Test Bed Development
Our goals is simple:
1. Design a modular test bed Transmission Line (TL) for multipactor material characterization.
2. Will operate at multiple frequencies (~100-700 MHz)
3. Will be capable of multitone operation (> Dual frequencies) to aid comparison with theory
4. Will be capable of modulated signal input
5. Will be able to have different material samples in center region, including dielectrics
6. Chamber is configured so as to allow for fast change in target material and fast pump down ~10e-6 torr
Image above shows vacuum Transmission Line region in center. Top inset close up of electron gun. Bottom inset close up of modulated multitone electronics and amplifier.
Modular Multipactor Test Bed in Numerical Space
Our Co-Planar design relies heavily on :
1. Analytical theory
2. Numerical simulations
3. Previous development
We employ FDTD, PIC and commercial based multipactor code, as well as the ECSS multipactor tool for design guidance.
Image above shows typical dimensions for one version of our co-planar test bed. The Trasnmission Line has a conical entrance and exit to minimize reflection losses. The entire line is matched at 51 ohms to the input amplifier at 50 ohms.
Top inset shows a PIC simulation of similar goemetry. Bottom inset shows growth curver for electrons.
Electron Detection
We are now in the trial part of our experiments (Jan 2022) in detecting electrons. We have a bidirectional coupler that could detect impedance mismatch in an event tied to a fast (2 GHz) digitizer. We have a hyperspectral camera focused on the center region, we will also field an electron multiplier in vacuum and a Silicon Photomultiplier tied with an electron sensitive organic plastic scintillator-- A SiMP that captures blue light!!
MORE TO COME SOON!!!