- . I OFT ORNL P 16|| 3. 47 에 ​hy IT 11.25 11.4 11.6 MICROCOPY RESOLUTION TEST CHART NATIONAL QUREAU OF STANDARDS - 1963 ! S .;;*** ? * Y : . -. . :1.-.. : MK3 : - - of Nu-P-1611 MASTEK Confa 650939-1 OCT65 -- Hi ha THE RESEARCH MATERIALS PROGRAM AT THE OAK RIDGE NATIONAL LABORATORY* LEGAL NOTICE Corominen: This report was prepared u a second of Government sponsored warte Matther than Oudhed e than aprudd or implied, wo mapect to O MOCY- o, ar proom Hacienda tuta monart me not in terting muy.corintenis, ar motion of the talenator comedouroustor thut down -Am, tor the cominado, nor any pero nching and at purata, A. Make my warranty or mor al my tudoration t her sounding from the halal the commentom" mcluding any a . my liabilities wid roapect to the wood, or for dem "wam information. amne, methods or proondaclound the reports e Comunington, or antigua oral contractor popuri, plore of contractor of the countedom, or employee and contract, to the o daramate, or prontam nocte, my hartition part to homeplogut or contract *** As wund ta te whore, spermen uchsa auch eupione or contratar al with the Coumisedon, or we mployment with me contractor. 8. A J. W. Cleland Solid State Division, Oak Ridge National Laboratory Oak Ridge, Tennessee, U.S.A. RELEASED FOR ANNOUNCEMENT - IN NUCLEAR SCIENCE ABSTRACTS ABSTRACT The Research Materials Program of the Oak Ridge National Labora- tory was established to develop the necessary techniques required for the production of ultra-high purity and controlled impurity research specimens (usually single crystal) of immediate and long-range interest to the laboratory. The choice of potential materials has been made on the basis of (a) the gain to a fundamental understanding of solids, and (b) specific requests. These requests have included previously uninves- tigated materials, and varied techniques of purification and crystal growth have been applied to these. The program offers an unusual oppor- tunity to utilize the variety of skills available at a large National Laboratory, and one of the important factors is the coordination of contributions from chemical analysts, crystal growers, and solid state physicists through a Research Materials Information Center. Advances made by improvements in techniques of one group are quickly utilized by the others and analytical services have been changed in certain instances from routine analyses to a continuing program of basic research on a specific material. Examples of initial purification, crystal growth, HIR.. Research sponsored by the U. S. Atomic Energy Commission under contract with Union Carbide Corporation. K .,... - 2 - and final characterization and analysis are presented for (1) molten salt solvent crystal growth studies of Tho,, (2) flcat-zone growth of single crystal grains of vo, up to 5 cm long by 0.5 cm diameter, (3) pre- . purification and Czochralski growth of large (300 gram) single crystals of kci, and (4) modified Stockbarger growth of single crystals of LiF ofi varying isotopic composition. INTRODUCTION It has long been recognized that materials technology of tomorrow is dependent upon an improved understanding of the fundamental properties i n of materials that are currently available, and upon an insight into the thing morgunin potential properties of materials that are not yet available, Progress in understanding the fundamental properties and the ultimate range of properties in many materials has been severely limited in the past by a. lack of specimens of sufficiently high purity and crystalline perfection and the use of single crystals is required in many experiments to char- acterize unambiguously many physical phenomena. The Research Materials Progre.m of the Solid State Division of the Oak Ridge National Laboratory was established in 1961 to develop the nec- essary techniques as required for the growth of research specimens, (usually single crystal) of ultra-high purity and controlled impurity: The choice of potential materials for consideration has been made, for WAS TULETT. 