Measurement of ultra‐heavy cosmic rays at a lunar base

A wealth of information regarding cosmic ray synthesis and propagation is contained in the ultra‐heavy (Z≳60) cosmic ray abundances; to extract this information, however, requires a detector capable of acquiring large statistics for these rare particles, as well as a charge resolution adequate to separate neighboring charge peaks at very large Z. A large, passive surface array of nuclear‐track‐detecting glass plates would meet these requirements. These glass plates could be periodically processe and analyzed for tracks at a lunar base, then melted/annealed for reuse in a continuously recycled detector array.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87613/2/42_1.pd

Measurement of Reciprocity Failure in Near Infrared Detectors

Flux dependent non-linearity (reciprocity failure) in HgCdTe near infrared detectors can severely impact an instrument's performance, in particular with respect to precision photometric measurements. The cause of this effect is presently not understood. To investigate reciprocity failure, a dedicated test system was built. For flux levels between 1 and 50,000 photons/s, a sensitivity to reciprocity failure of approximately 0.1%/decade was achieved. A wavelength independent non-linearity due to reciprocity failure of about 0.35%/decade was measured in a 1.7 micron HgCdTe detector.Comment: 7 pages, 8 figure

A New RL Constant for the Calculation of log P and n Values in Congeneric Compounds

Retention volumes of iodinated diethylstilbestrols and estradiols measured by high-pressure liquid chromatography on a silica column were found to be linearly related to their experimental partition coefficients (log P). The log P values calculated from the new RL parameter correlate well with experimental values and with those calculated by Hansch :n:-constants. The magnitudes of it-values for iodine in monosubstituted estradiols are discussed in terms of the contribution of steric and »proximity« effects to these constants. The reported technique may be a significant addition to the methodology of obtaining lipophylic-hydrophylic constants in structure- activity relationship studies

Aromatic Iodination of Diethylstilbestrol Diphosphate

Sterically crowded estrogenic compound diethylstilbestrol diphosphate was successfully polyiodinated on the aromatic rings applying an electrochemical procedure. The reported synthesis also opens the way for the preparation of potentially useful radiolabelled cancer chemotherapeutics

Status of cosmic-ray antideuteron searches

The precise measurement of cosmic-ray antiparticles serves as important means for identifying the nature of dark matter. Recent years showed that identifying the nature of dark matter with cosmic-ray positrons and higher energy antiprotons is difficult, and has lead to a significantly increased interest in cosmic-ray antideuteron searches. Antideuterons may also be generated in dark matter annihilations or decays, offering a potential breakthrough in unexplored phase space for dark matter. Low-energy antideuterons are an important approach because the flux from dark matter interactions exceeds the background flux by more than two orders of magnitude in the low-energy range for a wide variety of models. This review is based on the "dbar14 - dedicated cosmic-ray antideuteron workshop", which brought together theorists and experimentalists in the field to discuss the current status, perspectives, and challenges for cosmic-ray antideuteron searches and discusses the motivation for antideuteron searches, the theoretical and experimental uncertainties of antideuteron production and propagation in our Galaxy, as well as give an experimental cosmic-ray antideuteron search status update. This report is a condensed summary of the article "Review of the theoretical and experimental status of dark matter identification with cosmic-ray antideuteron" (arXiv:1505.07785).Comment: 9 pages, 4 figures, ICRC 2015 proceeding

Near infrared detectors for SNAP

Large format (1k x 1k and 2k x 2k) near infrared detectors manufactured by Rockwell Scientific Center and Raytheon Vision Systems are characterized as part of the near infrared R&D effort for SNAP (the Super-Nova/Acceleration Probe). These are hybridized HgCdTe focal plane arrays with a sharp high wavelength cut-off at 1.7 um. This cut-off provides a sufficiently deep reach in redshift while it allows at the same time low dark current operation of the passively cooled detectors at 140 K. Here the baseline SNAP near infrared system is briefly described and the science driven requirements for the near infrared detectors are summarized. A few results obtained during the testing of engineering grade near infrared devices procured for the SNAP project are highlighted. In particular some recent measurements that target correlated noise between adjacent detector pixels due to capacitive coupling and the response uniformity within individual detector pixels are discussed

The Desi Spectrograph System and Production

The Dark Energy Spectroscopic Instrument (DESI) is a project in construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14,000 square degrees will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs covering a 360 - 980 nm passband with a spectral resolution (λ/Δλ) between 1500 and 4000. The spectrograph uses two dichroic beam splitters to separate the flux among three spectral cameras, each with a volume phase holographic grating and lens system that focuses onto a charge coupled device detector. We describe the spectrograph, its system requirements, design and construction

Precision alignment and integration of DESI's focal plane using a laser tracker

The recently commissioned Dark Energy Spectroscopic Instrument (DESI) will measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14000 sq deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope delivers light to 5000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs. We describe the use of a Faro Laser Tracker with custom hardware and software tools for alignment during integration of DESI’s focal plane. The focal plane is approximately one meter in diameter and consists primarily of ten radially symmetrical focal plane segments (“petals”) which were individually installed into the telescope. The nominal clearance between petals is 600 microns, and an alignment accuracy of 100 microns and 0.01 degrees was targeted. Alignment of the petals to their targeted locations on the telescope was accomplished by adjusting a purpose-built alignment structure with 14 degrees of freedom using feedback from the laser tracker, which measured the locations of retroreflectors attached to both the petal and the telescope and whose positions relative to key features were precisely known. These measurements were used to infer the locations of aligning features in both structures, which were in turn used to calculate the adjustments necessary to bring the system into alignment. Once alignment was achieved to within acceptable tolerances, each petal was installed while monitoring building movement due to wind and thermal variations