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LINAC COHERENT LIGHT SOURCE Atomic, Molecular and Optical Science AMO Overview Intense short pulses of X-ray radiation created by the LCLS free electron laser (FEL) will interact with electrons in the sample being illuminated to create states of matter that have not been observed previously. The goal AMO Main Contacts: Name Phone Email John Bozek Instrument Scientist 650-926-5091 [email protected] Name Phone Email Christoph Bostedt AMO Instrument Scientist 650-926-2591 [email protected] Name Phone Email Jerry Hastings LUSI Project Director 650-926-3107 [email protected] of the Atomic, Molecular and Optical (AMO) science instrumentation at the LCLS is to explore the interaction of this intense radiation with the simplest forms of matter, namely atoms and molecules, to gain an understanding of how their electronic structure responds. Femtosecond X-ray pulses from the LCLS also offer the opportunity to follow the evolution of chemical reactions on their natural time scales using well established and powerful tools such as ion, photoelectron, Auger and X-ray emission spectroscopy. AMO at the LCLS LCLS Complex A suite of instrumentation including focusing optics, gas delivery systems, electron, ion and photon spectrometers and a synchronized high-power laser are currently being designed for the AMO end-station. AMO Complete Assembly AMO/Near Hall/Hutch 1 AT O M I C , M O L E C U L A R A N D O P T I C A L S C I E N C E AMO Characteristics Scientific Capabilities Scientific Application Atomic, molecular and optical science with ultrafast and ultraintense x-rays at the lcls Techniques Electron time-of-flight spectroscopy Ion time-of-flight spectroscopy Ion imaging Ion momentum spectroscopy X-ray emission spectroscopy Sample Environment Skimmed supersonic pulsed gas jet Photon Beam Properties Focusing Capability Elliptically bent Kirkpatrick-Baez mirrors Beam Size at Sample ~1-2 μm at interaction region Energy Range 825-2000 eV Energy Resolution ΔE/E ~0.2% (inhomogeneous fel bandwidth) (no monochromator) Diagnostics Magnetic Bottle Electron Spectrometer Measures the photon energy and bandwidth of the X-rays with a high efficiency electron spectrometer Pulse Energy Monitor Measures the energy of each pulse Beam Screens Measures position and size of beam in the far field AMO Science Focus The interaction of ionizing radiation with matter has been a topic of much study since Hertz observed (1887) and Einstein described (1905) the photoelectric effect. While the mechanisms of excitation and ionization following the illumination of a sample with a weak beam of X-rays are well understood, little is known about the processes which occur when an intense beam of X-ray radiation strikes a target. Novel multi-electron processes are expected to occur and states of matter never before seen created. The goal of the AMO instrument is to study the interaction of the intense, short pulses of X-rays from the LCLS with the simplest forms of matter; atoms, molecules and clusters, to expand the understanding of which processes are important at different intensity regimes. The extremely short pulses of X-rays from the LCLS provide a unique capability to study chemical processes at their natural time-scale. X-rays, such as those produced by the LCLS, interact with electrons in matter, exciting or ionizing them or scattering from them. Electron dynamics occur on the attosecond time-scale, much faster than the duration of the LCLS pulse. Nuclear dynamics (the motion of nuclei in a molecule) occur on the femtosecond time scales, however, a time The unique capabilities of the LCLS AMO instrument will address a wide variety of science such as: • Investigate Multiphoton and High-field X-ray Processes in Atoms, Molecules and Clusters • Multi-photon Ionization/ Excitation in Atoms/Molecules/ Clusters • Accessible Intensity on Verge of High-field Regime • Study Time-resolved Phenomena in Atoms, Molecules and Clusters Using Ultrafast X-rays • Inner-shell Side Band Experiments • Photoionization of Aligned Molecules • Temporal Evolution of State-prepared Systems molecule adjusts to the changing nuclear structure. Furthermore, photoion- The