2. m. RETRI PELANLAR .. . A the most part, on the basis of the potential gain to a fundamental under-, standing of solids that may result from an intensive investigation of a given material by a number of research groups, and on the basis of an expressed need for a specific research material. These requests have included certain materials that have not been investigated in the past, .. .. 3 - and varied techniques of purification and crystal growth have been applied to these new materials. No attempt has been made to duplicate any effort on materials of commercial interest, such as Ge and Si, since specimens of good quality can usually be obtained from industrial laboratories. The entire program involves a number of research divisions at the . Oak Ridge National Laboratory. The Analytical Chemistry Division has pro- vided a variety of analytical techniques, and a major portion of the actual work toward crystal growth has been conducted by research groups within the Metals and Ceramics, Reactor Chemistry, and Solid State Divisions of the Laboratory. These groups have also conducted a variety of physical prop- erty measurements, and selected samples have been supplied to other re- search groups within and without the laboratory for cooperative measure- ments that have aided in specimen characterization. External research organizations having superior equipment or experience in handling a desired material have also been called upon to produce a particular material on occasion. Information concerning the availability of and need for high purity research specimens has always been difficult to obtain, and the purity, size, dislocation content, and other physical properties of existing ma- terials are constantly being altered or improved. A Research Materials Information Center was therefore established in 1963 as a part of the Re- search Materials Program to collect and provide information on the purifi-. cation, growth, final characterization, and availability of research quality materials to both producers and users. The ready availability of an accu- rate up-to-date listing of research materials has served to eliminate a large amount of duplication of effort by individual research groups in ...................................... **** v ero - 4- producing materials that were already available elsewhere. The simultan- eous listing of desired materials has served to focus the attention of researchers on new avenues of investigation. Perhaps the most important technical accomplishment of the Research Materials Program and the Research Materials Information Center has been that of an enhanced cooperation between analytical chemists, neutron acti- . . . vation specialists, mass spectrographers, crystal growers, and crystal property researchers as regards a continuing exchange of information on improved materia] 3. Any improvement in the techniques of one group is. reflected in the subsequent data and analyses of the other groups. Ana- lytical techniques have been changed in certain instances from that of routine analysis to that of a continuing program of basic research on a specific material. The presence of unexpected impurities, or the pro- nounced effect of certain impurities has sometimes only been revealed by using a wide variety of analytical techniques, or of procedures in crystal growth, or of physical property measurements. It must be emphasized that close cooperation is required between those who analyse, grow, characterize, use, and receive or provide inform mation on research materials, and this cooperation must transcend any individual division, laboratory, university, private company, or govern- X ment agency. A wide variety of materials is currently under investigation in the Research Materials Program, and varying degrees of success have been achieved with each specific material. It is not possible to discuss each material in general; hence, examples of initial purification, crystal growth, and final characterization and analysis are presented for (1) molten salt solvent crystal growth studies of Thon, (2) float-zone growth - 5 - of single grains of Uo, up to 5 cm long by 0.5 cm diameter, (3) pre- purification and Czochralski growth of large (300 gram) single