Electromagnetic mass spectrometer

Classified

abstracts

1312-1321

furnace. Water-cooled crucibles of electrolytic copper with maximum heat conductivity are used to minimize fusion of the molten Ti with crucible materials. Heat is supplied centrally by an electric arc and the Ti itself serves as the electrode to avoid contamination. Anon, Machinery

Lloyd, 38, 1966, 36-37.

37 1312. Study of the isotopic disproportionation reaction between light and heavy water using a pulsed molecular beam mass spectrometer. f USA)

Isotopic exchange equilibrium in the disproportionation reaction H,O + D,O -2 HDO was studied at 0°C and 25°C and over a range of deuterium compositions using a pulsed-molecular-beam mass spectrometer. The equilibrium constant k was found to be 3.75 ho.07 at both temperatures. The pulsed-beam mass spectrometer was shown to be effective in minimizing the “memory effect” in the mass spectrometer. J W Pyper et al, J Chem Phys, 46 (6). 15th March

1967, 2253-2257.

42. GLASS,

Development of high thyratrons, and voltage

1313. Vacuum

chambers

for degasifying

metal melts.

(USA)

The vacuum chamber has a downward extending, open end, inlet and outlet pipe connected to the bottom, so that the open end may dip into the melt. A refractory jacket and a conical tapering metal cap, attached to the end of the pipe with packing between, seals against entry of slag. A tube is fixed to the inner face of the cap and extends inward to a distance greater than the thickness of the slag layer on the metal. Dortmund-Horder Huttenunion AG, US Patent 3,314,669, Guz US Parent Office, 837 (3), 18fh April 1967, 864.

Ojficiul

Electromagnetic

ORGANIC

CHEMISTRY,

Synthesis of ammonia on iron, as investigated secondary ion-ion emission. See abstract number

ISOTOPIC

38 by the method

: 18 of

1214.

38 when

1315. Mass-spectrometric isotopic analysis of organic substances ionized by a strong electric field. (USSR)

The design of a field emission ion source which uses a Pt edge and an electrical field intensity of 7 x 10’ V/cm is described. The effect of protonizing was determined by measuring the CXs to Cl2 ratio and found to be negligible. Using this ion source and type MI-1301 mass-spectrometer successful analyses of benzene, pyridine, pyridone, phenol and ethyl ether, were carried out with respect to hydrogen and oxygen isotopes. I Z Korostyshevskiy and I V Gol’denfel’d, Dokl Akad Nuuk SSSR, 172 (6), 21st Feb 1967, 1364-1367 (in Russian). centrifugal

distillation

equipment.

38 (Great

In this apparatus, the distillate is dispersed in film form by centrifugal action. The vapourizer is divided into a series of concentric zones each with a drainage conduit. The condenser consists of a series of trays (one for each zone) which slope downwards with their outer edge positioned over the next succeeding zone, near the inner boundary. Each tray condenses vapour from the associated zone and deposits condensate from its outer edge, with the last tray positioned over a collecting zone. Brit Petroleum Co Ltd, Brit Patent part 6, 10th April 1967, 8.

IV. Materials technology 41. METALS

1,062,032,

and techniques

Patent

Abstr,

7 (14)

used in vacuum

AND ALLOYS 41

Vapour

deposition

number

1254.

of

molybdenum-tungsten

alloys.

See

42 : 31 temperature, gas-filled, ceramic rectifiers, reference tubes. See abstract number 1270.

mass spectrometer.

See abstract

47 : 33 number 1291.

effusion

apparatus

for vapour

pressure

measure-

(US-41

The Bureau of Mines devised and constructed a modified Knudsen effusion apparatus permitting a constant measure of the weight of effusing vapour to determine the equilibrium vapour pressure of metal halides at temperatures up to 1200°K and over the pressure range 1O-5 to lOwe torr. The reliability of the apparatus was established by determining the vapour pressure of potassium chloride. After correcting the partial dimerization of the vapour, data obtained on solid KC1 between 650°K and 950°K can be exnressed bv the equation Pcatm)=7379-(11207/T). A third-law treatment of the-data yields an average heat of sublimation of 53394 kcal/mole. S D Hill et al, Rep BM-R&6849/1966 (Bureau of Mines, Albany, Research

Cenrre) .

GAS

38 1314. Reaction of fluorine with chloromethanes. (USSR) Reactions of fluorine with chloromethanes at .3 to .9 torr were investigated using type Mi-1305 mass-spectrometer and results were confirmed using deuterium instead of hydrogen in the hydrogen fluoride employed. L Yu Rusiu and A E Shilov, Dokl Akud Nauk SSSR, 172 (6), 21st Feb 1967, 1340-1342 (in Russian).

1316. High-vacuum, Britain)

OXIDES

47 1317. A Knudsen

Oreg Metallurgy 38. DISTILLATION, ANALYSIS

AND REFRACTORY

47. OUTGASSING DATA, VAPOUR PRESSURE DATA, GETTERING DATA, RESIDUAL GASES IN VACUUM SYSTEMS, RESIDUAL GAS ANALYSIS 47 : 33 Field ion source for mass spectrometer. See abstract number 1286.

ments. 37

CERAMICS

: 30

abstract

1318. Effect of restrictions to molecular vapourization rate and vapour pressure.

flow upon measurements (USA)

47 of

A steady-state model is employed to calculate the fraction of the vapourizing molecules which ultimately escape when a sample is vapourized in an evacuated tube. The results can be used to correct measurements of vapour pressure and vapourization rate for those vapourizing molecules which re-condense upon the sample after wall collisions. The calculations are also useful in the design bf apparatus. G M Rosenblatt, J Phvs Chem. 71, 1967. 1327-1533. 1319. Surface-induced transitions in highly excited noble-gas ions and quasimetastable peaks in the mass spectra of the noble gases. (USA)

The appearance of some quasimetastable peaks in the mass spectra of the noble gases is shown to be due to a surface-induced transition in which the noble gas atoms lose electrons at a metal surface. These are believed to be transitions of highly excited states of noble-gas ions at the slits of the mass-spectrometer ion source. The states involved are postulated to be the higher Rydberg levels of the ion. Such states, while they may be long lived, are not metastable states. A S Newton et al, J Chem Phys, 46 (5), 1st March 1967, 1779-1787. 1320. Gas extraction from the surface electric field in vacuum. (USSR)

of an insulator

47 in a strong

A device for measuring outgassing of high voltage insulators is described. As the gas extraction from insulators is dependent on the electric field, the measured pressure rise can be modulated by means of interrupting the voltage over the insulator with a frequency of 0.25 c/s. With this method a sensitivity of 2x 1O-8 torr-litreisec can be obtained when the device is pumped by an oil diffusion pump with speed to volume ratio of 0.45 set, and an ultimate pressure of lo-’ torr. Voltages up to 150 kV may be applied and samples may be heated up to 400°C. Outgassing data for steatite ceramics, Teflon, polyvinyl chloride and polymethyl methacrylate at different voltages are given and it is shown that for these insulators the gas extraction is not dependent on the pressure in the range of lo-’ to 10s5 torr. Breakdown voltages were also measured. A A Avdienko and A V Kiselev, Zh Tekh Fiz, 37 (3), March 533-537 (in Russian).

1967,

47 1321. Analysis of the gases released on cleaving muscovite mica in ultrahigh vacuum and of gases which remain adsorbed on the freshly cleaved surface. (Great Britain)

The gases released on cleaving mica specimens in ultrahigh vacuum have been analysed mass spectrometrically and found to consist 429