Cryostat for
Sub-K Angular Resolution
Photoemission Spectroscopy (ARPES)

May 2008

He-3 condenses inside the 1K pot and enters the He-3 pot through a control impedance (used to limit the He-3 circulation). A hermetically sealed pumping station is employed to circulate the He-3, which then cools the He-3 pot to base temperature. An external gas handling system is equipped with a specially configured liquid nitrogen cold trap for continuous circulation of the He-3 gas. Due to the fairly high heat load from this experimental application (typically on the order of a few mW), the pumping station incorporates a high throughput Roots pump. This high capacity pumping station enables the system to achieve the lowest possible base temperature and highest cooling power. A gold plated OFHC copper cold finger is thermally connected to the He-3 pot through multiple flexible OFHC copper braids. These braids allow the cold finger to be rotated and translated in x-y directions.

Slots and apertures in the thermal shields provide access for the incoming photon beam and outgoing photoelectrons. The sample is located at the bottom of the cold finger, aligned directly toward the center of the slots for the electron analyzer.

In addition to operating continuously, this system can also be operated in the single shot mode.

Performance specification:

Please click here to download the typical performance chart (12 KB).  The downloaded file will be in PDF format which is viewable and printable with Acrobat Reader, a free plug-in utility from Adobe. To download the free acrobat plug-in software click here.

Main items:

• High efficiency liquid helium cryostat
• Liquid helium and liquid nitrogen level probes with digital monitor;
• 1K pot with thermometer
• He-3 impedance
• He-3 pot
• He-3 return line
• Gas handling system with hermetically sealed pumping station
• Electrical controlling circuit with over pressure protection
• Sample probe with linear and rotary motion
• Operation test

• Resistive wires and/or coaxial cables
• Fiber optics
• Computer controlled motorized 1K pot cryogenic needle valve
• Automatic temperature controller
• 1K pot pumping station
• Turbo pumping station

HE-3-BLSUHV-CF Bottom Loading Continuous Flow He-3 Cryostat 

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