AMO instrument is separated into four vacuum chambers, each with their own specific purpose: ization of inner-shell electrons provide a site-specific probe of the electronic • Single Pulse Shutter structure of a molecule, i.e. allowing electrons from a carbon atom to be dif- • Focusing Optics ferentiated from those of an oxygen atom. The LCLS is therefore a powerful tool • High-field Physics End-station scale that the LCLS is ideally suited to study, and the electronic structure of a for studying the motion of atoms in molecules reactions initiated by an external trigger (i.e. laser). • Diagnostics Chamber In addition, a ~2mJ 120Hz 800nm pulsed laser (with harmonics) will be provided along with a control and data acquisition system capable of measuring data from each pulse. AT O M I C , M O L E C U L A R A N D O P T I C A L S C I E N C E AMO Assembly Breakdown Single Pulse Shutter Focusing Optics Slow Speed Camera P Slow Speed Camera P AMO Complete Assembly P KB Mirror 1 and 2 Scanning Slits (2) with YAG Paddle Turbo Single Pulse Shutter with Beam Paddle Ion Pump 1 Ion Pump TSP P Primary Pump 1 2 2 High-field Physics End-station P Electron Spectrometers 5x X-ray Emission Spectrometers Slow Speed Camera Laser Introduction Mirror Turbo Gas Jet P Telescope and Camera Bypass Valve P P P Primary Pump 3 4 RGA 1 of 3 Ion Spectrometers Differential Pumping Up to Air Valve P Slow Speed Camera 3 Beam Focus Paddle Removeable Beam Stop Turbo Beam Viewing Paddle P Sample Primary Pump Diagnostics Chamber P Primary Pump 4 X-ray Emission Spectrometers P P 120 Hz Cameras Gas Needle P Fixed Beam Stop RGA Up to Air Valve Up to Air Valve Differential Pumping Magnetic Bottle Electron Spectrometer Turbo Turbo P Slow Speed Camera Turbo Beam Beam Viewing Viewing Screen Total Screen Power Measurement P Sample Primary Pump AT O M I C , M O L E C U L A R A N D O P T I C A L S C I E N C E Single Pulse Shutter: The first small chamber will house a single pulse shutter that can be used to allow only a single FEL pulse pass through to the experimental chambers. A millisecond shutter from azsol GmbH (http://www.azsol.ch/index.php?p=home&lg=en) will be incorporated into the vacuum chamber on a translation stage to allow insertion into the beam. Focusing Optics: Two elliptically bent mirrors will be used to image the FEL beam into the experimental chamber. Dynamically bent mirrors can be adjusted to focus the beam into either the interaction region in the high-field physics chamber or the diagnostics chamber, depending upon the experimental requirements. High-field Physics End-station: The main experimental chamber of the AMO instrumentation includes the majority of the experimental capabilities. A skimmed pulsed gas jet is used to introduce sample gas into the chamber where it will be ionized/excited by X-rays from the LCLS. Several spectrometers will detect the results of the interaction of the FEL radiation with the sample, including electron, ion and X-ray spectrometers. A set of five electron time-of-flight spectrometers will be arrayed around the interaction region to measure the energy and direction of the ejection of electrons from the sample. One of three possible ion spectrometers, either a simple timeof-flight, a velocity map imaging, or a momentum resolving ion spectrometer, will also be mounted simulataneously, providing a means of measuring both ions and electrons from each shot. Eventually two X-ray spectrometers will be available to measure fluorescence from the samples, although they will have to be fit in place of the electron spectrometers when in use. AT O M I C , M O L E C U L A R A N D O P T I C A L S C I E N C E Diagnostics Chamber: A separate diagnostics section is being designed to measure the parameters of the X-ray FEL on a pulse-by-pulse basis. A magnetic bottle electron spectrometer will be used to measure the photon energy and bandwidth of each pulse. Ce:YAG beam screens will be used to image the beam downstream of the focus and a thermal energy monitor used to monitor the intensity of each pulse. These tools are designed to provide information about each pulse to aid in the interpretation of the data obtained in the upstream chamber.