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Measurement of Parity Nonconservation and an Anapole Moment in Cesium

The amplitude of the parity-nonconserving transition between the 6S and 7S states of cesium was precisely measured with the use of a spin-polarized atomic beam. This measurement gives Im(E1pnc)/beta = -1.5935(56) millivolts per centimeter and provides an improved test of the standard model at low energy, including a value for the S parameter of -1.3(3)exp (11)theory. The nuclear spin-dependent contribution was 0.077(11) millivolts per centimeter; this contribution is a manifestation of parity violation in atomic nuclei and is a measurement of the long-sought anapole moment.

Journal Article↗

Base composition of deoxyribonucleic acid of sulfate-reducing bacteria deduced from buoyant density measurements in cesium chloride.

Saunders, Grady F. (University of Illinois, Urbana), L. Leon Campbell, and John R. Postgate. Base composition of deoxyribonucleic acid of sulfate-reducing bacteria deduced from buoyant density measurements in cesium chloride. J. Bacteriol. 87:1073-1078. 1964.-The base composition of the deoxyribonucleic acid (DNA) of sulfate-reducing bacteria was calculated from buoyant density measurements in CsCl. The sporulating sulfate-reducing bacteria fell into two groups: Desulfovibrio orientis with a DNA base composition of 42% guanine plus cytosine (G + C), and Clostridium nigrificans with a DNA base composition of 45% G + C. The mesophilic relative of C. nigrificans had a DNA base composition of 46% G + C. Thirty strains of nonsporulating sulfate-reducing bacteria called D. desulfuricans were studied. They fell into three groups as judged by DNA base composition: group I (11 strains), 60 to 62% G + C; group II (13 strains), 54 to 56% G + C; and group III (6 strains), 46 to 47% G + C. These data underline the need for a taxonomic revision of this group of microorganisms.

Bacteria↗

Buoyant density of the hepatitis A virus-like particle in cesium chloride.

We recently visualized by immune electron microscopy a virus-like particle in the stools of patients with hepatitis A. The particle measured approximately 27 nm in diameter and morphologically resembled a picornavirus or parvovirus. To further characterize this particle, we have determined its buoyant density in cesium chloride (CsCl) by ultracentrifugation. Hepatitis A particles from three positive stool specimens were isopycnically banded in separate experiments, and the gradient fractions were examined for particles by immune electron microscopy by using hepatitis A convalescent sera. In each experiment, the particles were observed in a normal distribution about a peak fraction with a mean density of approximately 1.4 g/cm(3). The buoyant density of 1.4 g/cm(3) in CsCl together with its morphology and the reported resistance of hepatitis virus to acid, ether, and heat suggest that this particle is parvovirus-like.

Centrifugation, Density Gradient↗

Degenerated optical parametric chirped-pulse amplification with cesium lithium borate.

A gain amplifier for degenerated optical parametric chirped-pulse amplification (OPCPA) with lithium triborate and cesium lithium borate (CLBO) crystals was demonstrated in a near-collinear configuration. The signal gain of the final energy amplifier with CLBO was approximately 6. After compression, the 123 fs pulse duration was obtained. Compared with potassium dihydrogen phosphate, it is confirmed that CLBO is more effective as a nonlinear crystal in a final power amplifier for terawatt or petawatt OPCPA systems. To our knowledge, this is the first demonstration of OPCPA with CLBO.

Journal Article↗

Noncritically phase-matched second-harmonic generation in cesium lithium borate.

Efficient generation of 236-nm light was demonstrated by use of noncritically phase-matched second-harmonic generation in cesium lithium borate. Noncritical phase matching provided approximately 20x the nonlinear drive for second-harmonic generation than beta-barium borate for 236-nm generation. The 236-nm wavelength is the fourth harmonic of a 946-nm Nd:YAG laser. Phase matching was accomplished at a crystal temperature of -15 degrees C.

Journal Article↗

Ultrastable cesium atomic clock with a 9.1926-GHz regeneratively mode-locked fiber laser.

We describe an ultrastable cesium (Cs) atomic clock with a 9.1926-GHz regeneratively mode-locked fiber laser obtained by use of an optically pumped Cs beam tube. By adopting a 1-m-long Cs beam tube with a linewidth of 110 Hz, we have successfully obtained frequency stabilities of 4.8 x 10(-12) for tau = 1 s and 6.3 x 10(-13) for tau = 50 s for a 9.1926-GHz microwave output signal. This Cs atomic clock can generate an optical pulse train with the same stability as that of the obtained microwave, which allows us to deliver a frequency standard optical signal throughout the world by means of optical fiber networks.

Journal Article↗

[Micromethod of ultracentrifugation in cesium chloride].

The micromethod of ultracentrifugation in cesium chloride is described. Band destributions have been analysed by the direct scanning of microtubes with the differential doublewave micro-spectrophotometer at 260 nm. The 10(-8)-10(-9) g of DNA or ribosomes are enough for one analysis, tube volume is 2 mul. The method described permits the simultaneous centrifugation of several probe scores. The error of the beyoant density determination is 0.001 g/sm3 relatively internal standard. DNA's from 5 types of Acetabularia were analysed by the developed technique.

Acetabularia↗

On the properties of solid and liquid ion exchangers. II. Infrared and NMR studies of lithium and cesium salts of dinonylnaphtalene sulfonic acid in heptane.

Infrared and NMR measurements on solutions of lithium and cesium dinonylnaphtalene sulfonates (DNNS-salts) in heptane show that the state of water in these systems is in several respects similar to its state in solid ion exchange resins and in some respects also similar to that in ordinary water. The two cations differ in their interaction with the sulfonic acid group at low water contents, the interaction being stronger for Li+. Spin-lattice relaxation measurements on LiDNNS show that the state of lithium both in DNNS and in solid resins is quite different from that of lithium salts in aqueous solutions of the corresponding concentration.

Chromatography, High Pressure Liquid↗

Measurement of dynamic end-to-end cavity phase shifts in cesium-fountain frequency standards.

We have measured a previously unobserved systematic frequency shift in our cesium-fountain frequency standard, NIST-F1. This shift, predicted theoretically previously, mimics the well-known end-to-end phase shift in atomic beam standards when synchronous thermal transients are present. Detuning the microwave cavity several megahertz from resonance reduces this effect to the deltaf/f = 1o(-16) level.

Letter↗