Part evacuated electron tube, filled with neon at low pressure with a tangential and axial electron gun. For determining specific charge e/m from the diameter of the filament beam in the case of tangential bombardment and a perpendicularly aligned magnetic field, and observing spiral paths of electrons in the case of axial bombardment and a co-axial magnetic field.

The electron paths are rendered visible in the form of fine luminescent beams through impact excitation of the neon atoms.

The Dual Fine Beam tube is neon filled and electron beams may be observed throughout the full length of their travel within the tube, an orange glow being emitted during the gas/electron collisions. The tangential beam can be deflected by the use of Helmholtz Coils (B8A49475) to produce a completely circular path permitting e/m measurements to be made. Clear free path studies may be made and phenomena such as screen blanking due to charge build up on the screen my be observed. Within the tube are mounted two electron guns with indirectly hated cathodes, with one gun pointing along the axis of the tube, while the other is tangential to the axis, either gun being selected by a switch on the cylinder cap. The angle of projection from the guns is adjustable by means of miniature deflection plates near the gun outlets, a small potential being applied via 4mm connections at the side of the cylindrical neck. The end of the body has a phosphor coated screen for use with the axial gun.

Technical Specifications:

• Maximum filament voltage: 7.5 V AC/DC
• Anode voltage: 120-300V DC
• Maximum anode current: 30 mA
• Maximum deflection voltage: 50 V DC

Dimensions:

• Glass bulb: approx. 130 mm diameter
• Total length: approx. 260 mm

Requires the following products to operate:

• B8A49463 - Universal Stand
• HT Power Supply - to power the Anode (*coming soon*)
• B8G85458 - Bench Power Supply - to power the filament
• B8A49475 - Helmholtz Coils
• Stackable 4mm Plug Leads (black)
• Stackable 4mm Plug Leads (red)