Status of the AIRIX accelerator

Abstract

AIRIX is a linear induction accelerator that will be used for flash X-ray radiography. It will deliver a 20 MeV, 3.5 kA, 60 ns electron beam. This accelerator is now under installation at PEM. The injector, that produces a 3.5 kA, 4 MeV, 60 ns electron beam and 16 induction cells powered by 8 high voltage generators (250 kV per cell) are already operational. At this point, the AIRIX LIA has the same dimension than the PIVAIR prototype installed at CESTA [1]. This paper relates the electron beam characterization that we have made to compare the two accelerators. Those experiments consist first, on beam imaging to validate beam transport code at three points on the beam line. In a second time we measure the energy of the beam with the time-resolved spectrometer to control the acceleration of the beam and to precisely tune the chronometry of the machine. Finally, we measure the emittance of the beam with the Pepper-pot method to compare the value before and after acceleration. We will present also the accelerator update and the experiments we plan to do when the 64 induction cells and the 32 H.V. generators will be installed.

CCD camera system design for the beam diagnostic by using OTR

“…The dual peak asymmetry of OTR spectrum reduced with the growth of electron energy. When the Electron energy is 4 MeV , the dual peak differ more than 60%, while is 30 MeV, they differ less than 8% [3] . The distance between dual peak reduces with the growth of the energy, the reduction is approximately in direct proportion to γ −1 , so half-height width of the peak reduces with the increase of the energy.…”

Lifetime testing of Airix accelerating units

“…Each cell, schematized in Figure 1, is an assembly of an inductive core (7), two matched oil-insulated HV connections (3), a water-cooled solenoid (6) and two magnetic dipoles for beam deviation, all of those held together under vacuum (<10-5 mbar) in a stainless steel casing (5) [4].…”

“…Matching at the HV connection is achieved by a resistor (4) in parallel to the cell, while the feedthrough (8) itself separates the oil from the vacuum.…”

Direct measurement of the image displacement instability in a linear induction accelerator

“…Second, there must be a discontinuity within the accelerator walls such as accelerating gaps. This latter point makes the instability especially concerning for users of linear induction accelerators (LIAs) [4][5][6] and for present designers of new LIAs such as the Los Alamos National Laboratory, the Institute of Fluid Physics (China Academy of Engineering Physics) [7], and the Budker Institute of Nuclear Physics (Russian Academy of Sciences) [8].…”