Multi-nucleon transfer reactions at ion catcher facilities - a new way to produce and study heavy neutron-rich nuclei

Abstract The production of very neutron-rich nuclides heavier than fission fragments is an ongoing experimental challenge. Multi-nucleon transfer reactions (MNT) have been suggested as a method to produce these nuclides. By thermalizing the reaction products in gas-filled stopping cells, we can deliver them as cooled high-quality beams to decay, laser and mass spectrometry experiments. High precision mass spectrometry will allow for the first time to universally and unambiguously identify the atomic and proton numbers of the ions produced in MNT reactions. In this way their ground and isomeric state properties can be studied in high-precision measurements. In experiments at IGISOL, Finland and at FRS Ion Catcher, Germany, we have done and will perform broadband measurements of the reaction products, with the aim to improve the understanding of the reaction mechanism and to determine the properties of the ground and isomeric states of the produced nuclides. First results and preparations for upcoming experiments are presented.

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Repair of DNA Alkylation Damage by theEscherichia coliAdaptive Response Protein AlkB as Studied by ESI-TOF Mass Spectrometry

Journal of Nucleic Acids ◽

10.4061/2010/369434 ◽

2010 ◽

Vol 2010 ◽

pp. 1-9 ◽

Cited By ~ 8

Author(s):

Deyu Li ◽

James C. Delaney ◽

Charlotte M. Page ◽

Alvin S. Chen ◽

Cintyu Wong ◽

...

Keyword(s):

Mass Spectrometry ◽

Chemical Oxidation ◽

Dna Alkylation ◽

Reaction Products ◽

Ionization Time ◽

Alkylation Damage ◽

Living Organisms ◽

First Time ◽

Dependent Mechanism

DNA alkylation can cause mutations, epigenetic changes, and even cell death. All living organisms have evolved enzymatic and non-enzymatic strategies for repairing such alkylation damage. AlkB, one of theEscherichia coliadaptive response proteins, uses an α-ketoglutarate/Fe(II)-dependent mechanism that, by chemical oxidation, removes a variety of alkyl lesions from DNA, thus affording protection of the genome against alkylation. In an effort to understand the range of acceptable substrates for AlkB, the enzyme was incubated with chemically synthesized oligonucleotides containing alkyl lesions, and the reaction products were analyzed by electrospray ionization time-of-flight (ESI-TOF) mass spectrometry. Consistent with the literature, but studied comparatively here for the first time, it was found that 1-methyladenine, 1,N6-ethenoadenine, 3-methylcytosine, and 3-ethylcytosine were completely transformed by AlkB, while 1-methylguanine and 3-methylthymine were partially repaired. The repair intermediates (epoxide and possibly glycol) of 3,N4-ethenocytosine are reported for the first time. It is also demonstrated thatO6-methylguanine and 5-methylcytosine are refractory to AlkB, lending support to the hypothesis that AlkB repairs only alkyl lesions attached to the nitrogen atoms of the nucleobase. ESI-TOF mass spectrometry is shown to be a sensitive and efficient tool for probing the comparative substrate specificities of DNA repair proteinsin vitro.

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High precision measurements of arsenic implantation dose in silicon by secondary ion mass spectrometry

10.1063/1.1354476 ◽

2001 ◽

Author(s):

P. H. Chi

Keyword(s):

Mass Spectrometry ◽

High Precision ◽

Secondary Ion Mass Spectrometry ◽

Implantation Dose ◽

Precision Measurements ◽

Ion Mass Spectrometry ◽

Secondary Ion

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First Determination of the Proton's Weak Charge

Journal of Student Science and Technology ◽

10.13034/jsst.v8i3.94 ◽

2015 ◽

Vol 8 (3) ◽

Author(s):

Shelley A. Page

Keyword(s):

Standard Model ◽

High Precision ◽

Standard Model Prediction ◽

Data Set ◽

Weak Charge ◽

Newport News ◽

The Standard Model ◽

First Results ◽

First Time

The weak charge of the proton has been determined for the first time via a high precision electron-proton scattering experiment, Qweak, carried out at Jefferson Laboratory (JLab) in Newport News, USA. The weak charge is a basic property in subatomic physics, analogous to electric charge. The Standard Model makes a prediction for the weak charges of protons and other particles. First results described here are based on an initial 4% of the data set reported in 20131, with the ultimate goal of the experiment being a high precision Standard Model test conducted with the full Qweak data set. These initial results are consistent with the Standard Model prediction; they serve as an important first determination of the proton’s weak charge and a proof of principle that the ultimate goals are within reach.

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