aCORN: An experiment to measure the electron-antineutrino correlation coefficient in free neutron decay.

We describe an apparatus used to measure the electron-antineutrino angular correlation coefficient in free neutron decay. The apparatus employs a novel measurement technique in which the angular correlation is converted into a proton time-of-flight asymmetry that is counted directly, avoiding the need for proton spectroscopy. Details of the method, apparatus, detectors, data acquisition, and data reduction scheme are presented, along with a discussion of the important systematic effects.

Ion beam production with sub-milligram samples of material from an ECR source for AMS.

Current accelerator mass spectrometry experiments at the Argonne Tandem Linac Accelerator System facility at Argonne National Laboratory push us to improve the ion source performance with a large number of samples and a need to minimize cross contamination. These experiments can require the creation of ion beams from as little as a few micrograms of material. These low concentration samples push the limit of our current efficiency and stability capabilities of the electron cyclotron resonance ion source. A combination of laser ablation and sputtering techniques coupled with a newly modified multi-sample changer has been used to meet this demand. We will discuss performance, stability, and consumption rates as well as planned improvements.

Small mammal studies in a SAD baiting area.

Studies in the laboratory or in the field on the effect of SAD virus on small rodents are reported. Laboratory experiments by oral inoculation of SAD strain in a wide variety of small mammals led to the conclusion that spontaneous SAD transmission from rodent to rodent is a rare event. Field experiments were conducted by live-trapping, sacrifice and analysis of 192 Apodemus sylvaticus, 28 Clethrionomys glareolus and 48 Crocidura russula. They gave no indication that SAD virus became established in this small animal community on an island after a single exposure to a high density (300 sites on 10 hectares) of vaccine baits.

Progress of laser ablation for accelerator mass spectroscopy at ATLAS utilizing an ECRIS.

Beams of ions from the laser ablation method of solid materials into an electron cyclotron resonance ion source (ECRIS) plasma have been used for the first time in experiments at ATLAS. Initial accelerator mass spectroscopy experiments using laser ablation for actinides and samarium have been performed. Initial results of coupling the laser system to the ECR source have guided us in making a number of changes to the original design. The point of laser impact has been moved off axis from the center of the ECR injection side. Motor control of the laser positioning mirror has been replaced with a faster and more reliable piezo-electric system, and different raster scan patterns have been tested. The use of the laser system in conjunction with a multi-sample changer has been implemented. Two major problems that are being confronted at this time are beam stability and total beam intensity. The status of the development will be presented and ideas for further improvements will be discussed.