Beam threading for the MAX IV accelerators

Abstract

Large particle accelerators are difficult to setup. One of the first problems that can be encountered, before production configuration is found, is the beam not passing through the accelerator. The process of guiding the beam through the accelerator is called beam threading. Depending on the accelerator complexity it can take days before the beam passes for the first time.

Currently the beam threading at MAX IV is performed manually. In addition to the long average time spent, the procedure of manual beam threading is labor-intensive and tiresome. An automated solution offers the advantage of greatly speeding up this process saving both time, effort and resources.

For this project an automated beam threader was developed for the 3 GeV and 1.5 GeV storage rings at MAX IV. The algorithm optimizes the available corrector magnets and uses beam position monitors or an oscilloscope to get an instant information on its progress. This way only minor effort by control room personnel is needed.

The typically low signal to noise ratio in the used diagnostics made noise filtering necessary. A successful decrease of the noise levels was achieved with spectral filters. Robust counting of the number of completed turns by the beam during threading from the filtered signal is developed. It is used by the automated beam threader as a metric of progress.

The automated beam threader successfully functions on the MAX IV storage rings and in simulation. It performs significantly faster than the manual threading procedure and in early attempt it outperformed the fastest manual threading for half of the time of the latter.

Popular Abstract

A new software can lead to faster guiding of electrons just like a thread is guided through the eye of a needle. With it, time can be saved and researchers can start their work earlier and bring new discoveries sooner.

The synchrotron is a large ring of electromagnets. Charged particles fly inside a vacuum tube in the ring with a speed close to the speed of light. In particle physics, where the fundamental rules of the universe are studied, the synchrotrons accelerate the particles to make them hit each other at very high speeds. An example is the Large Hadron Collider in CERN. The synchrotrons are also used to store electrons for light production.

Fast electrons shine a special light when they fly through specific magnetic devices. This light can be used like a flashlight for very small objects like molecules and atoms. With it researchers can study body tissues to understand how lung diseases are growing. They can also look at protein molecules to see their structure and shape. The chemical elements of a substance can be discovered and this is one way to detect pollution in soil samples. For few examples of the benefits, experiments like these help to create new cures or quicken the development of materials for sustainable future.

Special facilities are build with the goal to get brighter light from the fast electrons. The MAX IV Laboratory with its synchrotrons here in Lund is an example for such facility. With its innovative design it is referred as a next generation light source.

Putting electrons inside a synchrotron is tricky and sometimes does not work at all. When the electrons do not follow the their intended path, they hit the vacuum tube and are lost. In such case, they need to be threaded through the ring of electromagnets like a thread through many needles. A trained operator has to manually make corrections until the electrons can stay in the synchrotron after they are send to it. It is a tedious task that can take many days.

Running a large synchrotron is expensive and requires a lot of resources, so every hour counts. This is why the automated threading is beneficial. A faster start up will also allow research to begin sooner. The automated threading in MAX IV Laboratory can guide the electrons through the synchrotrons in less than an hour. In the laboratory this is faster than any threading done before.

• author: Georgiev, Georgi
• supervisor: Magnus Sjöström; Sverker Werin
• organization: Department of Physics; MAX IV Laboratory
• course: MAXM30 20181
• year: 2018
• type: H2 - Master's Degree (Two Years)
• subject: Physics and Astronomy; Technology and Engineering
• keywords: synchrotron, synchrotrons, electron beams, threading, beam threading, accelerator, accelerators, automated, storage rings, storage ring, electron accelerators, noise filtering
• language: English
• id: 8950164
• date added to LUP: 2018-06-19 09:26:05
• date last changed: 2018-06-19 09:26:05