10ANP4 Cathode Ray Tube

A 10-inch round glass, special-purpose cathode ray tube featuring magnetic deflection, magnetic focus, a spherical-aluminized gray glass faceplate, and a P4 phosphor screen.

Overview

The 10ANP4 is a specialized, 10-inch round glass cathode ray tube designed for applications requiring magnetic deflection and magnetic focus. It features a spherical, gray glass faceplate with an aluminized screen. The "10ANP-" family of tubes is characterized by a narrow 7/8-inch neck diameter, a miniature E9-37 base, and a 6.3-volt, 300 mA heater.

The specific designation 10ANP4 utilizes the P4 phosphor, which provides a white fluorescence with medium persistence, making it suitable for standard monochrome display and imaging applications. Other variants in the same family are supplied with alternative phosphors (such as P7, P16, P19, and P25) to meet different persistence and spectral requirements.

Optical and Screen Characteristics

The 10ANP4 is constructed with a spherical-aluminized gray glass faceplate. The aluminized backing enhances screen brilliance and prevents ion burn, while the gray glass improves contrast under ambient lighting conditions.

The primary optical characteristics of the 10ANP4 are determined by its P4 phosphor screen:

Phosphor Family Comparisons

While the 10ANP4 is equipped with the medium-persistence P4 white phosphor, the 10ANP- envelope and electron gun assembly can be configured with other screen phosphors to suit specific application demands:

• P7: Blue fluorescence with yellow phosphorescence and long persistence.
• P16: Violet fluorescence with extremely short persistence.
• P19: Orange fluorescence with orange phosphorescence and long persistence.
• P25: Orange fluorescence with orange phosphorescence and long persistence.

Note on Screen Protection: For variants utilizing high-persistence or specialized phosphors like P16, P19, and P25, the screen can be permanently damaged if the electron beam current density is allowed to rise too high. To prevent screen burning, minimum beam current densities must be maintained during operation.

Mechanical Specifications and Basing

The 10ANP4 features a compact physical design relative to its screen size, utilizing a narrow neck and a miniature base to minimize space requirements.

Physical Dimensions

• Overall Length: 16 Inches (Maximum)
• Outer Bulb Diameter: 10-1/2 ± 1/16 Inches
• Minimum Useful Screen Diameter: 9 Inches
• Neck Diameter: 7/8 Inch nominal (0.840" +0.056" / -0.030" actual)
• Deflection Angle (Approximate): 50 Degrees
• Reference Line to Anode Cap Distance: 2-1/4 ± 1/4 Inches
• Reference Line to Base Distance: 9-7/16 ± 1/8 Inches
• Reference Line to Neck Flare Transition: 2.880 Inches

The reference line of the tube is precisely determined by the point where the leading edge of a JEDEC G-112 reference line gauge (a cylinder measuring 2 inches in length with an inside diameter of 1.500" +0.003" / -0.000") stops along the neck flare.

Basing and Connection Layout

The tube utilizes an E9-37 miniature base and is wired according to the 9NB basing diagram. High-voltage anode connection is made via a recessed small cavity cap (J1-21) located on the side of the bulb.

Alignment and Handling Precautions

Proper mechanical alignment is critical for correct installation. The plane of the J1-21 anode cap passes halfway between Pin 1 and Pin 9 with an allowable tolerance of ±10 degrees. The cap is positioned on the same side of the envelope as Pins 1 and 9.

When installing the tube, a socket with a center opening must be used to clear the exhaust tubulation. Extreme care must be taken during handling to avoid damaging the exposed tubulation and to prevent bending the miniature base pins.

Electrical Ratings and Operating Conditions

The 10ANP4 operates with an indirectly heated cathode and requires a standard 6.3-volt heater supply.

Heater and Capacitance Data

• Heater Voltage: 6.3 Volts
• Heater Current: 0.3 Ampere ± 10% (300 mA)
• Direct Interelectrode Capacitances (Approximate):
  • Cathode to All Other Electrodes: 5 pF
  • Grid No. 1 to All Other Electrodes: 6 pF
  • Grid No. 2 to All Other Electrodes: 5 pF

Design Maximum Ratings

These ratings represent the absolute limits within which the tube must be operated to ensure reliability and longevity:

• Anode Voltage: 12,000 Volts dc (Maximum)
• Grid No. 2 Voltage: 450 Volts dc (Maximum)
• Grid No. 1 Voltage:
  • Negative Bias Value: 200 Volts dc (Maximum)
  • Positive Bias Value: 0 Volts dc (Maximum)
  • Positive Peak Value: 0 Volts (Maximum)
• Peak Heater-Cathode Voltage:
  • Heater Negative with Respect to Cathode: 180 Volts (Maximum)
  • Heater Positive with Respect to Cathode: 180 Volts (Maximum)

Typical Operating Conditions

Under typical operating conditions, the tube is set up with the following parameters:

• Anode Voltage: 9,000 Volts dc
• Grid No. 2 Voltage: 250 Volts dc
• Grid No. 1 Voltage: -15 to -45 Volts dc (for visual extinction of the undeflected focused spot)
• Focusing Coil Current (Approximate): 40 to 60 mA dc
• Linewidth A: 0.013 Inch (Maximum)
• Spot Position (Undeflected): Within a 1/2-inch radius circle concentric with the center of the tube face (when the tube is shielded)
• Modulation: 40 Volts (Maximum)

The focusing coil current is measured at an accelerator (anode) current of 100 µA, using a JEDEC Focus Coil No. 127 (or equivalent) with its air gap center located 2-1/2 inches from the reference line. Linewidth and modulation values are measured per the MIL-E-1 specification at an anode current of 400 µA.

Circuit Design and Safety Considerations

Performance and Voltage Limits

The performance of the 10ANP4 is highly dependent on the accelerator (anode) voltage. Both brilliance and image definition decrease as the accelerator voltage is reduced. To maintain acceptable display quality, the accelerator voltage should not be operated below a minimum of 7,000 volts.

To prevent damage to the control grid circuit and maintain bias stability, the Grid No. 1 circuit resistance must not exceed a maximum value of 1.5 Megohms.

X-Ray Radiation Warning

When operating the 10ANP4, safety precautions regarding ionizing radiation must be observed. X-ray radiation shielding may be necessary to protect personnel from prolonged exposure at close range if the tube is operated at voltages higher than the manufacturer's Maximum Rated Anode Voltage (12,000 Volts dc) or 16,000 volts, whichever is less.

Technical Summary

The 10ANP4 is a 10-inch round glass, special-purpose cathode ray tube featuring magnetic deflection and magnetic focus. It is equipped with a spherical-aluminized gray glass faceplate and a P4 white phosphor screen that provides medium persistence. Operating with a 6.3 V, 300 mA heater, the tube utilizes an E9-37 miniature base with a 9NB basing configuration and a J1-21 recessed small cavity cap for the high-voltage anode connection.

With a design maximum anode voltage rating of 12,000 Volts dc and a typical operating anode voltage of 9,000 Volts dc, the 10ANP4 delivers high-contrast, sharp displays with a maximum linewidth of 0.013 inch under specified MIL-E-1 test conditions. Designers must ensure that the accelerator voltage is kept above 7,000 Volts to preserve brilliance and definition, limit the Grid No. 1 circuit resistance to 1.5 Megohms, and implement adequate X-ray shielding if operating near or above maximum voltage limits.