Sverker Werin

The MAX II synchrotron radiation storage ring

A 1.5 GeV third generation storage ring optimised for the VUV and soft X-ray spectral region is currently being built at MAX-lab. The magnet lattice, ring architecture and production choices are optimised to fit within rather tight boundary conditions without sacrificing performance. In this paper, the magnet lattice, light characteristics, injection and technical solutions for the ring are presented.

Submicrometer-resolution photoelectron-spectroscopy at MAX Lab

The design of a photoemission microprobe beamline at the MAX laboratory is presented. The beamline will utilize the radiation from a 26 period undulator on the 550‐MeV MAX storage ring. The beamline will be capable of providing about 1010 photons/s of monochromatized radiation (bandwidth better than 0.25 eV) in the energy range of 20 to 150 eV focused into a submicrometer focal spot. It will be used for scanning photoemission experiments with a lateral resolution better than 1 μm. The optical system is comprised of a plane‐grating monochromator with a Kirkpatrick–Baez objective and a specially designed ellipsoidal focusing mirror.

Metrology of high-order harmonics for free-electron laser seeding

We examine the characteristics of high-order harmonics generated with 800 nm, 25 mJ, 160 fs laser pulses in an Ar gas cell with the objective of seeding a free electron laser. We measure the energy per pulse and per harmonic, the energy jitter, the divergence and the position stability of the harmonic beam. We perform ab initio numerical simulations based on integration of the time-dependent Schrodinger equation and of the wave equation within the slowly varying envelope approximation. The results reproduce the experimental measurements to better than a factor of two. The interaction of a frequency comb of harmonic fields with an electron bunch in an undulator is examined with a simple model consisting of calculating the energy modulation owing to the seed-electron interaction. The model indicates that the undulator acts as a spectral filter selecting a given harmonic. (Less)

The design of a 3 GHz thermionic RF-gun and energy filter for MAX-lab

A new pre-injector has been designed for the MAX-laboratory. It consists of an RF-gun and a magnetic energy filter. The newly designed RF-gun geometry will be operated at 3 GHz in the thermionic mode using a BaO cathode. The pre-injector will provide a 2.3 MeV electron beam in 3 ps micro pulses to a new injector system currently under construction

Experiences with the narrow gap undulator at MAX-lab

An undulator with short poles (period 24 mm) and extremely narrow gap (magnet gap 7.7 mm) using a squeezable vacuum chamber has been installed and is in operation at the MAX-lab 550 MeV storage ring. The device operates with a vacuum chamber aperture down to 6.2 mm. The behaviour of the storage ring concerning lifetime, emittance, tune shift and closed orbit is well described by conventional models. We present here the design of the device, the influence on the storage ring and the spectral characteristics, as well as comparison with expected theoretical results and an overview of the activities at the beam line.

A VUV undulator for MAX

Abstract An undulator operating at radiation wavelengths between 250 and 2000 A has been constructed at the Technical Research Centre of Finland and recently installed at the MAX storage ring in Lund. The undulator utilizes ferrite permanent magnets in the hybrid configuration. The magnetic and mechanical design, calculated performance and influence on the electron beam of the undulator are discussed.

The MAX IV Facility

The MAX IV facility is a planned successor of the existing MAX facility. The planned facility is described below. It consists of two new synchrotron storage rings operated at different electron energies to cover a broad spectral region and one linac injector. The linac injector is also meant to be operated as a FEL electron source. The two rings have similar low emittance lattices and are placed on top of each other to save space. A third UV light source, MAX III, is planned to be transferred to the new facility.

The max-IV design: Pushing the envelope

The proposed MAX IV facility is meant as a successor to the existing MAX-lab. The accelerator part will consist of three storage rings, two new ones operated at 3 and 1.5 GeV respectively and the existing 700 MeV MAX III ring. The two new rings have identical lattices and are placed on top of each other. Both these rings have a very small emittance, 0.86 and 0.4 nm rad respectively, and offer synchrotron radiation of very high mean brilliance. As an injector, a 3 GeV linear accelerator is planned. The design philosophy and the special technical solutions called for are presented in this paper.

First results in coherent harmonic generation using the undulator at the MAX-lab electron storage ring

An experiment in coherent harmonic generation has been performed at the MAX-lab electron storage ring in Lund. Coherent photons were produced in the third harmonic of a Nd:YAG laser focused on the electron beam in a permanent magnet undulator. The number of coherent photons, the linewidth, the current dependence and other parameters have been measured.

A cascaded optical klystron on an energy recovery linac – race track microtron

We are currently investigating a device capable of generating continuous, coherent radiation down in the Angstrom region in sub-ps pulses in a relatively compact set-up. By placing a cascaded optical klystron (OK) in the return path of a 3 GeV Race Track Microtron operating in Energy Recovery mode Harmonic Generation can be performed in several stages in parallel. A four stage OK can generate Angstrom radiation from a 266 nm seed. The demands on the electron optics are severe, but the requirements on the electron beam are not extreme. The layout of a possible facility is presented and the basic concepts are discussed below