Challenges and tolerances for a compact and hybrid ultrafast X-ray pulse source based on RF and THz technologies

T Vinatier,U Dorda,F Lemery,R W Assmann,B Marchetti

doi:10.1088/1742-6596/1596/1/012032

T Vinatier, U Dorda + Show 3 more

Open Access

https://doi.org/10.1088/1742-6596/1596/1/012032

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Abstract

We present an in-depth tolerance study and investigation of the main challenges towards the realization of a hybrid compact ultrafast (fs to sub-fs) X-ray pulse source based on the combination of a conventional S-band gun as electron source and a THz-driven dielectric-loaded waveguide as post-acceleration and compression structure. This study allows us determining which bunch properties are the most affected, and in which proportion, for variations of the parameters of all the beamline elements compared to their nominal values. This leads to a definition of tolerances for the misalignments of the elements and the jitter of their parameters, which are compared to the state-of-the-art in terms of alignment precision and stability of operation parameters. The most challenging aspects towards the realization of the proposed source, including THz generation and manufacturing of the dielectric-loaded waveguide, are finally summarized and discussed.

Highlights

Particle acceleration beyond the few-MeV level currently requires large infrastructures, of the order of several meters or tens of meters, due to the low operating frequencies and field amplitudes of the conventional RF accelerating structures
We present an in-depth tolerance study and investigation of the main challenges towards the realization of a hybrid compact ultrafast X-ray pulse source based on the combination of a conventional S-band gun as electron source and a THz-driven dielectricloaded waveguide as post-acceleration and compression structure
This study allows us determining which bunch properties are the most affected, and in which proportion, for variations of the parameters of all the beamline elements compared to their nominal values

Summary

Introduction

Particle acceleration beyond the few-MeV level currently requires large infrastructures, of the order of several meters or tens of meters, due to the low operating frequencies (a few GHz) and field amplitudes (a few tens of MV/m in the meter-long structures) of the conventional RF accelerating structures. RF-gun region For the RF-gun region, from the cathode to the THz linac entrance, the influence of jitters of the following parameters on the electron bunch properties at the ICS point are studied: RF-gun field amplitude, dephasing between the UV laser driving the gun and the RF-field, UV laser pulse energy, UV laser pointing and solenoid peak field. It shows (Figure 7 (g)) the distribution and partition functions of the bunch transverse offset at the ICS point, coming from a simulation of Case 1 where all the jitters previously mentioned and assumed in the paper are included. This means that the synchronization between the bunch and the laser only has to be better than a few ps, which is already demonstrated as achievable (see for example [26])

Other challenges

Manufacturing of the dielectric-loaded waveguide

Findings

Conclusions