USM1800 Cryogen-Free Low Temperature UHV Scanning Probe Microscope
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SPM System Specs.
Published Papers
PDF SPM System Specs.
Realization of STM with atomic resolution below 6K by mechanical refrigeration
Continuous cooling for long periods of time without the use of scarce liquid helium

The new closed-cycle USM1800 LT UHV SPM is now part of the UNISOKU SPM product family! The USM1800 provides sample temperatures below 6K, and the cryogen-free cooling system achieves ultimate SPM performance at low temperature while allowing interruption-free measurement conditions.
Features
- Sample temperature below 6K (when optical window shielding is closed)
- State-of-the-art SPM platform with atomic resolution imaging (qPlus® AFM is available as an option)
- Optical access and in-situ deposition capabilities (inertial-driven lens stages on the SPM platform are available as an option)
Applications
- Upgrades for LT-STMs with liquid He reservoir possible
- Observation of quasi-particle interference patterns by tunneling spectral mapping
- Observation of surface adsorption structure using in-situ deposition capabilities
- Studies of photo-induced phenomenon in combination with simultaneous SPM measurements
Schematic view of the USM1800 system

Cooling time: <6K in 24 hours![]()
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Temperature stability @ 5.2K![]()
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STM image (Vs=+300mV)![]() |
dI/dV mapping (20mV)![]() |
All pixel STS measurement during STM imaging. On HOPG condition : 35hours per a flame Drift rate : < 1nm/35hours |
Tunneling current noise spectrum![]() |
Superconducting gap of Pb![]() |
Nc-AFM NaCl atomic image at 6K![]()
Sample: NaCl (100) |
STM Au(111) atomic image at 5.6K![]()
Sample: Au (111) |
SPM structure |
Tip scanning type Coarse positioning for X,Y (ø 1 mm) and Z (5 mm) |
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Scan range | 1um × 1um at 6K |
Sample holder |
Bayonet style holder, Flag style holder (DC heating, EB heating, cleaving) ![]() |
Temperature |
<6K 1.5 year in each for Maintenance (Pulse tube refrigerator) |
Options |
Internal optical lens stages with 3D coarse positioning (NA~0.25) Tuning Fork NC-AFM |
Chamber structure |
Includes SPM observation chamber, preparation chamber, and loadlock chamber. In-situ UHV sample/probe holder transfers |
Recommended laboratory area | Floor space: 4m × 4m, Ceiling height: ø2.8m |
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Floor vibration level |
<1μm/s (rms) below 5Hz <3μm/s between 5-10Hz 5μm/s above 10Hz |
Preparation of equipment |
•Cooling water •Three-phase electric power |
PDF SPM System Specs.