Endstation Description
The composite velocity imaging spectrometer (CpVMI) is one of two novel instruments at the Shanghai soft x-ray free electron laser (SXFEL) for AMO science. The CpVMI consists of an ultrasonic molecular beam generation device, an electron velocity imaging system, a three-dimensional ion momentum imaging system and a vacuum system. The molecular beam or cluster beam generated by the ultrasonic molecular beam device enters the reaction chamber and interacts with the x-ray free electron laser or optical laser pulses, and then the produced electrons and ions fly towards the electron and ion imaging systems to obtain their momentum and energy information. The pump-probe scheme can be supported with in-coupling of x-ray with the external optical laser. The scientific objectives are to reveal the quantum characteristics such as strong field nonlinear phenomena, ultrafast dynamics of photoexcited systems, nanoplasma formation and evolution, and photoelectron diffraction and so on. Compared with the existing advanced spectrometers in the world, a major feature of the CpVMI is that the dynamical measurement range of electronic kinetic energy upgrades from 100 eV up to 1000 eV with a higher energy resolution, which provides a powerful observation capability for the related physical and chemical processes.
Specifications
Parameters | HGHG mode | SASE mode |
Photon Energy Range | 50-600 eV | 100-1000 eV |
Photon Energy Resolution | ~0.01% | ~0.2% |
Focus spot size (FWHM) | <5x5 μm2 (KB) | <3x3 μm2 (KB) |
Pulse Energy | ~26 μJ@400 eV | ~140 μJ@620 eV |
Photon Pulse Duration | ~50 fs | ~120 fs |
Repetition Rate | 1-50 Hz | 1-50 Hz |
Polarization | Circular, Horizontal | Horizontal |
Optical Laser | Normally 800 nm, and can be required with varying power, repetition rate, and pulse duration | |
Primary Techniques | High energy resolution velocity imaging microscope Optical pump / X-ray Probe | |
Collected Electron Energy | <1120 eV with an energy resolution of ~1.2% | |
Collected Ion Energy | <20 eV with an energy resolution of ~3% | |
Samples | Gaseous phase atoms and small molecules, atomic clusters; Diffusive molecular beam option | |
AMO International Advisory Panel
Prof. Dajun Ding (Jilin Univ., China)
Prof. Kiyoshi Ueda (Tohoku Univ., Japan)
Prof. James Cryan (PULSE Institute, SLAC National Accelerator Laboratory, USA)
Prof. Jon Marangos (Imperial College London, UK)
Prof. Christoph Bostedt (Paul Scherrer Institute (PSI); Ecole Polytechnique Federale de Lausanne, Switzerland)
Prof. Hans Jakob Wörner (ETH Zürich, Switzerland)
Prof. Michael Meyer (EuXFEL, Germany)
Prof. Till Jahnke (EuXFEL; Goethe-Universität Frankfurt, Germany)
Prof. Sang-kil Son (The Center for Free-Electron Laser Science (CFEL), Germany)
Prof. Carlo Callegari (FERMI, Italy)
Prof. Jan-Erik Rubensson (Uppsala University, Sweden)
Prof. Maria-Novella Piancastelli (Sorbonne Université, France; Uppsala University, Sweden)
Prof. Philippe Wernet (Uppsala University, Sweden)
Prof. Fernando Martín García (Universidad Autónoma de Madrid, Spain)
Prof. Ken-ichi Ishikawa (Univ. Tokyo, Japan)
Instrument Team
Xiaojing Liu
Instrument Lead Scientist
+86-(0)21-20685511
Weiqing Xu
Beamline Scientist
+86-(0)21-20684667
xuwq1@shanghaitech.edu.cn