crystals of kc, and (4) modified Stockbarger growth of single crystals of LiF of varying isotopic composition. (1) Molten Salt Solvent Crystal Growth Studies* Molten salt solution techniques have been employed to produce rare earth germano-molybdates, rare earth germano-tungstates, thorium dioxide, beryllium oxide, trivalent and tetravalent metal silicates, and to exam- ine the phase transformation of thorium silicate from tetragonal (thorite) to monoclinic (huttonite). Hydrothermal techniques, using water, ammonia, and ammonium sulfide as supercritical solvents, have also been used for crystal growth. Favorable growth conditions have been explored in water systems for Mgo, Beo, Thos, Tion, and ferrites. Ammonia systems have been explored as a solvent for nitrides, and ammonium sulfide has been used to examine the best growth conditions for HgS, Hg,S, cas, Zns, and US,. The highest growth rate for single crystal ferrites has been achieved with a 0.5 N lithium hydroxide solution at 500°C and 30,000 psi. One can re- place any fraction of the divalent ion of a pure ferrite with another divalent ion, anċ the presence of zinc or manganese has enhanced the growth rate in these ferrites. Quartz has been grown at 15,000 psi and 410°C from 0.5 M KOH in a graphite crucible with a stainless steel liner and this crystal (about 1 cm on an eage) has been used in electron spi. resonance studies. Commercially grown quartz is contaminated with sili- con, which complicates the interpretation of ESR data. "G. W. Clark and C. B. Finch, Metals and Ceramics Division, ORNL: -- pe : 1711. ........MAYIN LATIN PV X = Single crystals of thorium dioxide have been grown from a molten lithium ditungstate solvent. Figure 1 is a sectional view of the appa- ratus as employed. Growth occurred primarily by solution transfer from the Tho, nutrient at 1250-1350°C to the thoria seeds in a cooler region, as indicated by the temperature profile, and an increased growth rate was obtained by adding 2 mole % B20, to the solvent. Figure 2 is a photo- graph of a typical crystal, an optically transparent octahedra, about 3 min on an edge. These crystals contain less than 500 ppm W and less than 50 ppm Ii as major impurities, and the same technique has also been employed to produce Tho, crystals containing 200 to 1000 ppm of several trivalent : lanthanide ions for studies involving paramagnetic resonance of ga3* and electron spin resonance measurements of crystals as doped with ga, Dy, Er, and Yb. Nd-doped crystals are currently being grown, and Ce, U, and Cm doped crystals are anticipated. (2) Float-zone Growth of Single Crystal Grains of UO* Uranium dioxide single crystals have previously been grown by vapor transport, in molten salts, and by arc melting. Recently a floating-zone technique* has been used to produce large (1 cm by 5 cm) nearly stoichio- single crystals of uog. The method is that of inductive heating of an isostatically pressed and hyárogen-sintered polycrystalline rod as is indicated in Fig. 3. The semiconducting nature of vo, is such that the central region becomes molten while the surface remains as a solid skin or crucible. Figure 4 is a photograph of a cross section of a zone melted rod, containing a single crystal. Zone melting as a technique for growing single crystals of vo, is attractive in that one can produce large crystals, external contamination "G. W. Clark and A. T. Chapman, Metals and Ceramics Division, ORNL.C - 7.- is reduced, evaporation-condensation tends to purify the crystal, and the material economy is good so that the growth of enriched vo, crystals seems practical. It is also anticipated that this growth technique can be extended to additional refractory oxides for which other methods of growing large crystals have only been moderately successful. (3) Pre-purification* and Czochralski Growth** of Single Crystals of Kci. The most sustained effort in the Research Materials Program to date has gone into the preparation of single crystals of KCl of high purity and perfection. One of the many reasons for this work is indicated by Fig. 5, which is a graph of the optical absorption