SuperCDMS Detector Readout Cryogenic Hardware

SuperCDMS employs 1‐inch thick germanium crystals operated below 50mK in a dilution cryostat. Each detector produces ionization and phonon signals. Ionization signals are amplified by JFETs operating at 150K within an assembly mounted on the 4K cryostat stage. These high impedance signals are carried to the FETs by superconducting “vacuum coaxes” which minimize thermal conductivity, stray capacitance, and microphonics. Transition edge sensors produce low‐impedance phonon signals, amplified by SQUID arrays mounted on a 600mK stage. Detectors are mounted in a six‐sided wiring configuration called a “tower”, which carries signals from 40mK to 4K. A flex circuit 3 meters in length carries amplified signals for each detector from 4K to a vacuum bulkhead. We describe the methods used to support the detectors, wiring and amplifier elements at various thermal stages, minimizing electrical noise and thermal loads

Evaluating effects of chemical weathering and surface contamination on the in situ provenance analysis of building stones in the Cuzco region of Peru with portable XRF

As the only type of instrument capable of determining artifact geochemistry in a wide variety of settings, portable X-Ray Fluorescence (PXRF) may be frequently utilized as probably the best option for collecting data when removal of objects in part or in whole is unfeasible. However, using PXRF in circumstances where sample selection and preparation diverge from standards developed for lab-based instrumentation requires assessing the impact of new and potentially limiting factors to establish the validity of the method in these new contexts. Here we examine the effects of surface contamination and chemical weathering on the ability to assess provenance of igneous building stones used in the Cuzco region of Peru. Surface contamination was assessed through comparing low-impact cleaning methods on diorite and andesite blocks, and weathering was examined by comparing weathered vs. fresh surfaces of samples from two andesite quarries. In general, the lightest elements were most impacted by contamination and weathering while measurements of many of the heavier elements commonly used in provenance studies were relatively unaffected. Concentrations of Pb and Zn were problematic in the urban context of Cuzco because of pollution. Ability to determine provenance of building stones within those limitations (i.e., the validity of this application of PXRF) was demonstrated in a preliminary study by comparing measurements from uncleaned, exposed building stones in the region to fresh quarry samples

The Cryogenic Dark Matter Search (CDMS) experiment: Results, status and perspective

The Cryogenic Dark Matter Search experiment (CDMS) is using Phonon+Ionization detectors to search for Dark Matter in the form of Weakly Interactive Massive Particles (WIMPs). We report on new results from the operation of CDMS five “towers” at Soudan underground laboratory. With new and more massive detectors, SuperCDMS project has been started since March 2009. We report on the current status of SuperCDMS and its perspective

Bulk and Surface Charge Collection: CDMS Detector Performance and Design Implications

The Cryogenic Dark Matter Search (CDMS) searches for Weakly Interacting Massive Particles (WIMPs) with cryogenic germanium particle detectors. These detectors discriminate between nuclear‐recoil candidate and electron‐recoil background events by collecting both phonon and ionization energy from interactions in the crystal. Incomplete ionization collection results in the largest background in the CDMS detectors as this causes electron‐recoil background interactions to appear as false candidate events. Two primary causes of incomplete ionization collection are suface and bulk charge trapping. Recent work has been focused on reducing surface trapping through the modification of fabrication methods for future detectors. Analyzing data taken with test devices shows that hydrogen passivation of the amorphous silicon blocking layer does not reduce the effects of surface trapping. Other data shows that the iron‐ion implantation used to lower the critical temperature of the tungsten transition‐edge sensors increases surface trapping, causing a degradation of the ionization collection. Using selective implantation on future detectors may improve ionization collection for events near the phonon side detector surface. Bulk trapping is minimized by neutralizing ionized lattice impurities. Detector investigations at testing facilities and at the experimental site in Soudan, MN have provided methods to optimize the neutralization process and monitor running conditions to maintain maximal ionization collection

Piloted Simulation Assessment of the Impact of Flexible Structures on Handling Qualities of Generic Supersonic Aircraft

The NASA Langley Research Center Cockpit Motion Facility (CMF) was used to conduct a piloted simulation assessment of the impact of flexible structures on flying qualities. The CMF was used because of its relatively high bandwidth, six degree-of-freedom motion capability. Previous studies assessed and attempted to mitigate the effects of multiple dynamic aeroservoelastic modes (DASE). Those results indicated problems existed, but the specific cause and effect was difficult to ascertain. The goal of this study was to identify specific DASE frequencies, damping ratios, and gains that cause degradation in handling qualities. A generic aircraft simulation was developed and designed to have Cooper-Harper Level 1 handling qualities when flown without DASE models. A test matrix of thirty-six DASE modes was implemented. The modes had frequencies ranging from 1 to 3.5 Hz and were applied to each axis independently. Each mode consisted of a single axis, frequency, damping, and gain, and was evaluated individually by six subject pilots with test pilot backgrounds. Analysis completed to date suggests that a number of the DASE models evaluated degrade the handling qualities of this class of aircraft to an uncontrollable condition

Measuring vertebrate telomeres: applications and limitations

Telomeres are short tandem repeated sequences of DNA found at the ends of eukaryotic chromosomes that function in stabilizing chromosomal end integrity. In vivo studies of somatic tissue of mammals and birds have shown a correlation between telomere length and organismal age within species, and correlations between telomere shortening rate and lifespan among species. This result presents the tantalizing possibility that telomere length could be used to provide much needed information on age, ageing and survival in natural populations where longitudinal studies are lacking. Here we review methods available for measuring telomere length and discuss the potential uses and limitations of telomeres as age and ageing estimators in the fields of vertebrate ecology, evolution and conservation

Primary care treatment of insomnia: study protocol for a pragmatic, multicentre, randomised controlled trial comparing nurse-delivered sleep restriction therapy to sleep hygiene (the HABIT trial).

Introduction Insomnia is a prevalent sleep disorder that negatively affects quality of life. Multicomponent cognitive-behavioural therapy (CBT) is the recommended treatment but access remains limited, particularly in primary care. Sleep restriction therapy (SRT) is one of the principal active components of CBT and could be delivered by generalist staff in primary care. The aim of this randomised controlled trial is to establish whether nurse-delivered SRT for insomnia disorder is clinically and cost-effective compared with sleep hygiene advice. Methods and analysis In the HABIT (Health-professional Administered Brief Insomnia Therapy) trial, 588 participants meeting criteria for insomnia disorder will be recruited from primary care in England and randomised (1:1) to either nurse-delivered SRT (plus sleep hygiene booklet) or sleep hygiene booklet on its own. SRT will be delivered over 4 weekly sessions; total therapy time is approximately 1 hour. Outcomes will be collected at baseline, 3, 6 and 12 months post-randomisation. The primary outcome is self-reported insomnia severity using the Insomnia Severity Index at 6 months. Secondary outcomes include health-related and sleep-related quality of life, depressive symptoms, use of prescribed sleep medication, diary and actigraphy-recorded sleep parameters, and work productivity. Analyses will be intention-to-treat. Moderation and mediation analyses will be conducted and a cost-utility analysis and process evaluation will be performed. Ethics and dissemination Ethical approval was granted by the Yorkshire and the Humber - Bradford Leeds Research Ethics Committee (reference: 18/YH/0153). We will publish our primary findings in high-impact, peer-reviewed journals. There will be further outputs in relation to process evaluation and secondary analyses focussed on moderation and mediation. Trial results could make the case for the introduction of nurse-delivered sleep therapy in primary care, increasing access to evidence-based treatment for people with insomnia disorder