Energy spread of ultracold electron bunches extracted from a laser cooled gas

Ultrashort and ultracold electron bunches created by near-threshold femtosecond photoionization of a laser-cooled gas hold great promise for single-shot ultrafast diffraction experiments. In previous publications the transverse beam quality and the bunch length have been determined. Here the longitudinal energy spread of the generated bunches is measured for the first time, using a specially developed Wien filter. The Wien filter has been calibrated by determining the average deflection of the electron bunch as a function of magnetic field. The measured relative energy spread $\frac{\sigma_{U}}{U} = 0.64 \pm 0.09\%$ agrees well with the theoretical model which states that it is governed by the width of the ionization laser and the acceleration length

Assembling the genomes of the plastid and mitochondrion of white spruce (Picea glauca)

<p>The genome sequences of the plastid and mitochondrion of white spruce (<em>Picea glauca</em>) are assembled from whole genome Illumina sequencing data using ABySS and aligned to the Norway spruce (<em>Picea abies</em>) using BWA-MEM. The putative mitochondrial sequences are classified using k-means clustering in R. The plastid genome is 120 kbp, and the putative mitochondrial genome is 6 Mbp.</p