Scientific Highlights from the Department
Large Research Facilities (GFA)
The emittance is a fundamental parameter of particle distributions accounting for the average spread of the particles’ positions and momenta. We have generated and characterized intense ultralow-emittance electron beams, setting new standards for electron linear accelerators. The measurements have been carried out at the SwissFEL accelerator of PSI. SwissFEL is one of the few X-ray free-electron lasers (FELs) worldwide, which are cutting-edge research instruments to investigate matter with resolutions at the level of atomic processes.
The IEEE Nuclear Plasma Science Society has recently awarded Dr. Paolo Craievich, leader of the group «RF-system 2» in GFA, with the Particle Accelerator Science Technology award for his exceptional contributions to accelerator science and technology. https://www.frib.msu.edu/events/2019/napac19/awards.html
We have produced ultra-short X-ray FEL pulses at SwissFEL by strongly compressing low-charge electron beams. Single-shot spectral measurements with only a single mode (see the figure below) indicate a pulse duration well below one femtosecond (detailed analysis on the exact pulse duration is ongoing).
X-band (12 GHz) radio-frequency (RF) accelerating structures are under consideration for future free electron lasers, medical linacs and linear colliders. Two such structures, built by PSI in the framework of a CERN/PSI collaboration, are currently being tested at high power at CERN.
A team of GFA and CPT physicists has worked out a novel achromatic beam optics concept for a proton therapy gantry. The article on the concept in the journal Zeitschrift für Medizinische Physik has been awarded a prize for the best publication in 2016. The jury states: „The paper of Alexander Gerbershagen et al. entitled „A novel beam optics concept in a particle therapy gantry utilizing the advantages of superconducting magnets” describes a new concept of a first order design of the beam optics of a superconducting proton therapy gantry beam. The jury was impressed by the well-structured experimental work with clear improvement of large momentum acceptance in the gantry which opens the possibility of implementation new and faster dose application techniques in proton therapy.”
Radio-frequency structures at X-band frequencies (~ 12 GHZ) are being considered for applications in compact Free Electron Lasers, medical linacs, a future linear collider (CLIC project) and as a diagnostic for measuring ultra-short (femtosecond) electron pulses in FELs. A first prototype of such a structure has been built at PSI employing the realization procedures that have been developed for the C-Band (6 GHz) structures of the SwissFEL linac.
On Thursday 08/09/2016, the first C-band module boosted an electron beam from 150MeV to 390 MeV. This is the first beam acceleration test of a C-band module in PSI and is an important milestone for the project, since the main accelerator consists of 26 C-band modules of the same kind.
The 21st conference in this series takes place from September 12 to 16, 2016 at the Federal Institute of Technology in Zürich. The cyclotron is a simple and efficient particle accelerator and its invention for the purpose of performing fundamental research dates back to 1929. Ernest Lawrence received the Nobel Prize for his idea in 1939. Today cyclotrons are used in a broad range of applications from large and complex facilities for basic research to highly optimized and cost effective solutions for industrial and medical applications. The series of cyclotron conferences provides a forum for the world leading experts to meet and to discuss technological and physics advancements in the field.
On August, 24th 2016, the electron gun accelerated the first photo-electrons in SwissFEL up to the energy of 7 MeV, initiating the beam commissioning phase of the new SwissFEL facility. After several days of RF conditioning, the gun reached the nominal acceleration gradient of 100MV/m at an input power of 17MW with a pulse-width of 1 micro second at an operating frequency of at 2998.8 MHz.