We review the basic concepts of beam dynamics in ultra low emittance rings including single particle and collective effects. Some emphasis is given to correct implementation of the optics, with the relevant operational issues and diagnostics requirements.
Different approaches to infer magnet and optics parameters from beam-based measurements at the ESRF storage ring are reviewed. Main results and limits of the established techniques are examined. Possible improvements or alternatives are proposed and discussed in the light of first experimental results. A report on accuracy studies of linear optics measurements, based on both turn-by-turn and...
The 10kHz fast acquisition BPMs together with an AC excitation of the corrector magnets allow to speed up the beam based alignment process at ALBA. The former approach relies on software synchronization and tango device servers to execute a series of DC corrector magnets and quadrupoles settings designed to avoid the quadrupole hysteresis effects. The approach that we present here is simpler,...
In January 2018, a Topical Workshop on Emittance Measurements for Light Sources and FELs was held at ALBA. This talk will summarise the relevant part for 'rings' by marking current state of the art and pointing out opportunities for further development.
Designing a low emittance ring is generally achieved at the cost of a lower beam lifetime. To ensure a relatively constant current in the ring it is therefore compulsory to use a top-up refill scheme with frequent injections. Unfortunately injections are not completely transparent for users, the pulsed magnets (septa or kickers) induce some perturbation of the beam motion (closed orbit) and...
A dissector is an electron-optical device designed for measurement of periodic light pulses of subnanosecond and picosecond duration. LI-602 dissector developed at BINP is widely used for routine measurements of a longitudinal profile of electron and positron beams at BINP electron-positron colliders and other similar installations. LI-602 provides a temporal resolution of about 20 ps. A new...
While recent diffraction limited storage rings provide bunches with transverse dimensions smaller than the wavelength of the observed synchrotron radiation, this is still challenging in the longitudinal plane. The self interaction of a short electron bunch with its emitted coherent radiation can lead to the micro-bunching instability. Therefore, the bunch compression in storage rings is...
Already now BESSY II is operated with a complex fill pattern, in order to fulfill many different user-demands simultaneously. Thus, properties like current, bunch size and bunch length vary on a bunch-by-bunch level, which require dedicated diagnostics for the stable operation of the machine. With the advent of BESSY VSR, the variable bunch-length storage ring, bunch resolved diagnostics will...
In this contribution, we describe the advantages of the pilot tone compensation technique that we implemented in a new BPM prototype. Injecting a fixed reference tone upstream of cables allows for a continuous calibration of the system, compensating the different behaviour of every channel due to thermal drifts, variations of cable properties, mismatches and tolerances of components.
Another...
Abstract
Based on the demand of high energy photo source(HEPS), the goal of digital Beam position monitor(BPM) electronics is to develop a high precision beam control and measurement system, which can make the precise measurement of turn-by-turn (TBT) data, fast acquisition(FA) data, Slow acquisition (SA) data and closed orbit data (COD) data.
The hardware architecture of digital BPM includes...
Libera Brilliance+ is the third generation of BPM electronics which have been running in several light sources around the world. It's adaptive signal processing based on either frequency or time domain provided flexibility to measure both turn-by-turn and single bunch beam position. Furthermore, the long-term stabilization concept based on the crossbarswitch enabled it to achieve the stability...
There are proposals to utilize the energy recovery linac (ERL) as driver for the light sources with ultra-low emittance. The ERLs have co-propagating beams inside the same vacuum vessel. These beams can have different trajectories, which should be distinguished by beam position monitors (BPM). In this paper we present a concept of a BPM utilizing the phase information for calculation...
The design study of new button-type beam position monitor (BPM) is performed for a high accuracy bunch-by-bunch BPM system. Particularly it is mainly to compensate the influence of ringing signal which causes the misreading of the beam position of following bunches. The ringing is produced by the combined effect of an impedance mismatching inside the button and trapped TE-mode inside the...
NSLS-II in-house developed BPM systems provide better than 200nm resolution and sub-micron long-term position stability, combined with the high-temperature stability of the storage ring tunnel, electronic racks, sophisticated support structures and orbit feedback. The talk will start with brief introduction of the NSLS-II BPM button and electronics design and achieved performances. The talk...
The work on stability for MAX IV took speed around 2010 and has since been an important factor in calculations and designs for buildings, supports and the components of accelerators and beamlines. The stability work is now in a different phase, where observations of stability and instabilities emerges. This is the reason for establishing the MAX IV Stability Task Force in 2016. I will give a...
In this talk we review measurements obtained with a Hydrostatic Levelling System (HLS) at Diamond. Two versions have been installed, the first of which ran along the length of a single beamline, and the second followed the full circumference of the storage ring inside the tunnel. The construction of the Diamond facility, details of the HLS system, results from both systems and experience...
The APS upgrade entails a complete replacement of the APS storage ring with
a multi-bend achromat lattice, resulting in a reduction in natural
emittance by more than a factor of 50, nominally to 42 pm-rad. This will
reduce the horizontal beam size at insertion device source points to below
15 microns rms, and the vertical beam size to below 3 microns at 10%
coupling. An extensive R&D program...
SLS 2.0 is the upgrade Project of the Swiss Light Source (SLS) at the Paul Scherrer Institut in Villigen, Switzerland. The new 7-bend achromat lattice will reduce the natural emittance by a factor of ~40 providing higher brightness and coherent photons for the users.
This contribution shortly introduces the SLS 2.0 project and summarizes the first considerations about beam instrumentation and...
High Energy Synchrotron Photon Source（HEPS）is an ultra-low emittance light source, of which the energy is 6 GeV and the beam current is 200mA. There are many challenges in hardware design and fabrication. As to beam instrumentation, sub-micron level beam position measurement system, synchrotron light measurement system based x-ray and the feedback system including FOFB, TFB and LFB should be...
