68-5203-16_Specs_with_header.pdf

Minimum Specification for Acquisition of:

Multi-Beam Thermionic Electron Source

68-5203-16 PR Nbr:

Scope: Code 6850 requires engineering services (NRE) and fabrication of two custom thermionic electron sources built according to a Code 6850 electron optical design. The electron optical design specifies the dimensions of the critical electrodes once the electron source reaches thermal equilibrium (see Fig. 1).

Fig. 1 Shows a cutaway view of the thermionic electron source. The source consists of four individual electron emitters arrange in a circular pattern and the critical electrodes consist of (1) heater/emitter assembly, (2) focus electrode, (3) mod-anode and (4) anode-body.

Note that the electrode geometries shown in Fig. 1 are rendered as “floating” objects, i.e. the vacuum envelope, supporting structures and generic hardware associated with electron source fabrication has intentionally been left out. These mechanical (non-critical) details will be added by the vendor according to their best practices for manufacturing precision electron sources.

The vendor will complete the mechanical design, perform thermal analysis on it and fabricate two sources accordingly. Since the intent is to provide (2) prototype electron sources for the purpose of testing the NRL Code 6850 design, the vendor should be allowed the freedom to

3 4 pgilroy Typewritten Text pgilroy Typewritten Text pgilroy Typewritten Text pgilroy Text Box N00173-16-Q-0491 Attachment 1 select materials, design supporting structures and implement manufacturing procedures that reduce complexity and cost of the finished assemblies. The Minimum Specifications required by NRL Code 6850 shall be applicable to the electron optical performance of the sources as detailed below.

Minimum Specification for Thermionic Electron Sources

1. Minimum Emission Current (Ie): Ie (total) > 100 mA, Ie > 25 mA per emitter +/- 2 mA

2. Minimum Voltage Hold-Off (V): V(1) to all grounded structures > 6 kV, V(2) to V(1) > 10

V, V(3) to V(2) > 200 V.

3. Minimum Emission Current Density (Loading): J > 19 A/cm2 averaged over emitter area.

4. Alignment Tolerance: Geometric axes of emitters and the apertures in the focus electrode, mod-anode and anode shall be aligned to < +/- 0.001” when the source is at thermal equilibrium at a temperature to be determined by vendor's thermal analysis.

pgilroy Text Box N00173-16-Q-0491 Attachment 1