coefficient vs dose of co photons and indicates the apparent rate of growth of the F-center concentration for crystals as produced in various laboratories. It is evi- dent that data of this type is of little value in studying F-center pro- duction since it has also been demonstrated that successive crystals from the same producer show this same type of variation in apparent radiation sensitivity. The normal approach to purification can either be that of chemical techniques, or of some physical process such as zone refining. The ideal approach would be that of utilizing both techniques to the limit; however, such may be prohibitively experisive of both time and effort. The approach for kcl to date has been primarily chemical in nature. Reagent grade *R. B. Quincy Ana D. E. LaValle, Analytical Chemistry Division, ORNE'- **C. I. Butler and J. R. Russell, Solid State Division, ORNL.. - 8 starting materialº is recrystallized, redissolved, and extracted with a solution of thenoyl-triflouro-acetone (TTA) in 4-methyl-2 penatone (hexone). The KCI is recovered by crystallization, dried, and I used in a quartz fil- tration tube. A mixture of chlorine and hydrogen chloride gas is passed through the melt, which is finally filtered and collected as a pre- packaged starting charge for crystal growth. The total impurity content at this point is about 25 ppm. Extreme care is used in transferring the starting charge to the growth crucible in a glove box, and the purification and growth apparatus are kept in a semi-clean, dust-free room with humidity control. Crystals are grown by the Czochralski technique of pulling a seed crystal from the melt in a platinum crucible, and additional purification is obtained by impurity segregation during growth. The entire growth process is con- ducted in a chlorine-hydrogen chloride atmosphere to eliminate water, hydroxyl ions, and to further reduce the Brand I content. Figure 6 is a photograph of a typical crystal, which is 10 to 15 cm in cross sectional area, and 200 to 250 grams in weight. On occasion crystals exceeding 300 grams have been grown for special experiments. The final product has been extensively analyzed for as many as 40 elemental and anionic radicals. Figure 7 is a bar graph of the aver- age major impurity concentration in ug/8 for crystals grown in 1964, as compared to commercial crystals; Figure 8 is a bar graph of the same data as plotted against the logarithm of the average major impurity con- centration in ug/g. Figure 9 indicates the limit of detection in parts per billion for some of the important elements that may be present as im- purities in these crystals. Those elements in parentheses are estimated -9. values for the particular method, and some of the wide variety of methods employed in the analyses are indicated. This data serves to indicate the type of cooperation that has existed between the crystal grower and the analysts for this one material, and the lower limit of detection for several elements has been reduced to as much as one-twentieth of the pre- vious values by this cooperative technique. Possession of such ultra-pure starting materials and controlled crystal growth techniques has permitted quantitative experiments on crys- tal doping. Figure 10, which is a graph of the optical absorption coeffi- cient for F-center concentration (corrected for M-band absorption) versus the energy absorbed from co photons, indicates the extreme sensitivity of the rate of growth of the F-center concentration as a function of the concentration of lead impurity atoms in ppm. A linear : relationship be- tween the optical absorption coefficient and the concentration of lead in a special series of crystals has been demonstrated' by experiments of this type, and this analytical technique is sensitive to an impurity content of 50 ppb or even lower. This method is far less time consuming and expensive than the conventional methods of atomic absorption spectroscopy. Work of this nature has been extended to include the effect of doping with other impurities such as Sr and Ca, the effect of impurities on hardening, col- oration and