Fast beam monitor diamond-based devices for VUV and X-ray synchrotron radiation applications

Abstract

The improved performance of third-generation light sources and the advent of next-generation synchrotron radiation facilities require the use of extremely precise monitoring of the main photon-beam parameters, such as position, absolute and relative intensity, and temporal structure. These parameters, and associated real-time feedbacks, are fundamental at the beamline control level and at the machine control level, to improve the stability of the photon beams and to provide bunch-to-bunch quantitative information. Fast response time, high radiation hardness and visible-blind response are main features of photonbeam monitors for VUV and X-ray synchrotron radiation beamlines; hence diamond-based detectors are outstanding candidates. Here, results are presented of an extensive measurement campaign aiming at optimizing the capabilities of diamond detectors to discern time structures below the 100 ps timescale. A custom-built device has been fabricated and tested at the Italian Synchrotron Radiation Laboratory Elettra in Trieste. The results obtained show that diamond is an excellent material for ultra-fast photon pulses with picosecond time resolution; finally the possibilities for application at freeelectron laser sources are discussed. research papers 388 Michele Di Fraia et al. Fast beam monitor diamond-based devices J. Synchrotron Rad. (2019). 26, 386-392 Figure 2Bode plot of the reflection coefficient S 11 (blue: amplitude; red: phase) of the device model shown in Fig. 1 up to 5 GHz.

Study of gain, noise, and collection efficiency of GaAs SAM-APDs single pixel

“…Compared to silicon devices, III-V compound semiconductors, such as GaAs, have some unique properties, such as a higher density, atomic number and electron mobility, which result in higher detection efficiency and shorter response times. Thanks to these characteristics, in recent years, GaAs, as well as wide-band gap materials such as CVD diamond [1,2] and SiC [3] have been studied as Si alternatives for the production of X-ray detectors.…”

Synchrotron Radiation Study of Gain, Noise, and Collection Efficiency of GaAs SAM-APDs with Staircase Structure

“…Thanks to the characteristics listed above, in recent years, GaAs [20], as well as wideband gap materials, such as CVD diamond [21,22] and SiC [23] or Al x Ga 1−x As [24], have been studied as Si alternatives for the production of X-ray detectors. In particular, there is growing interest in high-energy fluorescence spectroscopy with GaAs-based detectors [25], not only for the aforementioned higher efficiency compared to silicon but also for the possibility of working at room temperature, as opposed to the detectors currently used for high energies, based on germanium, which require liquid nitrogen cooling.…”