Final dt stickingω s using the “survived moun method”

A new direct measurement of the final dt sticking probability _s using a special data analysis called the survived muon method is presented. The data were obtained at PSI using a high pressure ionization chamber with H/D/T gas mixtures. The method can provide information on final sticking dt +n independent of theoretical models of stripping and initial sticking. It was found: _s=(0.57±0.07±0.02)%. The experiment and the analysis method are discussed in detail.     

Experimental survey of the sticking problem in muon catalyzed dt fusion

The sticking process dt + n, which constitutes the most severe limit to the number of fusions which a muon can catalyze, is reviewed. Many attempts were made to determine by calculations and measurements the probability for initial sticking _s ⁰ (immediately after dt fusion) and for final sticking _s (after the came to rest). Previous results based on neutron disappearance rates and on the observation of -X-rays were controversial and also in some disagreement with theory. New data are reported from PSI on direct observation of final sticking, using a setup with the St. Petersburg ionization chamber. These data mark a significant improvement in reliability and may clarify questions concerning previous discrepancies. The new results is _s(0.56±0.04)%, lower than the theory prediction _s=(0.65±0.03)%, at medium density.     

High resolution thermogravimetry

A new thermogravimetric instrument is introduced, Hi-Res^TM TGA 2950. The Hi-Res^TM TQA gives a significant improvement to TG results. The instrument control parameters are varied as a function of the sample's rate of weight change. This novel feature improves resolution and reduces analysis time. The maximum heating rate and resolution index are user selectable.Data presented demonstrate improved resolution for survey TG thermal curves and very high resolution for difficult to resolve complex materials. Results are demonstrated for many types of samples including: homopolymers, polymer blends, inorganic reference materials, and complex organic mixtures.Hi-Res trademark and patent applied for by TA Instruments, Inc.

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Zusammenfassung Es wird das neue thermogravimetrische Gerät Hi-Res^TMTGA2950 vorgestellt. Mit Hilfe von Hi-Res^TMTGA2950 ergibt sich eine eindeutige Verbesserung der TG-Resultate. Die Kontrollparameter des Gerätes werden als eine Funktion der Massenänderungsgeschwindigkeit der Probe geändert. Diese neue Eigenschaft verbessert die Auflösung und verringert die Analysenzeit. Maximale Aufheizgeschwindigkeit und Auflösungsindex können vom Anwender bestimmt werden.Die dargelegten Daten zeigen eine verbesserte Auflösung der TG-Kurven und eine sehr hohe Auflösung für schwer aufzulösende komplexe Substanzen. Es werden Ergebnisse für zahlreiche Beispiele gegeben: Homopolymere, Polymergemische, anorganische Referenzsubstanzen und komplexe organische Gemische.Das Warenzeichen Hi-Res und das Patent wurde von TA Instruments,Inc. beantragt.

     

Infrared multiphoton dissociation (IRMPD) and collisionally activated dissociationof peptides in a quadrupole ion trapwith selective IRMPD of phosphopeptides

Dissociation of protonated peptides via infrared multiphoton dissociation (IRMPD) provides more extensive sequence information than is obtained with collisionally activated dissociation (CAD) in a quadrupole ion trap due to the lack of the CAD low m/z cutoff and the ability to form secondary and higher order fragments with the non-resonant photoactivation technique. In addition, IRMPD is shown to be useful for the selective dissociation of phosphopeptides over those which are not phosphorylated because the greater photon absorption efficiency of the phosphorylated peptides leads to their more rapid dissociation. Finally, the selectivity of the IRMPD technique for phosphorylated species in complex mixtures is confirmed with the analysis of a mock peptide mixture and a tryptic digest of alpha-casein.     

High-spin structure of yrast-band in 78Kr

Lifetime of levels up to 22⁺, have been measured in ⁷⁸Kr and an oblate shape is assigned to the ground state using the CSM and the configuration dependent shell correction calculations. Calculations further show that ⁷⁸Kr is highly γ-soft nucleus. The experimental Q _t values coupled with theoretical calculations indicate an oblate shape for ⁷⁸Kr at low spins and triaxial shape at higher spins