annealing, light scattering and luminescence experiments, and the effect of plastic deformation on the colorability of pure and doped crystals. An entire research program has developed's and has permitted a better understanding of a variety of solid state processes. It is obvious that experiments of this nature could not have been conducted on the type of material that was indicated in Fig. 5. - 10 - (4) Modified Stockbarger Growth of Single Crystals of Lif A similar program of comparable magnitude to that on KCl has also been conducted in an effort to develop the techniques and apparatus as required for the production of single crystals of Lif with selected ratios of the lithium isotopes. Lithium fluoride is of interest because it transmits further in the ultraviolet region than any other known solid state material, its dispersion in the visible spectrum is low, it has a higher dispersion power in the infrared than either NaCl or Cafy, and the cubic symmetry, stability in air, hardness and resistance to discoloration with use have made it of great value in ultraviolet and infrared spectros- copy. It can be used in conjunction with quartz to make achromatic and apochromatic lenses for ultraviolet work, and its high transmission in the vacuum ultraviolet range makes it suitable for use in Cerenkov counters. Lithium fluoride can be grown from the melt in unusually perfect condition, can be cleaved with negligible distortion, and is easily etched. These properties have permitted studies of dislocation origin, movement, and multiplication. Many of the physical properties of LiF, such as thermal conductivity, refractive index, infrared absorption and reflection, unit cell size, and neutron absorption cross section depend on the isotopic content. The starting material in these studies is high purity Lion, with about 200 ppm Ca, K, Mg, and Na as the major impurities. This material is dissolved in distilled water, de-ionized, dehydrated with HF, and then HF “R. E. Thoma, C. F. Weaver, and R. G. Ross, Reactor Chemistry Division, IN ORNL. - ll - treated at 900°C with an anhydrous HF plus H, mixture. Most of the re- maining impurities are reduced and precipitated as fine particles, which settle out of the melt, and hand-picking of colorless and speck-free material in a vacuum dry box gives an end yield of about 65% of the start- ing material. The major impurity concentration at this point is about 100 ppm Ca and less than 50 ppm Na. The hand-picked charge is loaded in- to a H, fired nickel crucible in a vacuum dry box, which is then sealed, i:serted into the Stockbarger furnace, and evacuated. Figure ll is a schematic drawing of the furnace as employed for crystal growth. The temperature-'is controlled at the melting point (848°c) within 0.2°C, and the equipment is generally unattended during the 3-week period required for growth and anneal. A quartz window permits direct ob- servation during distillation, bubble formation, or interface formation CU in polycrystalline ingots such that corrective action, that may include starting again, can be taken whenever required. The typical drive rate is 1/2 mm per hour, and crystals are grown in a partial vacuum, or under MOWO a protective pressure of He gas. Figure 12 is a photograph of the entire apparatus as assembled; Fig. 13 is a photograph of a typical crystal that weighs 278 grams and contains 98.06 at. % 'Li. Crystals of isotopic LiF ranging from 50 to 99.99% 'Li and weighing 200 to 400 grams have been produced, and selected portions of these crystals have been used for the development of new spectroscopic standards for LiF, for neutron scattering experiments, for use in developing a thermal neutron activation analysis method for deter- mination of oxygen in the ppm range, and for ultraviolet, infrared, x-ray diffraction, and light scattering studies. The total divalent cation con- tamination content of some of these crystals is less than 30 ppb. - 12 - The variation of the thermal conductivity with the isotope effect iw larger in LiF than in any other alkali halide or Ge. P. D. Thacher and R. O. Pohl of Cornell University have used selected