Effect of metal sequestrants on the decomposition of hydroxylammonium nitrate

Hydroxylammonium nitrate (HAN) is an energetic salt used in flight-proven green monopropellants such as ASCENT (formerly AF-M315E) flown in NASA’s 2019 Green Propellant Infusion Mission and SHP163 flown in JAXA’s Rapid Innovative Satellite Technology Demonstration-1. Decomposition of HAN is catalyzed by metals commonly found in storage tanks, a factor limiting its use. This work investigates the ability of metal-sequestering chelating agents to inhibit the de-composition of HAN. Isothermal and dynamic thermogravimetric analysis (TGA) were used to find isothermal decomposition rates, decomposition onset temperatures, and first-order Arrhenius re-action rate parameters. 2,2’-bipyridine (Bipy), triethanolamine (TEA), and ethylenediaminetetraacetic acid (EDTA) were studied as 0.05, 0.1, 0.5, 1, and 5% by weight additives in 90% aqueous HAN by weight. An isothermal decomposition rate of 0.137%/hr at 348 K was observed for HAN. Addition of 1% Bipy and 1% TEA reduced the isothermal decomposition rate by 20.4% to 0.109%/hr and by 3.65% to 0.132%/hr, respectively, showing that Bipy can inhibit decomposition. The addition of 1% EDTA increased the isothermal decomposition rate by 12.4% to 0.154%/hr. Bipy was found to increase the decomposition onset temperature from 454.8 K to 461.8 K while TEA and EDTA returned inconclusive changes. First order reaction rates calculated by the Ozawa-Flynn-Wall method were found to be insufficient to capture the effects of the additives tested. Bipy was found to inhibit the decomposition of HAN, while TEA and EDTA produced little or negative effect, a result believed to be due to poor metal complex stability at low pH and high acidity, respectively. Spectrophotometry was used for colorimetric analysis of Bipy+iron complexes and showed that Bipy forms chelate complexes with trace iron impurities when added to HAN solutions

Design of a Base-Board for arrays of closely-packed Multi-Anode Photo-Multipliers

We describe the design of a Base-Board to house Multi-Anode Photo-Multipliers for use in large-area arrays of light sensors. The goals, the design, the results of tests on the prototypes and future developments are presented.Comment: 16 pages, 5 figures, submitted to Nucl. Instrum. and Meth.

The HERA-B Ring Imaging Cherenkov Counter

The HERA-B RICH uses a radiation path length of 2.8 m in C_4F_10 gas and a large 24 square meters spherical mirror for imaging Cherenkov rings. The photon detector consists of 2240 Hamamatsu multi-anode photomultipliers with about 27000 channels. A 2:1 reducing two-lens telescope in front of each PMT increases the sensitive area at the expense of increased pixel size, resulting in a contribution to the resolution which roughly matches that of dispersion. The counter was completed in January of 1999, and its performance has been steady and reliable over the years it has been in operation. The design performance of the RICH was fully reached: the average number of detected photons in the RICH for a beta=1 particle was found to be 33 with a single hit resolution of 0.7 mrad and 1 mrad in the fine and coarse granularity regions, respectively.Comment: 29 pages, 23 figure

Cooling in a compound bucket

Electron cooling in the Fermilab Recycler ring is found to create correlation between longitudinal and transverse tails of the antiproton distribution. By separating the core of the beam from the tail and cooling the tail using 'gated' stochastic cooling while applying electron cooling on the entire beam, one may be able to significantly increase the overall cooling rate. In this paper, we describe the procedure and first experimental results

Improved Limits on Spin-Dependent WIMP-Proton Interactions from a Two Liter CF3_3I Bubble Chamber

Data from the operation of a bubble chamber filled with 3.5 kg of CF$_{3}$I in a shallow underground site are reported. An analysis of ultrasound signals accompanying bubble nucleations confirms that alpha decays generate a significantly louder acoustic emission than single nuclear recoils, leading to an efficient background discrimination. Three dark matter candidate events were observed during an effective exposure of 28.1 kg-day, consistent with a neutron background. This observation provides the strongest direct detection constraint to date on WIMP-proton spin-dependent scattering for WIMP masses $>20$ GeV/c$^{2}$.Comment: 4 pages, 4 figures V2 submitted to match journal versio

Robotic Habitat Technologies for Minimizing Crew Maintenance Requirements

NASA’s Lunar Gateway aims to be deployed later in the decade and will serve as an outpost orbiting the moon. This habitat will be utilized as a base for lunar operations as well as future missions to Mars. Unlike the International Space Station (ISS), which maintains three to six astronauts at any given time, the Lunar Gateway will be uncrewed for eleven months out of the year. Over 80% of crew time onboard the ISS is dedicated to logistics, repair, and maintenance, leaving minimal time for scientific research and experimentation. In order to maintain Gateway, robotic systems must be implemented to accomplish maintenance and operational tasks. This paper discusses our team’s proposed dexterous robotic system, which will address routine and contingency operational and maintenance tasks on Gateway. The project is experimentally-based, and split into three approaches: cataloging robotic capabilities via robot/taskboard interactions, logistics management of Cargo Transfer Bags (CTBs), and software development of an AprilTag situational development system. This research project utilizes the unique capabilities of the University of Maryland (UMD) Space Systems Laboratory (SSL), which houses various dexterous robotic manipulators, mock-ups of space habitats, and the Neutral Buoyancy Research Facility (NBRF), a 50-foot diameter, 25-foot deep water tank used to simulate microgravity conditions. By incorporating robotic systems into the architecture of the Lunar Gateway, it will allow for the lunar outpost to be continually operated and maintained while uncrewed, and will allow for astronauts, when present, to focus on maximizing scientific discoveries.NASA RASC-AL 202

A muon beam for cooling experiments

Within the framework of the Fermilab Muon Collider Task Force, the possibility of developing a dedicated muon test beam for cooling experiments has been investigated. Cooling experiments can be performed in a very low intensity muon beam by tracking single particles through the cooling device. With sufficient muon intensity and large enough cooling decrement, a cooling demonstration experiment may also be performed without resolving single particle trajectories, but rather by measuring the average size and position of the beam. This allows simpler, and thus cheaper, detectors and readout electronics to be used. This paper discusses muon production using 400MeV protons from the Linac, decay channel and beamline design, as well as the instrumentation required for such an experiment, in particular as applied to testing the Helical Cooling Channel (HCC) proposed by Muons Inc