报告一：

报告题目：APEX, The Advanced PhotoInjector EXperiment at the Lawrence Berkeley National Laboratory

报 告 人：Fernando Sannibale （Lawrence Berkeley National Laboratory）

报告时间：9月14日（星期三）上午14:00-15:00

报告地点：张江园区办公楼109会议室

报告简介：

Science needs in the last decade have been pushing the accelerator community to the development of high repetition rates (MHz/GHz-class) linac-based schemes capable of generating high brightness electron beams. Examples include X-ray FELs; ERLs for light source, electron cooling and IR to EUV FEL applications; inverse Compton scattering X-ray or gamma sources; and ultrafast electron diffraction and microscopy. The high repetition rate requirement has profound implications on the technology choice for most of the accelerator parts, and in particular for the electron gun. The successful performance of the GHz room-temperature RF photo-injectors running at rates <~100 Hz, cannot be scaled up to higher rates because of the excessive heat load that those regimes would impose on the gun cavity. In response to this gun need, we have developed at the Lawrence Berkeley National Laboratory (LBNL) the VHF-Gun, a lower-frequency room-temperature RF photo-gun capable of CW operation and optimized for the generation of the quality beams required by MHz-class X-ray FELs. The Advanced Photo-injector EXperiment (APEX) was funded by the US Department of Energy and built at LBNL for qualifying the VHF-gun. This year, a series of beam tests successfully demonstrated the capability of the electron source of operating at the challenging performance required by high repetition rate X-Ray FELs. Based on these results, LBNL is presently fabricating a second VHF-Gun to drive the injector of the LCLS-II, the SLAC high repetition rate X-ray FEL under construction at Stanford. APEX is also presently operating as the electron source for a multi-year high repetition rate ultrafast electron diffraction program at LBNL. This talk includes a description of the facility and of the achieved results, and a brief discussion on possible future activities.

报告二：

报告题目：APEX, highlights and lesson learned over five year of experience

报 告 人：Fernando Sannibale （Lawrence Berkeley National Laboratory）

报告时间：9月15日（星期四）上午9:30-10:30

报告地点：嘉定园区学术活动中心102会议室

报告简介：

A high repetition rate, MHz-class, high-brightness electron source is a key element in future high-repetition-rate x-ray free electron laser-based light sources. The VHF-gun, a novel low frequency radio-frequency gun, is the Lawrence Berkeley National Laboratory (LBNL) response to that need. The gun design is based on a normal conducting, single cell cavity resonating at 186 MHz in the VHF band and capable of continuous wave operation while still delivering the high accelerating ?elds at the cathode required for the high brightness performance. The VHF-gun was fabricated and successfully commissioned in the framework of the Advanced Photo-injector EXperiment, an injector built at LBNL to demonstrate the capability of the gun to deliver the required beam quality. The basis for the selection of the VHF-gun technology, design features, and fabrication techniques are presented jointly with lesson learned during the different phases of the project.

报告人简介：

After completing his studies in Physics at "la Sapienza" University in Rome in 1991 ("Laurea" in physics with maximum grade), Fernando Sannibale worked for 10 years at the Frascati laboratories of INFN in Italy as an accelerator physics researcher in the framework of DAFNE, the Frascati positron/electron collider. During this period he covered leadership roles and was responsible for the main electron/positron linac and for development of a number　of beam diagnostics systems. He also was an active player during the commissioning phase of the project. In 2001, he moved to the Lawrence Berkeley National Laboratory in Berkeley California as part of the Accelerator Physics group of the Advanced Light Source. He is now a Senior Scientist in the same group and is also the Principal Investigator of the APEX project, the injector test facility developed at LBNL to characterize the performance of the VHF-Gun, a new concept high-repetition rate high-brightness electron source optimized for X-ray FEL applications. A close version of the VHF-Gun is being built at LBNL and will operate in the injector of the LCLS-II, the high-repetition rate X-ray FEL in construction at Stanford. Since 2013, Fernando became a fellow of the American Physical Society, for his contributions in the understanding of coherent synchrotron radiation in storage rings and for the development of high brightness electron sources. His present main fields of research include, high brightness electron sources and physics of electron storage rings.