portions of these crystals, and have also grown crystals by the Czochralski technique from nighly purified starting materials, as supplied by the Research Materials Program. Figure 14 is a log-log plot of the thermal conductivity K in watts/cm deg vs the absolute temperature in °K for chemically pure crys- tals of Lif of different isotopic concentration, as measured by Thacher and Pohl. The maximum values indicate that LiF is better than solid He as a phonon conductor, and the maximum values approach the theoretical value for phonon conduction in this material. Figure 14 indicates the -- extreme sensitivity of the thermal conductivity to isotopic doping. Very similar curves have been obtained as a function of impurity content - - - - - OV (Fig. 15) and molecular impurity content (Fig. 16); hence, it is manda- tory that the impurity contert be reduced as much as possible before one can utilize the isotopic effect to examine phonon scattering. These same crystals have also been used to study phonon scattering by crystal surfaces. This so-called boundary effect can be studied over a wider temperature range in LiF than in any other alkali halide. The isotope effect and the boundary effect give rise to the only two phonon scattering rates that are reliably known, hence, investigation of both rates in the same crystal has made a test of the theory more definite. Elimination of the impurity effect has permitted a study of the thermal conductivity as a function of crystal size, and of cleaved vs sard- blasted surfaces. It is anticipated that future studies will be made of phonon scattering by structural defects, such as dislocations or by ir- radiation, now that the problem of impurity content has been solved. - 13 - There are several materials for which purification or growth methods have not proved successful to date. An example is that of vapor phase growth of stable (hexagonal) cinnabar single crystals of Hgs. The problem is that the crystals deposit in a cubic meta-cinnabar form at a temperature as low as 290°C, with a subsequent phase change (that destroys the crystal) below that temperature to the hexagonal cinnabar form. There is little if any effect of pressure up to 10 atmospheres on the tempera- ture of the phase change; hence, it is anticipated that one must vapor deposit below 290°C, or consider hydrothermal techniques using supercriti- cal solvents to obtain stable (hexagonal) cinnabar single crystals of Hgs. Another example of the lack of success is encountered in the case of single crystals of MgO of good quality and high purity. The most ef- fective method of crystal growth of Mgo to date is evidently that of fusion between high current carbon electrodes, with a slow cooling of the resultant mass of molten material. This technique, however, requires a blanket of MgO powder for thermal insulation during the cooling process; hence, the initial charge of calcined or pelletized Mgo must be at least 25 lbs of material. Mgo has been purified by an ion exchange technique down to 100 ppm Si, 100 ppm Al, and 50 ppm of the transition elements; however, the puririca he purification process is far too expensive to consider the production of 25 lbs of starting material. The main purpose of the Research Materials Information Center“ is to provide, on request, information about the availability of high purity inorganic research materials, such as metals, alloys, semicon- ductors, refractory or insulating compounds, lasers, and optical and "T. F. Connolly, Solid State Division, ORNL. . . 