The Cryogen-free Measurement System. CryoAdvance, Inc.

The optCRYO107vac is a combi cryostat with a sample in vacuum or inert gas atmosphere. Cooling agent is placed in a storage reservoir inside the cryostat body and is flowing into the sample room through the capillary to cool the sample chamber. The optCRYO107vac is a cryostat for the temperature interval from 2 K to 300 K. The sample is placed in vacuum chamber inside of the cryostat. The chamber temperature is stabilized by control of the heat exchanger temperature and gas flow regulation. The maximum vacuum in sample chamber is about 10-3 Torr. The sample is attached to the walls of the vacuum chamber. The low helium consumption (typically < 0.1 L/h) enables long operation time more than 20 hours. The optCRYO107vac can be used as a nitrogen cryostat on filling liquid nitrogen in helium reservoir.

Function

The cryostat has the liquid nitrogen and helium reservoirs. The nitrogen bath cools the outer radiation screen. Liquid helium (nitrogen) flows through the capillary into the pre-cooled cylindrical chamber. The heat exchanger is placed in the lower part of the pre-cooled chamber. The cryogenic liquid is evaporated on the heat exchanger and flows upwards. The cryogen gas temperature is regulated by electric power of the heat exchanger. The cylindrical vacuum chamber is placed inside of the pre-cooled chamber. The vacuum chamber walls are cooled by the cryogen gas flow. The flow rate of the cryogen gas through the pre-cooled chamber is electronically regulated by differential pressure regulator outside of the cryostat. The combined gas flow and heat exchanger regulation results in a low cooling agent consumption in the temperature interval from 4.2 K to room temperature. The temperatures below 4.2 K to 1.8 K can be reached by helium vapor pumping. Samples are top loading by the use of the sample holder.

Modification

optCRYO107-30vac

optCRYO107-40vac

Sample space, mm

30

40

He-reservoir, L

2.2

3.5

N-reservoir, L

2,5

4

Windows clear diameter, mm

15

15

Number of windows (transmission geometry)

2

2

Windows height above the cryostat bottom, mm

100

100

Window material

UV quartz

UV quartz

Length of cryostat tail, mm

180

180

Window-to-window distance for transmission geometry, mm

120

120

Temperature range, K

2 - 300

2 - 300

Temperature stability in the interval 4 - 50 K, K*

±0.05

±0.05

Temperature stability in the interval 50 - 300 K, K

±0.1

±0.1

Cool down time (to 4.2 K), min

40

40

Sample change time, min

20

20

He consumption at 4.2 K, L/h

0.12

0.14

He volume to cool the cryostat down to 4.2 K, L

1.8

2.2

Cryostat weight, kg

10.5

12.5

Complete system

1. optCRYO107vac cryostat.

2. Temperature controller tSTAT320 with Manostat.

3. Vacuum isolated transfer tube.

4. Sample holder.

Optionally

1. Optimization of windows configuration for optical experiments.

2. Maximal number of windows in horizontal plane – 5.

3. Windows material

• Sapphire.

• A2B6 (ZnSe, ZnS, CdTe etc).

• Other materials on request.

4. Aperture of an optic window up to 28°.

5. Clear diameter of an optical window up to 20 mm.

6. Low polarization windows with polarization ratio less than 1 %.

7. Angle between window axes is 45°, 90°, 180°.

8. Height of windows above the cryostat bottom from 65 to 400 mm.

9. Elliptical cryostat tail for experiments in magnetic field. Minimal distance between magnet poles is 65 mm.

10. Temperature sensors calibration table.

Additional equipment

1. Sample holder

• Sample rotation by 360° in vertical and horizontal planes.

• X or XY shift of the sample.

• Asymmetric sample position for microscopy.

• Up to 200 kg mechanical stress applied at helium temperatures.

2. He-transfer vacuum isolated tube

• Variable length connection.

• Flexible connection.

3. Tubes connections.

4. Sample rod with a universal flange.

5. Measuring heads, cassette heads.

6. 10-pin electric connections on the sample holder.

7. Helium or nitrogen storage dewar.

8. Dewar transport platform.

Key benefits

• Extremely low cooling agent consumption.

• He and N2 operation modes with one T-regulator and helium level gauge.

• Competitive price for the whole system.