A high pressure chamber for optical studies at low temperatures

accuracy o f + 0 . 1 0 e . The width of the resonance curve for which it is still possible to measure the shift on the oscilloscope screen should not be more than ~ 1 2 0 Oe. The accuracy in measuring the magnetrostriction constants b y the method described is ~3%. The sensitivity in striction is 10-8.

References

1 2 3

Kotyukov, Yu.N., Brunysheva, A.N. Bulletin of University Departments, USSR Physics 4 (1960) 176 Pettakovskii, G.A., Smokotin, M., Tutova, A.G. FTT 9 (1967) 2324 Smith, A. B. Rev Scilnstr 39 (1968) 378

A high pressure chamber for optical studies at low temperatures V. V. Nefedova and A. P. Minin On the basis of the low temperature chamber described by Itskevich 1 , an optical chamber has been developed for studying semiconductor quantum oscillators in the wave length range from the visible part o f the spectrum to 5/am liquid nitrogen temperature at pressure up to 10 kbar (10 4kN m-2). Fig.1 shows the design o f the chamber which has two optical windows.2 These are 10 m m diameter cylinders, 8 mm high, cut from synthetic sapphire. The cylinder axis is parallel to the sapphire axis. The working aperture of the window is 3 mm. No leak through the windows was observed. A kerosene and oil mixture was used to transmit the pressure and the absorption spectrum of this medium was determined at various temperatures. At room temperature the medium is transparent in the visible region o f the spectrum (90% transmission for a layer o f thickness 0.03 mm) and in the infrared region to 15 Om (from 70 to 37%) with narrow absorption bands in the neighbourhood of 3.45, 6.85, and 7.35 ~um. An additional absorption occurs at liquid nitrogen temperature in the region of 2 to 3.3/am. In some experiments pentane was used as pressure transmitting medium. The chamber was used successfully for working at 77 K with gaseous helium to transmit the pressure, which was measured with a 3 x 4 mm manganin gauge.

.L2,

3,

The effect of pressure up to 10 kbar was studied in the chamber with the kerosene and oil mixture, on the emission spectrum of a GaAs injection laser at liquid nitrogen temperature. The pressure coefficient o f the shift in energy of the maximum emission was determined as dE/dp = 1.15 x 10-5 eV bar-I, which is in good agreement with the value found earlier, dE/dp = 1.10 x 10-5 eV bar-l.3 From this we can conclude that the pressure is transmitted to the specimen hydrostatically. In conclusion the authors thank Academician L.F. Vereshchagin for his constant interest in the work and for fruitful discussion o f the results.

References 26

ltskevich, E.S Prib i Tekh ~7¢sper No 4 (1963) 148 Poulter, T.C. PhysRev 35 (1930) 297 Feinleib, J., Groves,S, Paul, W., Zallen, R. Phys Rev 131 (1963) 2070 The authors are with the Institute of Hklh Pressure Physics, Academy of Sciences, M o s c o w , USSR. Prib i Tekh ~ksper No 6 (1973) 198. Received 29 May 1973.

622

Fig.1 Design of the c h a m b e r 1 -- steel case, 2, 2 4 - nuts, 3, 18 -- plugs, 4 - sapphire w i n d o w s , 5 -- supporting caps, 6 - - connecting nuts, 7 -- intensifier support tube, 8 -- piston producing the pressure, 12 -- rod, transmitting pressure f r o m t h e intensifier, 13 -- manganin gauge, 14 -- specimen, 9 , 10, 15, 16, 17, 19, 2 0 , 21 -- sealing rings, 2 2 -- 2 m m d i a m e t e r electrical lead, 2 3 , 2 6 -- 0.1 m m electrical leads

CRYOGENICS

. OCTOBER

1973