14 - magnetic materials. Aside from a "visible" file which provides for a rough anå ready listing for telephone requests, the main collection con- sists of data sheets, abstracts, reports, and papers that have been coded as to material, form, dimensions, orientation, impurity content, method of crystal growth, final analyses, specific properties, and intended use. from a thesaurus of more than 400 coding terms. The data sheet, abstract or document page, along with the appropriate code bits, are photographed and stored on a 100 It reel of 16 mm microfilm, as indicated in Fig. 17, and each reel (cartridge) can be searched by punching out any of the coding terms on the keyboard (Fig. 18). The machine will search about 2000 pages, or one cartridge, in about 15 seconds, and one of the greatest ms advantages of this storage and retrieval system is that the document or data sheet can be scanned for information or one can obtain an immediate photocopy if necessary. The present collection consists of about 1400 data sheets on available materials, and about 14,000 abstracts and docu- ments as stored in 45 cartridges. In conclusion, it is evident that the present situation on research in materials is such that one can no longer conduct a meaningful experi- ment on just any specimen without knowing its purity and perfection. A major portion of the success with KCl and Lif has been as a result of a constant interchange of materials and data between the crystal grower and those who have employed a wide variety of analytical techniques, and it is anticipated that a central "storehouse" or "exchange" of Information, standard samples, and comparative analyses will be required to improve the quality of many research materials in the future. 1 FIGURE CAPTIONS Apparatus for growth of Tho, single crystals. Single crystal of Tho. Schematic diagram of equipment for zone-melting UO, zone melted vo, rod containing 5 cm single crystal. F-center coloring curves for kci prepared in different . Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 ' - . - - - laboratories. Fig. 6 Single crystal of KC1. Fig. 7 Bar graph of major impurity concentration of KCl. Fig. 8 Logarithmic bar graph of average impurity concentration of kci. Fig. 9 Method of analysis and limit of detection of impurities in kcl. Fig. 10 F-center coloring curves for kcl crystals doped with lead. Fig. 11 Apparatus for growth of Lif single crystals. Fig. 12 Modified Stockbarger furnace assembly for Lif. Fig. 13 Single crystal of LiF. Fig. 14 Isotopic effect on thermal conductivity in LiF. Fig. 15 Comparison of isotopic and impurity effect on thermal conduc- tivity in LiF. Fig. 16 Molecular impurity effect on thermal conductivity in LiF. Fig. 17 Information coding bits and document storage on microfilm. Fig. 18 Recordak Miracode retriever and Lodestar Reader-Printer. ...... .. ..... REFERENCES = i oi 1. R. A. Weeks and M. M. Abraham, J. Chem. Phys. 42, 68 (1965). 2. C. B. Finch and G. W. Clark, J. Appl. Phys. 36, 2143 (1965). M. M. Abraham et al., Phys. Rev. 137, 138 (1965); M. M. Abraham, E. J. Lee, ánä R. A. Weeks, to be published in J. Phys. Chem. Solids. 4. A. T. Chapman and G. W. Clark, J. Am. Ceram. Soc., Sept.,. 1965. 5. W. A. Sibley and E. Sonder, Phys. Rev. 128, 540 (1962). 6. R. B. Quincy and D. E. LáValle, "High Purity Potassium Chloride," ORNL-IM 1071, March, 1965. 7. W. A. Sibley, E. Sonder, and C. T. Butler, Phys. Rev. 136, A537 (1964). 8. C. A. Plint and W. A. Sibley, J. Phys. Chem. Solids 42, 1378 (1965); F. Felix et al., Quartalbericht Oct.-Dec. 1964, EURATOM-Vertrag No. 028-64-1 TEE (R&D); W. A. Sibley and J. R. Russell, J. Appl. Phys. 36, 810 (1965). 9. P. D. Thacher, thesis, Cornell University, Report. No. 369.. ORNL-DWG 64-9622 PI THEROCOUPLE WELL REFRACTORY PLEAD Pt COVER PA RESISTOR ON 3 Al2O3 CORE- wwwwwwwwwwww ThO2 SEEDS - PI LEAD CRYSTALLIZATION ZONE WWWWWWWWWWWWWWWWWWWWWWW TO CONSTANT VOLTAGE POWER SUPPLY - 24 MESH PE GAUZE BAFFLES -ThO2-SATURATED (11.3 mole %) Li20.2 W03 SOLUTION Pf LEAD 3-4 cm - - SUITE. MITOI ΛΛΛΛΛΛΛΛΛΛΛΛΛΛΗ -ThO2 NUTRIENT PELLETS 3 cm PA LEAD -Pt CONTAINER 1225 1275 1325 TEMPERATURE (°C) IN THER- MOCOUPLE WELL DURING TYPICAL GROWTH CONDITIONS 7 NICHROME AUXILIARY RESISTOR *** Apparatus for Growth of ThO2 Single Crystals from Li20.2 W03 or Li20.2W03-2 mole % B203 Solvent in Air. Sectional View. - .. . .. ots... . PHOTO 80293 - On.am . . .' 1 2 " . . * - . mm . Octahedral Tho, Single Crystal Grown from Li,O ?wo, Solvent at 1280°C. ܂ . . . . . . . . ' : ; ܝܙ ܕ ܕ ܝܫܠܘܗ ܟ . ܫܫ ܙ . . ܫܫܙܚ ܫܝܫ ORNL-LR-DWG 67057 200 ABSORPTION COEFFICIENT (cm') Mo 0 0.2 0.4 O 5 10 GAMMA DOSE (r) 15 (x10?) in the more time that moeite wat eressio t med in 'simmans eithio d - - - ." . : " " ! انا ح و . . *و .. 