Lund University was founded in 1666 and is repeatedly ranked among the world’s top 100 universities. The University has 40 000 students and 7 400 staff based in Lund, Helsingborg and Malmö. We are united in our efforts to understand, explain and improve our world and the human condition.

MAX IV is a national large-scale research laboratory providing scientists from Sweden and the rest of the world with instruments for research in areas such as materials science, structural biology, chemistry and nanotechnology. Fully developed it will receive more than 2 000 scientists annually. 200 people are currently employed at the MAX IV Laboratory.

Title: Theoretical analysis of the residual perturbations on the stored beam produced by a multipole injection kicker.

Description

The MAX IV 3 GeV electron storage ring has been recently equipped with a Multipole Injection Kicker (MIK). This device allows the electron beam from the linear accelerator to be transferred, captured and accumulated in the storage ring while only minimally disturbing the already stored beam.  Minimizing the perturbations on the stored beam during the injection process is in fact a critical issue in modern machines in which injection is done rather often (every few minutes) in what is called the “top-up operation mode”.

By replenishing  the ring with electrons rather often one keeps the stored beam current nearly constant, which leads to a nearly constant heat load on accelerator and beamline components in turn resulting in improved stability of position and angle of the synchrotron light emitted by the electron beam. In most third generation storage ring sources, the injection makes use of three to four fast pulsed magnets (called kickers), which deflect the stored beam towards the injection septum and bring the injected beam into the rings acceptance.

Ideally, this scheme should allow the perturbations to the stored beam to be localized in both time and in space. However, in practice, it is extremely difficult to perfectly match all three or four kickers to produce a perfectly closed “bump” of the stored beam orbit, which leads to undesired residual oscillations of the stored beam that last for many hundreds of turns. The multipole injection kicker scheme implemented at MAX IV uses a different approach – instead of three or four kickers, only one kicker is used with a special spatial magnetic field profile which allows the injected beam to be kicked in while (ideally) not perturbing the stored beam at all. Again, real life tolerances render the scheme not absolutely perfect, but the experimental results obtained so far at MAX IV indicate that the MIK can generate perturbations that are significantly smaller than those typically obtained with a conventional four-kicker injection scheme.

In this project, the student will analyze theoretically the impact of the MIK pulsed fields on the stored beam through analytical calculations and numerical simulations. The aim is to determine a single figure of merit for the perturbations produced by the MIK that takes into account the fact the not all circulating bunches experience the same perturbation and that the vast majority of experiments at the storage ring beamlines actually only detect the time-average effect during a large number of turns. 

This summer project will consist in:

o   Introduction to accelerators and to the MAX IV 3 GeV ring, through review of the relevant literature.
o   Review of injection process and methods.
o   Development of analytical calculations based on linear approximation to the accelerator optics. Definition of an average “figure-of-merit” for the MIK perturbation.
o   Study of the impact of lattice non-linearities through simulations
o   Report writing

Time period: Mid June until mid August.

Type of employment Visstidsanställning kortare än 3 månader
Contract type Full time
Employment expires 2018-08-15
Number of positions 1
Working hours 100 %
City Lund
County Skåne län
Country Sweden
Reference number PA2018/882
Contact
  • Åke Andersson, +46462220414
Union representative
  • OFR/S:Fackförbundet ST:s kansli, 046-222 93 62, st@st.lu.se
  • SACO:Saco-s-rådet vid Lunds , 046-222 93 64, kansli@saco-s.lu.se
Published 26.Mar.2018
Last application date 17.Apr.2018 11:59 PM CET

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