RadiaBeam Systems, Santa Monica, California, USA
RadiaBeam, Santa Monica, California, USA
ANL, Argonne, Illinois, USA
MEPhI, Moscow, Russia
A thermionic RF gun is a compact and efficient source of electrons used in many practical applications. RadiaBeam Systems and the Advanced Photon Source of Argonne National Laboratory collaborate in developing of a reliable and robust thermionic RF gun for synchrotron light sources which would offer substantial improvements over existing thermionic RF guns and allow stable operation with up to 1A of beam peak current at a 100 Hz pulse repetition rate and a 1.5 μs RF pulse length. In this paper, we discuss the electromagnetic and engineering design of the cavity, and report the progress towards high power tests of the cathode assembly of the new gun.
RadiaBeam Systems, Santa Monica, California, USA
MEPhI, Moscow, Russia
A number of electron beam vacuum devices such as small radiofrequency (RF) linear accelerators (linacs) and microwave traveling wave tubes (TWTs) utilize slow wave structures which are usually rather complicated in production and may require multi-step brazing and time consuming tuning. Fabrication of these devices becomes challenging at centimeter wavelengths, at large number of cells, and when a series or mass production of such structures is required. A hybrid, metal-dielectric, periodic structure for low gradient, low beam current applications is introduced here as a modification of Andreev's disk-and-washer (DaW) structure. Compensated type of coupling between even and odd TE01 modes in the novel structure results in negative group velocity with absolute values as high as 0.1c-0.2c demonstrated in simulations. Sensitivity to material imperfections and electrodynamic parameters of the disk-and-ring (DaR) structure are considered numerically using a single cell model.
ANL, Argonne, Illinois, USA
RadiaBeam, Santa Monica, California, USA
Argonne National Laboratory is developing an Advanced Compact Carbon Ion Linac (ACCIL) in collaboration with RadiaBeam Technologies. The 45-meter long linac is designed to deliver up to 109 carbon ions per second with variable energy from 45 MeV/u to 450 MeV/u. To optimize the linac design in this energy range both backward traveling wave and coupled cell standing wave S-band structures were analyzed. To achieve the required accelerating gradients our design uses accelerating structures excited with short RF pulses (~500 ns flattop). The front-end accelerating structures such as the RFQ, DTL and Coupled Cell DTL are designed to operate at lower frequencies to maintain high shunt impedance. In parallel with our design effort ANL's RF test facility has been upgraded and used for the testing of an S-band high-gradient structure designed and built by Radiabeam for high pulsed RF power operation. The 5-cell S-band structure demonstrated 52 MV/m acceleration field at 2 μs 30 Hz RF pulses. A detailed physics design, including a comparison of different accelerating structures and end-to-end beam dynamics simulations of the ACCIL will be presented.
RadiaBeam, Santa Monica, California, USA
Novel radiographic imaging techniques [1] based on adaptive, intra-pulse ramped-energy short X-ray packets of pulses, a new type of fast X-ray detectors, and advanced image processing are currently some of the most promising methods for real-time cargo inspection systems. RadiaBeam Technologies is currently building the high-speed Adaptive Railroad Cargo Inspection System (ARCIS), which will enable better than 5 mm line pair resolution, penetration greater than 450 mm of steel equivalent, material discrimination over the range of 6 mm to 250 mm, 100% image sampling rate at speed 45 km/h, and minimal average dose. One of the core elements of ARCIS is a new S-band travelling wave linac with a wide range of energy control that allows energy ramping from 2 to 9 MeV within a single 16 μs RF pulse using the beam loading effect. In this paper, we will discuss the linac design approach and its principal components, as well as engineering and manufacturing aspects. The results of the experimental demonstration of intra-pulse energy ramping will be presented.
[1] A. Arodzero, S. Boucher, A. Murokh, S. Vinogradov, S.V. Kutsaev. System and Method for Adaptive X-ray Cargo Inspection. US Patent Application 2015/1472051.