4 . ه ب - - - ----سس -- مد - 4. - ۰۲ : مديد ميهم .. م ... نننننننتند دهم ین نشستنضمنة .. ما ممکعت ن میشدم ...... : حد سموه نه شو. د م لمسهسننننمننننمهتنعسعسضنها .- - - - - . .. - - -- - - ... - - . --- .. . . .. . -- eneratoriniai terc tatertai n ing the entire consistente de tratamente AVERAGE CONCENTRATION, ug/s W bolji IN OH ORNL Major impurities in ORN DID UURINN IIIIIIII VUUNI Na TYPE OF IMPURITY commercial 'which were grown during 1964 * The bars show the average impurity concentration for crystals P TUNI TOI IIIIIII Br DAONIO IIIUNI UONOIDI NUMUI to 110-> and Commercial KCI Single Crystals RD I Major impurities in ORNL* and Commercial KCI Single Crystals for crystals * The bars show the average impurity concentration grown during 1964 . WORNL mercial z • 50- w G WP AVERAGE CONCENTRATION, SC, 24 XX OM · Rb IMPURITY ORNL DWG. 55-7625 Method Limit of Detection (ppb) Atomic Absorp. Spec. Pb Flame Phot. Emiss. Spec. Wet Chem. Neut. Act. Anal. Ag Mass Spec. Lum. 100-1000 Absorp. Spectro- photom. (BO2) : Al Са Pt Mg1 NO3 PO4 As (02) (OCN) Ni Rb Pt SO4 Mg Si B 10-100 Fe (Cu) co z (Ag) (Cu) (Sn) 1-10 Be Mn Pb OH Pb (TI) ORNL-DWG 64-1811R o PURE 0.5 ppm a's, CORRECTED ABSORPTION COEFFICIENT (cm-19 -- - - - -- GAMMA IRRADIATED -6 ppm 60 ppm o 5 . . 10 . 15 20 25 ENERGY ABSORBED (Mev/cm3) 30 (x 1015, QUARTZ WINDOW ORNL-LR-DWG 65683A -2-in. GATE VALVE TO VACUUM HEADER DISCHARGE VACUUM GAGE TO VACUUM HEADER - TEFLON PACKING VACUUM PRESSURE REGULATOR HELIUM BLANKET VENT CV! COOLING H20- HYDROGEN SUPPLY NICKEL FURNACE LINER HELIUM SUPPLY -0.010-in. SILVER REFLECTOR THERMOCOUPLE WELL -43/4-in. INSULATION BRICK Blue ACTIVATED CHARCOAL COLD TRAP NICKEL CRUCIBLE -TWIST LOCK CONNECTOR MARSHALL FURNACE - -THERMOCOUPLE WELL HELIUM BLANKET HELIUM BLANKET_VAL T EFLON PACKING COOLING H20 K-SHAFT FROM DRIVE MECHANISM IN -TEFLON PACKING COOLIN - SHAFT FROM DRIVE MECHANISM Lif Crystal Growing Apparatus. mense met sy hart with man, may page .ند 5 1. . مه سعهعتتحدس . د والي - ا - . - . . . " • . . ا متنعته . .. . محمد .. .. .. ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . محسن مسلمكمانسيعملندمدت .* :. .: منه . - ۲ : : : : : : - 1 , فر 2 رن فر ا : نم . م . . . . . . . 1 10 ار .. ه مه نه .. ... " . . = ا : : "" . * نصة مهمة ::۰۰ - -- . ** ا و له . : : . . ل . . . . . . -ه .. همه . ... . .. . . .. . . . . ... ... . ... مسه .. .. . ستستمنيتشمت سر . - - . - . . - - وعد - ه = = . ب = اسم . - . - - *- " ا" : ممددمنوشنه.ین. ..،.،،نه مشتمم نیست.مهم ..... YA III . - . . د هه ۰۲۰: مجم. سعی و سمت GLASS 631:18: 1. (۰ 1 ۲۸۹ سسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسسستنلمسسسمه ۲ : ... . . .. .. .. ... ,ممه . ... . . .-۰۰ ا ا ا ا . | | | . - ا - . . . . . ا . - . - . - . - . - + می ده انسیسیدنم ... ، مممممممممممممم . . نعمه ....... . .. . . ... . . . . .. م م ما م. . . .. . . .. ... ... . . . . .. هما از .و نقتدينه . . . . خسته . . . به مقدسنسننه قمیضه د ننتنممنننشسته کمسن همینه بیانیه س ندیست . . . و ... کننده Jr TY Na 11 . : .. .. . . 2001 2004 1001 (8) eta - THERMAL CONDUCTIVITY IN WATTS CM-' DEGREE %7Li in LiF. crystal size (A) 99.99 7.55x6.97mm (B) 972 5.58x5.10mm (C) 92.6 5.77x5.14mm (D) 50.8 5.06x5.00mm 0.14 I EMPERATURE io 20_ TEMPERATURE IN DEGREES KELVIN 50-100 * 100 THERMAL CONDUCTIVITY IN WATTS cm' DEGREE! (A)97.2%7Li in LiF (B)99.99 % 72 i + IMPURITIES in Lif į o o so oo TEMPERATURE IN DEGREES KELVIN -q -* 1 ' 50 THERMAL CONDUCTIVITY IN WATTS cm-' DEGREE! (A) HARSHAW LIF (B) HARSHAW LIF REGROWN (C) HARSHAW LIF REGROWN CONTAINING OH 0. 01 5 10 20 TEMPERATURE IN DEGREES KELVIN 50 ido . . . AC . TITV . . . R سميننعسنممممممممممن سمنة لتسمممنننمنت “.... .. mon/ www. 口口口口口​|-- 1口口口口​| 口口口口口口- ​口口口口口​| =口口口口 ​1 - tball - -No . 1 مشششضضضضشسشسسسحتهمس 4.144** * ا ع : جدا ::: 1 : : : ، م : : د | = * * * : : + و ار . : م م م م - - مستسهمیه مسلم. نهم:ة - - - معه + - م . ..هد ..... . .. ........ .. . مده ..سوننه . . .. . .... ج۲۹/ '.- م . * . ه . - " . . . - - . . . . . . . ع - - . . . .. . . .. .. . . . - .. شا . . . عده - سر کی A در همه - :: اقامها . م 3 2 : 42 جبکہ تمام .ا - . --- د.سه حساسهممم يم.. مدة د. ممد سه م مه ده د مسدد سه۰۰۰ . . ...mmm.. END DATE FILMED 11 0/65