.1 1 boy WW. h *AH W . JINA NI ! ! M MAXIMA WIN ALA '1 ' ile W ..A wit . Al SW Me ) INI 11 UNCLASSIFIED ORNL 87 BRN1-7-89 2.216 CON*812 - JUL 15 1954 MASTE: A LOW TEMPERATURE LIQUID INFRARED ABSORPTION CELL* 3 by 8. W. Morgan, P. A. Staats, and R. G. Steinhardt** Physics Division, cax Ridge National Laboratory Oak Ridge, Tennessee The physical characteristics of infrared trans- parent materials have made difficult the design and con- struction of liquid or gas absorption cells which remain vacuum tight when cycled over a large temperature range. A rather complex liquid cel for low temperatures was described by Holden et al., while simpler cells have been . used by McMahon et al., ? and Ewing.3 Each of these cells has had some disadvantage in complexity, in sample volume, or in versatility. merge wow m rusy, c cute, we do Cout . Am A. X wcb wamegee or otructor al imwly wed metus; e ancomatos, e pronto secen lo. may wieruston pul Ao woh the bove, porno ista ualian, art , or woonploynal viu euch contractor. .mywarty or mo Court , white, or .. my llenos vid moepoet to the wood or lor d al may karakter, aparatas, method of process decland to the report wy hot lattiat The most womapund um socont of Corona uincter of the conclusion, of employed wel corotor, to do adent that lown, or washine of the lordon calendo report, or that u tou, empre the Canadian, mr M NPM Motha bola de Comandos: cu p caclos hall of the Contou" including e , or where once contractor primeru, wo wploys de report. ar leurs no report to do my- routing from the ored wort. Notdoor the United or contract mo was - LEGAL NOTICE - i - - 12 A low temperature liquid cell has been constructed Į by modification of the conventional sealeä infrared cell. It has been repeatedly cycled through the range 3000 - 77°K, and by the use of various liquids at their boiling or freezing points has been maintained at fixed inter- mediate temperatures for extended periods. The liquid cell is formed by a gold foil spacer pressed between two circular windows. The windows must have some plasticity to make a vacuum-tight seal. CsBr is normally used, though Arce works satisfactorily and is less subject to chemical' attack. The cell is sealed by pressure applied through a specially designed ring, as shown in Fig. 1. Pressure is applied through eight bolts distributed around the perimeter, which are tightened until the ring shows a slight deformation. Two small pieces of gold foil placed near the center of the sample area minimize changes in cell thickness as the window deforms slightly under pressure. The sample area has a maximum aperture of 1", which may be reduced by the design of the spacer. . '..! - . , - E - "L i si w wie * Research sponsored by the U. s. sitomic Energy Commis- sion under contract with the Union Carbide Corpora- tion. Frie < - - i. Chemistry Department, Hollins College, Hollins College, Virginia. ! - ETUSKIRT NOT FOR PUBLIC RELEASE ONNICIAL LISTRIBUTION MAY BE MADE OFFICIAL QUESTS WAY BE FILLED. REPORT ALATAIMS NOTHING OF, PATENT INTERESL FROCEDURES ON EILE IN RECEIVINO SLCJION. doi - COOLANT SAMPLE ACCESS RING - GOLD SPACER WINDOWS > INDIUM GASKETS Fig. 1. Detail of Low Temperature Cell. Access to the sample volume is provided by two 1/32" 1.d. stainless steel tubes connected to valves outside the Vacuum jacket. A vacuum-tight seal of the access lines to the cell is made by an Indium gasket. The cell is cooled by conduction, the housing being a part of the base of a thin-walled stainless steel Dewar. The Dewar mounts in a vacuum jacket with two infrared transmitting windows. To minimize radiation 1068 and to prevent corrosion, all parts of the cell other than windows and stainless steel are gold plated. coupled to the gas supply and the second to a vacuum Hne. After evacuation of the cell and vacuum jacket, the Dewer is cooled to the temperature at which the gas will liquify, and the sample 18 admitted into the cell. . - . . . . : When the liquid dcvel has pasocd the top of the samplo area, the access line 18 scaled and the spectrum taken. 'The sample can usually be removed by applying vacuum to the accc68 tubing, and the cell immediately checked if necessary for window bands. In using liquido, the sample 18 placed in the cell by suction or pressure, nt room temperature, and the Dewar then coolcdu * * · ** - - .. . : - . . . .' - - E -- The cell operated reliably, and 10 simple to assemble and disa68cmble for clcaning or modification. Spectra have been recorded or liquid methane, othane, and other hydrocarbons, as well as liquid BF7 and solutions or RF7 in liquid Xe. These spectra will be discussed briefly.' LITURG URE REFERENCES 1. Holden, Taylor, and Johnston, J. Opt. Soc. Am., 40, 757 (1950). 2. McMahon, Hainer, and King, J. Opt. Soc. Am., 32, 786 (1949). 3. Ewing, J. Chem. Phys., 2 2250 (1962). . -* . . E S S . ! i 1 . " ! " .2 B . . . . DATE FILMED 12/31/164 UA M . TL u . . . ti . - 2 AY ... B nime . IH . V4 LEGAL NOTICE . NINO r . . . 2 . WA - This report was prepared as an account of Government sponsored work. Neither the United Statos, nor the Commission, nor any person acting on behalf of the Commission: A. Makes any warranty or representation, expressed or inplied, with respect to the accu- racy, completeness, or usefulness of the information containod in this roport, or that the use of any information, apparatus, method, or process disclosed in this report may not infringe privately owned rights; or B. Assumos any liabilities with respect to the use of, or for damages resulting from the use of any information, apparatis, inethod, or process disclosed in this report. As used in the above, "person acting on behalf of the Commission” includes any om- ployee or contractor of the Commission, or employee of such contractor, to the extent that such employee or contractor of the Commission, or employee of such contractor prepares, disseminates, or provides access to any information pursuant to his employment or contract with the Commission, or his enuployment with such contractor. IN 0 D . ' . * 16 405 ir. . . ABELS Lt. 11 71 LA . . . WV TA 27 END 12 TIL 13 MY