Electron gun for a high-power X-band magnicon amplifier

100 MW electron gun for a 34.3 GHz magnicon

“…1 and Ref. 2), two stage compression is used [4], as proven for the 7 GHz magnicon [5], and for the 11.4 GHz magnicon [6]. Compression in this gun is only partially electrostatic (500:1), since more than this would lead to a higher electric field at the focus electrode; and would require a magnetic field of about 13 kG at the edge of the pole piece, leading to saturation in the iron [4].…”

“…To suppress this emission in the gun for the 11.4 GHz magnicon [6] an electrically isolated focus electrode biased negative with respect to the cathode was used. However, it is technically complex to realize this arrangement.…”

High-power high-convergence electron gun for an 11.424-ghz pulsed magnicon

“…The initial design was developed by True [6] using DEMEOS [7]. The final design optimization [8] was carried out using the SUPERSAM code [9]. Both codes provide comparable results, but SUPERSAM gives much smaller numerical noise, allowing one to make more precise simulations of "near-cathode" effects and providing accurate calculations of the beam matching with the realistic magnetic field of the magnicon magnetic system, which is obtained from the SAM code [10].…”

Status of X-band pulsed magnicon project

“…phase of the beam scalloping are in excellent agreement with the simulation result, which indicate that the beam is axially symmetric, but the maximum beam diameter exceeds the calculated value by 15-20%. One of the possible reasons for this discrepancy is that in this design the cathode and focus electrode are mounted on separate stems [5] and have different thermal expansion, which is not known with precision. Consequently, some uncertainty in the gun geometry exists even once the true perveance is measured.…”

“…The tube consists of an electron gun, ~6.5 kG solenoid, RF circuit and collector insulated from ground. The 500 kV diode gun is designed to produce a beam area compression of 2500:1 and a beam diameter in the magnet of about 1.5 mm [5]. The complete RF circuit has six 5.712 GHz TM 110 deflection cavities (a drive cavity, three gain cavities and two penultimate cavities), followed by an 11.424 GHz TM 210 output cavity.…”