Pre-fire problem in the abort kicker system have been last for a long time during the past 17 years of operation in RHIC. In order to limit the number of pre-fire events, a new system is implemented, installed and tested pre start of Run 17. We have installed two new Relay Control Units into the RHIC abort kicker system, one in Blue Ring and one in Yellow Ring. The scheme is included a simple...
We are testing a new radiographic source that uses a Marx bank with a one microsecond discharge time, coupled through a plasma opening switch (POS) to a plasma-filled rod-pinch diode (PFRP). The Hawk generator at NRL contains four Marx banks connected in parallel with an erected voltage of 640 kV and an output current of 700 kA with 1.2 microsecond quarter period into a short circuited 600...
This paper describes the software changes made to the data processing and display system for HERMES III accelerator at the Simulation Technology Laboratory (STL) at Sandia National Laboratories, New Mexico. The HERMES III accelerator is a gamma ray simulator producing 100kRad[Si] dose per shot with a full width half max pulse duration of ~25 nanoseconds averaging six shots per day. For each...
Beam breakup instability (BBU) is an important factor dominate the design of induction cell for high intensity linear induction accelerator. In this study, we optimize a magnetic tune for a conceptual induction accelerator. By using BREAKUP code and optimization algorithm, we estimate how BBU would affect the final beam spot size.
The China Spallation Neutron Source (CSNS) accelerator is designed to accelerate proton beam pulses to 1.6 GeV at 25 Hz repetition rate, striking a solid metal target to produce spallation neutrons. The accelerator provides a beam power of 100 kW on the target in the first phase [1]. The linac is designed with beam energy of 81 MeV and a peak current of 15mA. It consists of RFQ, two bunchers...
The performance of induction accelerator relies greatly on the design of the diode injector. By using TRAK (ray tracing code) and AMBER (slice PIC code), we designed a 2KA/2MeV diode injector and beam transportation from position of cathode to accelerator exit. We will present some design optimization strategies for diode injector and simulation results from TRAK and AMBER, particle loading...
Recently pulsed ion beam technology has been widely used for materials surface properties modification by the methods of ion implantation, ion plasma coatings deposition, and high energy ion beam energetic impact. For those materials processing applications, it is very important to develop the accelerator technology to generate ion beams with various ion species and high purity.
In order to...
National Security Technologies (NSTec) is developing dense plasma focus systems as intense pulsed neutron sources. Sandia National Laboratories participated in a limited number of experiments on an NSTec plasma focus. In collaboration with NSTec, Los Alamos National Laboratory, and Lawrence Livermore National Laboratory, we implemented additional electrical and X-ray image measurements in...
Velvet cathodes are widely used in field-emission electron diodes, in particular in induction accelerators used for flash X-ray radiography. The emision from velvet could be different from pulse to pulse in multi-pulse operation. As a consequence, we are revisiting the beam homogeneity and the emittance of the electron beam produced by velvet cathodes.
First, we used a single-pulse diode...
Due to their high saturation flux density, amorphous metallic alloys play a key role in linear induction accelerators that require ferromagnetic cores with sufficient volt-seconds to support multiple pulses. As both the shape of the material hysteresis curve and the core losses depend on the magnetization rate, dB/dt, measurements at various rates are necessary in any system model involving...
Different diagnostic tools were installed at the facility GESA-SOFIE in order to investigate the plasma behavior in the cathode-grid gap. A high-resolution fast CCD camera was used to monitor the formation and evolution of the cathode and grid plasmas. A streak camera with high dynamic range delivered information on the characteristics of the plasma motion. A complex modification of the...
Our team at Los Alamos National Laboratory has successfully employed Compton spectrometers to measure the x-ray spectra of intense radiographic sources, both continuous and flash. In this method, a collimated beam of x-rays incident on a convertor foil ejects Compton electrons. A collimator may be inserted into the entrance of the spectrometer to select the angular acceptance of the...
Electron multipactor is a major problem in accelerators, both in accelerating cavities associated with dark current and beam induced e-cloud problems, and in RF distribution systems leading to catastrophic damage or in mild cases performance decrease and phase shifting. In many scenarios passive mitigation techniques are preferred. Multipactor may be completely avoided if the effective SEY is...
In the design of pulsed relativistic accelerators, high power electrical pulses are generated in a volume that is filled with either high pressure gas or an oil to manage the high electric fields. However, the beam generating diode must operate in vacuum. The two sections, then, require an insulating barrier between them which is subject to very high electric fields. The vast majority of...
Multiple pulse flash radiography has been implemented worldwide utilizing various methods for many years. In the past decade, the method for achieving multiple pulse flash radiography has focused on utilizing a Linear Induction Accelerator (LIA) as the source. Various techniques, including diode isolation$^{1}$, have been used to accomplish the multiple pulse function.
Los Alamos National...
The Spallation Neutron Source (SNS) Proton Power Upgrade (PPU) will double the beam power from 1.4 to 2.8 MW by adding cavities in the superconducting linear accelerator (SCL) which will increase the beam energy from 0.97 to 1.3 GeV and by increasing the average Linac beam current from 26 to 38 mA. Provisions for an accelerator power increase were made in the original SNS project, and these...
The characteristics of opening switch plasmas initialized by two methods—cable guns and gas-fed Marshall guns— were compared spectroscopically, as part of an effort to understand the effect of multi-species plasma composition on opening switch performance. Anecdotal observations of slower switching with single-species plasma sources compared to multi-species sources have led to the hypothesis...
LEETCHI is an electron source designed to produce 140 keV, 5 A, 140 μs beams at a repetition rate of 50 Hz. The shot to shot and flat top current stability of this drive beam injector for CLIC has to be better than 0.1 % and a normalized emittance of 14 mm.mrad is expected. A test stand has been build which allows to diagnose and dump the beam produced by a thermionic cathode. The thermionic...
Under the UK and France Treaties related to “Defence and Security Co-operation” and to “joint radiographic / hydrodynamics facilities”, the joint Hydrodynamics Research Facility knows as EPURE is under construction at CEA VALDUC in France. At present, this facility is fully operational using a single radiographic axis configuration . By 2022, two others high performance X-ray machines will be...
The Gamma Beam System – the future user facility – is being built in the framework of the Extreme Light Infrastructure–Nuclear Physics (ELI-NP) project in Bucharest/Magurele, Romania. This is an advanced source of gamma rays based on Compton back-scattering. By collision of a visible laser beam and a high brightness relativistic electron beam, an intense (~1011 γ/s), brilliant γ beam (<0.5%...
We performed computerized analysis of the L-3 Communications Pulserad flash X-ray system (Model 42710A) for explosion analysis in our laboratory. As a Site Acceptance Test, X-ray generation experiments have been carried out to collect data on dose measurements according to distance and azimuthal angle. Based on the X-ray measurement data, the computational analysis of diode and the...
The beam dumping system of CERN's Large Hadron Collider (LHC) is equipped with fast solid state closing switches composed of a stack of ten series connected Fast High Current Thyristors (FHCT).
The triggering circuit of these switches consists of a 10:1 trigger transformer, with stray inductance of 5uH, powered by two redundant Power Trigger Modules (PTM) delivering 500 A peak gate current...
Observation shows that the electron orbit of the TLS (Taiwan light source) storage ring was greatly disturbed during the top-up injection process, both from BPM readings and profile monitor. The distortion duration exceeds the pulse lengths of both injection kickers and septum. It was speculated that one of the possible causes would be due to the eddy current effect induced by the leak field...
