High-vacuum electron tube with divergent electron gun aimed at a fluorescent screen partially obscured by a Maltese cross. For demonstrating the linear propagation of electrons in the absence of applied electromagnetic fields by projecting the shadow of a Maltese cross onto the fluorescent screen. Application of a magnetic field using the Helmholtz Coils (B8A49475) allows for students to study the fundamental science of electron optics, such as beam focusing.

The tube comprises of the standard spherical glass body with cylindrical neck, a diode electron gun with a filament and cylindrical anode connected to 4mm sockets in the plastic cap, a metal Maltese cross mounted in the centre of the sphere (connected via a 4mm plug in one of the side caps) and a phosphor coated screen.

Technical Specifications:

• Maximum filament voltage: =7.5V AC/DC
• Maximum anode voltage: 5 kV
• Anode current: 0.18mA at 4kV

Requires the following equipment to operate:

• B8A49463 - Universal Stand
• B8R02653 - EHT Power Supply - to power the anode
• B8R07149 - EHT Experiment Leads (3 required)
• B8G85458 - Bench Power Supply - to power the filament
• B8R06545 - 4mm Leads
• B8A49475 - Helmholtz Coils (Optional)
• B8G85483 - College Power Supply Unit - to power the optional Helmholtz Coils