Liquid Nitrogen Dewar and Cold Trap for Ultra-High Vacuum (UHV)

The Liquid Nitrogen Dewar and Cold Trap is a double-walled, vacuum-insulated LN₂ dewar designed for ultra-high vacuum (UHV) applications. It features a DN40CF mounting flange, a DN16CF side port and a cold plate with four M3 threaded holes arranged in an 18 × 18 mm square pattern for mounting in-vacuum equipment.

Available with an optional pre-assembled heat exchanger, integrated Kapton heater and Pt100 temperature sensor, the cold trap can be used as a cryogenic UHV booster to significantly accelerate pump-down in vacuum transfer chambers.

Liquid Nitrogen Dewar

The vacuum-insulated dewar has a filling capacity of approximately 0.5 L of liquid nitrogen (LN₂), or approximately 0.4 L when using the supplied foam cap.

The dewar is manufactured using UHV-compatible materials and features a DN40CF (2.75") mounting flange and a DN16CF (1.33") side port.

A thermal insulation sleeve, foam cap and dewar cover are included.

Optional Heat Exchanger, Heater and Temperature Sensor

The cold trap is available with or without a pre-assembled heat exchanger, Kapton heater and Pt100 temperature sensor.

When equipped with the heat exchanger, the cold trap acts as a cryogenic pump by trapping residual gases on its cooled surfaces. In combination with a turbomolecular pump, it can significantly improve pump-down performance and reduce the time required to establish UHV conditions.

This configuration is particularly suitable for UHV sample transfer applications, including the Fast Pump Down Dock and portable UHV Suitcase systems.

After filling the dewar with liquid nitrogen, the heat exchanger cools down within a few minutes. In combination with the Fast Pump Down Dock (VSCT40), a pressure of approximately 1 × 10⁻⁸ mbar can be reached within 30 minutes under suitable operating conditions.

This eliminates the need for conventional bakeout during routine sample transfers and prevents unnecessary heating of the connected UHV Suitcase.

A single LN₂ filling provides approximately three hours of cooling.

Heat Exchanger Specifications

Heat Exchanger: Aluminium cooling blocks with OFHC copper core

Cooling Temperature: Approximately 80 K

Pump-Down Time: Approximately 30 minutes to 1 × 10⁻⁸ mbar when used with VSCT40

Integrated Kapton Heater

The integrated resistive Kapton heater enables rapid warm-up of the cold trap after cryogenic operation. Temperature is monitored using the integrated Pt100 sensor.

Minimum Operating Temperature: −200 °C

Maximum Operating Temperature: +80 °C

Maximum Rated Power: 90 W

Heater Resistance: Approximately 5.6 Ω

Recommended Operation: Constant-current mode at 4 A (approximately 22.5 V)

Temperature Sensor: Pt100

Electrical Feedthrough: DN16CF, 6-pin miniature feedthrough

Electrical Connection and Accessories

The integrated Kapton heater and Pt100 temperature sensor can be operated using either a suitable laboratory power supply or a dedicated heater controller.

Two different connection cables are available separately, depending on the selected control system.

Connection Cable for Laboratory Power Supply

Designed for connecting the Kapton heater to a suitable laboratory power supply and the Pt100 temperature sensor to external measurement equipment.

Connection Cable for Heater Controller

Designed for direct connection to a compatible heater controller, allowing integrated heater operation and temperature monitoring.

Important: Connection cables, laboratory power supplies and heater controllers are not included and must be ordered separately.

Scope of Delivery

Without Heat Exchanger, Heater and Temperature Sensor

The dewar is supplied with a DN40CF mounting flange, DN16CF side port with blank flange, thermal insulation sleeve, foam cap and dewar cover. No electrical feedthrough or internal heat exchanger assembly is included.

With Heat Exchanger, Heater and Temperature Sensor (Pre-Assembled)

The dewar is supplied with the pre-assembled heat exchanger, integrated Kapton heater, Pt100 temperature sensor and DN16CF electrical feedthrough, together with the thermal insulation sleeve, foam cap and dewar cover.

Connection cables are not included in either configuration and must be selected separately according to the intended power supply or heater controller.