Ra+ ion trapping: toward an atomic parity violation measurement and an optical clock

A single Ra⁺ ion stored in a Paul radio frequency ion trap has excellent potential for a precision measurement of the electroweak mixing angle at low momentum transfer and as the most stable optical clock. The effective transport and cooling of singly charged ions of the isotopes ²⁰⁹Ra to ²¹⁴Ra in a gas filled radio frequency quadrupole device is reported. The absolute frequencies of the transition 7s²S_1/2–7d²D_3/2 at wavelength 828 nm have been determined in ^212–214Ra⁺ with ≤19 MHz uncertainty using laser spectroscopy on small samples of ions trapped in a linear Paul trap at the online facility Trapped Radioactive Isotopes: µicrolaboratories for fundamental Physics (TRIµP) of the Kernfysisch Versneller Instituut.     

Untersuchung von Seifen

Ohne Zusammenfassung     

Measurement and compensation of frequency chirping in pulsed dye laser amplifiers

Rapid changes of the refractive index in the active medium of a pulsed, excimer laser pumped dye laser amplifier were investigated with an optical heterodyne technique. Time-dependent shifts in the phase of optical light waves could be observed which for Coumarin 102, 153 and 307 dyes at wavelengths of 488 and 550 nm depend predominantly on the thermal properties, in particular, on the expansitivity of the dye solutions. A fast Electro-Optic Modulator (EOM) using LiTaO₃ crystals has been designed for compensating these phase perturbations. With appropriately shaped voltage pulses applied to the EOM the resulting changes in the instantaneous frequency of the pulsed laser output could be lowered by a factor of 4 with respect to the values measured in the uncompensated light.Prof. F.P. Schäfer on the occasion of his 65th birthday.     

Pentopyranosyl Oligonucleotide Systems. Communication No. 13

Among the members of a family of diastereoisomeric pentopyranosyl‐(4′→2′)‐oligonucleotide systems derived from D ‐ribose, D ‐xylose, L ‐lyxose, and L ‐arabinose, the α‐arabinopyranosyl system shows by far the strongest Watson? Crick base pairing. The system is, in fact, one of the strongest oligonucleotide‐type base‐pairing systems known. It undergoes efficient cross‐pairing with all the other members of the pentopyranosyl family, but not with RNA and DNA. The paper describes the synthesis and pairing of the properties of α‐L ‐arabinopyranosyl‐(4′→2′)‐oligonucleotides.     

Radical cyclization of sugar-derived beta-(alkynyloxy)acrylates: synthesis of novel fused ethers

[formula: see text] Tributyltin radical mediated cyclization of carbohydrate-derived beta-(alkynyloxy)acrylates leading to highly functionalized cis- and trans-fused bicyclic ethers of various ring sizes is described. The efficacy of the radical cyclization is nicely illustrated in the iterative construction of a trans-fused tricyclic tetrahydropyran.     

Tests of fundamental symmetries and interactions – using nuclei and lasers

State of the art laser technology and modern spectroscopic methods allow to address issues of fundamental symmetries and fundamental interactions in atoms with high precision experiments. In particular the discrete symmetries Parity (P), Charge Conjugation (C), Time Reversal (T) as well as their combinations CP and CPT are in the center of interest at present. Actual projects are concerned with Parity Violation in atoms, Time Reversal Violation in β-decays and searches for permanent Electric Dipole Moments (EDMs), and tests of CPT conservation in particle-antiparticle properties, in particular antiprotonic atoms. This work is supported in part by the Dutch Stichting voor Fundamenteel Onderzoek der Materie (FOM) under programme number 48 (TRIμP).