Detailed knowledge of particle beam properties is of great importance to understand and push the performance of existing and next generation accelerators. This includes full knowledge of the particle distribution but also the characterization of femtocoulomb (fC) charge beams. We recently proposed a new phase space tomography method to reconstruct the full 5-dimensional (5D) phase space, i.e., the charge density distribution in all three spatial directions and the two transverse momenta. In this contribution, we first present the experimental demonstration of the method at the FLASHForward facility at DESY. This includes the reconstruction of the full 5D phase space distribution of an electron bunch, the use of this measured phase space to create a particle distribution for highly-realistic simulations, and the extraction of the 4D slice emittance. In a second part, we address the characterization of fC charge beams and present a diagnostic device based on silicon strip sensors that is able to measure the profile, time structure, and charge of beams with low charge density. The device demonstrates the applicability of silicon sensors as versatile beam instrumentation devices and can extend the capabilities of existing diagnostic devices to a new charge range.

Beam energy is a key parameter for free electron laser facilities (FELs). A commonly used nondestructive sys-tem uses a beam position monitor (BPM) to measure the bunch position in a magnetic bunch compressor. At the Shanghai Soft X-ray FEL facility (SXFEL), the chicane stripline beam position method is utilized for this pur-pose. However, this method relies on the initial bunch position before entering the chicane and has a limited linear region. A different non-destructive beam energy system, which measures the bunch flight time using two cavity-based bunch arrival time monitors, has been pro-posed and tested. This paper introduces the development of this system, including design details, build-up, and measurement results. Moreover, it also covers the compar-ison between the two different bunch energy measure-ment methods from several aspects: bunch position-based and bunch flight time-based.