The electron beam generated in a self-modulated laser-wakefield accelerator is characterized in detail. A transverse normalized emittance of 0.06 p mm mrad, the lowest ever for an electron injector, was measured for 2 MeV electrons. The electron beam was observed to have a multicomponent beam profile and energy distribution. The latter also undergoes discrete transitions as the laser power or p...

A low-energy plasma focus device was used as an electron beam source. A technique was developed to simultaneously measure the electron beam intensity and energy. The system was operated in Argon filling at an optimum pressure of 1.7 mbar. A Faraday cup was used together with an array of filtered PIN diodes. The beam-target X-rays were registered through X-ray spectrometry. Copper and lead line ...

In the beam pipe of the positron damping ring of the Next Linear Collider, electrons will be created by beam interaction with the surrounding vacuum chamber wall and give rise to an electron cloud. Several solutions are possible for avoiding the electron cloud, without changing the bunch structure or the diameter of the vacuum chamber. Some of the currently available solutions for preventing th...

The accelerator safety interlock system (ASIS) for the X-ray free electron laser (XFEL) at SPring-8 protects personnel from radiation hazards. We developed an ASIS consisting of three interlock systems: a central interlock system (CIS), an emergency interlock system (EIS), and a beam route interlock system (BIS). The CIS and EIS monitor the safety equipment status and emergency stop buttons, re...

Introduction: In clinical electron beams, most of bremsstrahlung radiation is produced by various linac head structures. This bremsstrahlung radiation dose is influenced by the geometry and construction of every component of the linac treatment head structures. Thus, it can be expected that the amount of the contaminated photon dose due to bremsstrahlung radiation varies among different linacs,...

The mechanism of electron multipacting in long bunched proton machine has been quantitatively described by the electron energy gain and electron motion. Some important parameters related to electron multipacting are investigated in detail. It is proved that multipacting is sensitive to beam intensity, longitudinal beam profile shape and transverse beam size. Agreements are achieved among our an...

In many accelerators running positively charged beams, ionization of residual gas and secondary electron emission in the beam pipe will give rise to an electron cloud which can cause beam blow-up or the loss of the circulating beam. One solution to avoid the electron cloud is to ensure that the vacuum wall has low secondary emission yield (SEY). The SEY of thin films of TiN and sputter-deposite...