention to providing solutions for the realization of low emittance which are cost effective regarding both the construction investment as well as the operation of the facility. In particular, the possibility of the large scale use of permanent magnet technology for the storage ring lattice magnets is discussed.
LNLS, Campinas
The UVX electron storage ring at the Brazilian Synchrotron Light Laboratory (LNLS) was recently equipped with active current shunt circuits that allow for individual variation of the quadrupole magnet strengths. This allows us to apply the widely used technique of beam-based alignment (BBA) to calibrate the electrical center offset of the BPMs with respect to the magnetic center of the closest quadrupole. In this report we present the BBA experimental results and an analysis of the resolution of the method in the case of the LNLS UVX storage ring.
LNLS, Campinas
The synchrotron machine at the Brazilian Synchrotron Light Laboratory (LNLS) is a storage ring for 1.37 GeV electrons composed of six DBA cells whose lengths add up to around 93 meters of circumference. There are 18 horizontal and 24 vertical correctors available in the ring for correcting the orbit as measured at 24 BPMs. In the past, stored beams have been delivered which successfully fulfilled user’s stability and emittance demands. This has been accomplished by fine tuning the machine using mostly measured beam parameters. The ongoing commissioning of the a new undulator beamline, which is expected to become the most demanding one, puts pressure in the direction of improving existing models of the ring optics in order to envisage ways of improving beam quality. In this paper we discuss preliminary tests with LOCO* at the LNLS. We report on the impact of the calibration of the machine based on LOCO calculations through the analysis of standard experiments and optics parameters such as beta-beat reduction, improvement of life-time and so on.
*LOCO in the Beam Dynamics Newsletter, 44, ICFA, December 2007.
USTC/NSRL, Hefei, Anhui
IHEP Beijing, Beijing
TiN coating has been widely applied in surface treatments of particle accelerator vacuum chambers because of its characteristics such as good electrical conductivity, stability of performance, ability to block hydrogen permeation, low SEY, etc. With DC sputtering, TiN film has been coated on the inner face of a stainless steel pipe vacuum chamber, 86 mm in diameter and 2300 mm in length. The vacuum performances testing of the coated chamber has also been done, including thermal outgassing rate measurement, PSD measurement, and SEY measurement of samples. Compared with those of uncoated stainless steel chamber, the results show that coating TiN film is a very effective method of the treatment of particle accelerator vacuum chamber.
USTC/NSRL, Hefei, Anhui
Hefei Light Source is a second generation VUV light source, whose performance cannot meet the requirements of synchrotron radiation users at the present time. One year ago, the concept of the Hefei Advanced Light Source, whose main features are ultra low beam emittance and high brilliance in VUV and soft X-ray range, was brought forward. In the preliminary design study, a medium scale storage ring and multi bend achromat focusing structure were adopted to achieve beam emittance lower than 0.2 nm.rad. Linear and nonlinear parameter optimizations were performed to obtain large on-momentum and off-momentum dynamic aperture. The design status will be introduced briefly in the presentation.
USTC/NSRL, Hefei, Anhui
Funding: supported by National Natural Science Foundation of China (10705027)
Hefei Advanced Light Source(HALS) is a super low emittance storage ring and has a very poor beam life time. In order to run the ring stablely, Top-up injection will be necessary. Injection system will greatly affect the quality of beam. This article first give a physics design of injecting system. Then the injecting system is tracked under different errors. The responses of storage beam and injecting beam is given in the article.
USTC/NSRL, Hefei, Anhui
A bunch-by-bunch analogue transverse feedback system at the Hefei Light Source (HLS) is to cure the resistive wall instability and the transverse coupled bunch instabilities. The kicker of the feedback system has four 21-cm-long electrodes of stripline type mounted in a skew 45°. Calculation and Simulation of the transverse kicker are shown.
USTC/NSRL, Hefei, Anhui
IHEP Beiing, Beijing
SINAP, Shanghai
IHEP Beijing, Beijing
SSRF, Shanghai
In this paper, we introduce the BxB transverse feedback systems at Hefei Light Source (HLS), which employ an analog system and a digital system. The construction and commissioning for two feedback systems, as well as the instability analysis of beam and the experiment result of the feedback system in HLS are also presented in this paper.
USTC/NSRL, Hefei, Anhui
As low injection energy and multi-turn injection at HLS, the task of diagnosing and curing coupled-bunch instabilities becomes ever harder. The transverse analog feedback system has been redeveloped to improve effect, recently. In this paper, the new improved designs are described and new system's commissioning results are discussed. The transverse coupled bunch instability at 200MeV injection status is also experimentally studied.
USTC/NSRL, Hefei, Anhui
In order to meet the increasing requirements of synchrotron radiation users, a new plan of VUV and soft X-ray light source, named Hefei Advanced Light Source (HALS), is brought forward by National Synchrotron Radiation Laboratory (NSRL). This 1.5GeV storage ring with ultra low emittance 0.2nmrad consists of 18 combined FBA cells and the circumference is 388m. Strong enough quadrupoles and sextupoles must be needed for getting such low emittance lattice, which will lead beam close orbit distortions’ (COD) sensitivity to the field and alignment errors in magnets. Estimation of the COD from various error sources is investigated. Using orbit response matrix and singular value decomposition method, the distribution of beam position monitors and the location of correctors are reported in the paper. Simulation proves that COD can be corrected down to 60 microns level. In the same time the corrector strengths are weaker enough in the correction scheme.