The Cryogen-free Measurement System. CryoAdvance, Inc.

The optCRYO105 is universal helium/nitrogen cryostat for the temperature region 1.8 - 300 K. The optCRYO105 is a combi cryostat based on the advantages of bath and continuous flow cryostats. Cooling agent is placed in a storage reservoir inside of the cryostat body and is flowing into the sample room through the capillary to cool the sample. The sample is placed in a helium or nitrogen gas flow, the temperature is stabilized by variation of the heater power or the flow rate. The low cryogenic liquid consumption (typically < 0.1 L/h) enables long operation time of more than 20 hours. The helium optCRYO105 can be used as a nitrogen cryostat on filling liquid nitrogen in helium reservoir. Modifications optCRYO105N2 are the nitrogen cryostats.

All cryostat types of optCRYO105 family use tSTAT320 temperature stabilization system.

Function

The cryostat has the nitrogen and helium reservoirs. The nitrogen bath cools the outer radiation screen. Liquid cooling agent flows through the capillary into the sample room and evaporates on the heat exchanger. The helium (nitrogen) gas temperature is controlled by the electric power of the heat exchanger. In the temperature region 4.2 - 300 K the samples are placed in cryogen gas flow directed upwards. The gas flow rate is regulated by differential pressure regulator controlled by electronic unit outside of the cryostat. The combined gas flow and heat exchanger temperature regulation results in high temperature stability of the sample and in low cryogen consumption. The temperatures below 4.2 K to 1.8 K can be reached by helium vapor pumping. In this temperature region the samples are immersed in liquid helium. Samples are top loading by the use of sample holders.

Modification

optCRYO105-40

optCRYO105-50

Sample space, mm

40

50

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

140

140

Window-to-window distance for transmission geometry, mm

120

120

Temperature range, K

1.8 - 300

1.8 - 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

30

30

Sample change time, min

5

5

He consumption at 4.2 K, L/h

0.1

0.12

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

1.4

1.8

Cryostat weight, kg

10

12

Complete system

1. optCRYO105 cryostat.

2. Temperature controller tSTAT320 with Manostat.

3. Vacuum isolated transfer tube.

4. Sample holder.

Optionally

1. Special windows configuration for spectroscopy.

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

3. Windows material

• Sapphire.

• A2B6 (ZnSe, ZnS, CdTe etc).

• Other materials on request.

4. Maximal aperture of an optic windows - 32° (5 windows).

5. Clear diameter of an optical window up to 18 mm.

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

7. Additional window in bottom of the cryostat.

8. Minimal distance outer window-sample 10 mm for horizontal plane windows or for the window in bottom.

9. Asymmetric sample position in the sample holder. Maximal aperture of a window in the case of asymmetric sample position 90°.

10. Angle between window axes is 90°, 180°.

11. Height of windows above the cryostat bottom from 60 to 400 mm.

12. Elliptical cryostat tail for experiments in magnetic field. Minimal distance between magnet poles is 40 mm.

13. Temperature sensors calibration table.

Additional equipment

1. Sample holder

• Sample rotation by 360° around the windows axis.

• X or XY shift of the sample.

• Asymmetric sample position.

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

2. He-transfer vacuum isolated tube

• Hard connection.

• Flexible connection.

3. Sample rod with a universal flange.

4. Measuring heads, cassette heads.

5. 10-pin electric connections on the top of the sample holder.

6. Helium or nitrogen storage dewar.

7. Dewar transport platform.

Key benefits

• Extremely low cooling agent consumption.

• Flexibility of construction.

• He and N2 operation modes of the system with T-regulator and helium level gauge.