100 MW electron gun for a 34.3 GHz magnicon

Abstract

A 100 MW advanced Pierce gun is described that was built for a 34.3 GHz magnicon amplifier. The gun has a computed beam diameter of ~0.9 mm when matched into a 13 kG magnetic field. The diameter of the cathode is 50 mm. Hence, the beam area compression ratio is ~3000:1.

Conceptual design report: a ring-based electron cooling system for the EIC

“…and reliable operation at high repetition rate at small breakdown rate. However, the maximal electric field there does not exceed 15 MV/m, which is close to acceptable [25][26][27]. The field at the anode nose of ~20 MV/m is also acceptable.…”

“…Operate at much lower beam area compression than the guns of Ref. [25][26][27], while keeping the same concept (Figure 33); c. Use micro-perveance ~1.-1.5 micro-perv. Table 6 shows the main gun parameters (the gun voltage -U, the beam pulsed power -Ppulsed and the beam average power -Paverage ) for different values of micro-perveance Pμ at the beam current of 50 A. Micro-perveance of 0.3 μperv looks reasonable, considering that even higher micro-perveance (~1.2 μperv) was used successfully for the gun presented in Ref.…”

“…The gun has a modest compression ratio with reasonable surface electric fields, which is required at high repetition rate. In order to obtain reasonable cathode lifetime (20,000-30,000 hours), the dispenser cathode diameter is chosen to be 25 mm, limiting loading to 12 A/cm 2 , which is the same as in the gun for 34 GHz magnicon [27]. Taking into account the cathode current density inhomogeneity this is the maximal current density necessary for anode aberration compensation [25].…”

“…The dispenser cathode has the operating temperature of 1050 C, which provides acceptable normalized thermal emittance of < 4 μm. The cathode has the surface roughness, which contribution to the effective beam temperature ΔT may be estimated by the following formula [27]:…”

Modified Magnicon for High-Gradient Accelerator R&D

“…The gun dynamics are well known, and its behavior is understood and the performance has been described in several publications [1,2]. Even though the gun was designed for 500 kV, it operates well in the range 460 -475 kV when the repetition rate is low; with high repetition rates (and especially with long pulses), the gun operates well at voltages at or below 450 kV.…”