Novel Single-Shot Diagnostics for Electrons from Laser-Plasma Interaction at SPARC_LAB

Abstract

Nowadays, plasma wakefield acceleration is the most promising acceleration technique for compact and cheap accelerators, needed in several fields, e.g., novel compact light sources for industrial and medical applications. Indeed, the high electric field available in plasma structures (>100 GV/m) allows for accelerating electrons at the GeV energy scale in a few centimeters. Nevertheless, this approach still suffers from shot-to-shot instabilities, mostly related to experimental parameter fluctuations, e.g., laser intensity and plasma density. Therefore, single shot diagnostics are crucial in order to properly understand the acceleration mechanism. In this regard, at the SPARC_LAB Test Facility, we have developed two diagnostic tools to investigate properties of electrons coming from high intensity laser-matter interaction: one relying on Electro Optical Sampling (EOS) for the measurement of the temporal profile of the electric field carried by fast electrons generated by a high intensity laser hitting a solid target, the other one based on Optical Transition Radiation (OTR) for single shot measurements of the transverse emittance. In this work, the basic principles of both diagnostics will be presented as well as the experimental results achieved by means of the SPARC high brightness photo-injector and the high power laser FLAME.

Characterization of self-injected electron beams from LWFA experiments at SPARC_LAB

“…Electrons produced with the FLAME laser were mainly used to perform diagnostic tests, based on betatron [23,24] and optical transition radiation [25,26,27].…”

Accurate spectra for high energy ions by advanced time-of-flight diamond-detector schemes in experiments with high energy and intensity lasers

“…During the experiment two main diagnostics were employed. An Electro-Optical Sampling (EOS) device was used to measure the longitudinal profile of the accelerated electron bunches 9,[45][46][47] Accelerated ions were detected by a CVD diamond detector mounted at the end of a 105 cm long TOF line placed behind the target, as shown in Figure 1c.…”

Single-shot electrons and protons time-resolved detection from high-intensity laser–solid matter interactions at SPARC_LAB

“…Here, their electric field can induce a local birefringence that, in turn, can be probed by a laser beam. Previous works have shown the feasibility of this diagnostic as a fast electron monitor [20, 21] and that electro-magnetic pulses are generated in this kind of interaction [22] . In particular, in the spatial encoding scheme [23] , the longitudinal distribution of the electrons can be mapped in the transverse profile of the probe laser.…”