Research Areas / Projects / Facilities / Seminar

 


Instruments & Facilities

He4 cryostats (3 sets)

Home-made standard liquid-helium-pumping-type cryostats. Each one consists of vacuum-shielded nitrogen (outer) and helium (inner) glass dewars. Two of them are equipped with double mu-metal shields. The optimum operation temperature ranges from 1.2 K to 10 K, but operation up to 100 K is possible. One of them can be used with a 7 T superconducting magnet.

 

Dilution fridge (Oxford Instruments; Model AST Minisorb)

Base temperature: continuous:
20 mK
Expected pump switching time of 20-30 minutes
Cooling power:
40 W  at 100 mK
Sample space 37 mm diameter
78 mm
   

 


Dilution fridge (Oxford Instruments; Model Kelvinox)

The system is designed and engineered to make millikelvin temperatures accessible at a low cost to a wider range of researchers. Currently it is equipped with 11 T superconducting magnet. The specifications are as follows.

Base temperature: 50 mK
Continuous flow operation
Cooling power: 20 microwatts at 100 mK
Cool down time from room temperature: less than 6 hours

 


General-purpose thermal evaporator

 

Photolithography facilities

mask aligner (home-made)
photoresist spinner
class 100 ovens (2 sets)
optical microscope (Nikon; Model Optiphoto 66)
photo-stage for producing optical masks

 

Electron-beam lithography system

Consisting of
Raith Model ELPHY QUANTUM beam control
SEM (JEOL Model 5400).

 

Ion-beam deposition and etching system

Consisting of
high vacuum system: base pressure; 1x10-7 Torr
ion gun: (Anatech, 5 cm).

 

Effusion-cell evaporation system

This system is designed to be used for fabricating ultra-pure thin films and, if necessary, cleaning an interface between two successive depositions of thin films using an ion gun. It consists of

ultra-high vacuum system: base pressure 1x10-9 Torr
effusion cells (2 sets)
ion gun.

 

Helium liquefier (Koch Process Systems, Inc.; Model 1410)

Cold box containing heat exchangers, variable speed reciprocating expansion engines, liquid nitrogen precooling system, automatic purification system, Joule-Thomson valve, delivery tube gland and return valve assembly.
One helium compressor (Model 1400)
One 500 liter capacity liquid helium liquefaction dewar.
One helium recovery compressor (Model 50B)
One 300 SCF gas recovery bag.

The liquefaction rate is 12 liters/hour with liquid nitrogen precooling.

 

 

 

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