Thermal and Electrical Conductivity Measurements of CDA 510 Phosphor Bronze

Many cryogenic systems use electrical cables containing phosphor bronze wire. While phosphor bronze's electrical and thermal conductivity values have been published, there is significant variation among different phosphor bronze formulations. The James Webb Space Telescope (JWST) will use several phosphor bronze wire harnesses containing a specific formulation (CDA 510, annealed temper). The heat conducted into the JWST instrument stage is dominated by these harnesses, and approximately half of the harness conductance is due to the phosphor bronze wires. Since the JWST radiators are expected to just keep the instruments at their operating temperature with limited cooling margin, it is important to know the thermal conductivity of the actual alloy being used. We describe an experiment which measured the electrical and thermal conductivity of this material between 4 and 295 Kelvin

Cryogenic System for the Origins Space Telescope: Cooling a Large Space Telescope to 4K with Today's Technology

The Origins Space Telescope (OST) concept is one of four NASA Science Mission Directorate, Astrophysics Division, observatory concepts being studied for launch in the mid 2030's. OST's wavelength coverage will be from the midinfrared to the sub-millimeter, 6-600 microns. To enable observations at the zodiacal background limit the telescope must be cooled to about 4 K. Combined with the telescope size (currently the primary is 9 m in diameter) this appears to be a daunting task. However, simple calculations and thermal modeling have shown the cooling power required is met with several currently developed cryocoolers. Further, the telescope thermal architecture is greatly simplified, allowing simpler models, more thermal margin, and higher confidence in the final performance values than previous cold observatories. We will describe design principles to simplify modeling and verification. We will argue that the OST architecture and design principles lower its integration and test time and reduce its ultimate cost

Cooling the Origins Space Telescope

The NASA Astrophysics Division has commissioned 4 studies for consideration by the 2020 Decadal Survey to be the next flagship mission following WFIRST (Wide Field Infrared Survey Telescope). One of the four studies is the Origins Space Telescope (OST), which will cover wavelengths from 6 microns to 600 microns. To perform at the level of the zodiacal, galactic, and cosmic background, the telescope must be cooled to 4 degrees Kelvin. 4 degrees Kelvin multi-stage mechanical cryocoolers will be employed along with a multilayer sunshield/thermal shield to achieve this temperature with a manageable parasitic heat load. Current state-of-the-art cryocoolers can achieve close to 4 degrees Kelvin, providing about 50 megawatts of cooling at 4 degrees Kelvin with an input power of 500 watts. Multiple coolers at this power level will be used in parallel. These coolers also provide extra cooling power at intermediate temperature stages of 15-20 degrees Kelvin and 50-70 degrees Kelvin . This upper stage cooling will be used to limit the heat conducted to 4 degrees Kelvin . The multi-layer sunshield will limit the radiated thermal energy to the 4 degrees Kelvin volume. This paper will describe the architecture of the cryogenic system for OST along with preliminary thermal models

Use of Cold Radiometers in Several Thermal/Vacuum Tests

We have developed a low cost low temperature broadband radiometer for use with low temperature tests as a diagnostic tool for measuring stray thermal radiation and remote measurement of material properties. So far these radiometers have been used in two large thermal/vacuum tests for the James Webb Space Telescope (JWST) Project. In the first test the radiometers measured stray radiation in a test of part of the JWST sunshield, and in the second test the radiometers were used to measure the reflectivity and specularity of black Z307 painted aluminum walls on a 25 K cooled shroud. These results will be presented as well as plans for future tests to measure the residual energy through a baffled aperture in the shroud and other stray thermal energy measurements

Sub-Kelvin Cooling Systems for Quantum Computers

Future large-scale quantum processors (i.e. 100s of qubits), especially those based on superconducting circuits, will require large cooling powers (~10s of microW) at very low temperatures (<50 mK) with stringent temperature stabilities to avoid quantum decoherence and thus guarantee successful operation of such systems. One attractive option for providing this cooling is through Continuous Adiabatic Demagnetization Refrigerators (CADR). Scalable state-of-the-art CADRs at NASA's Goddard Space Flight Center have successfully shown to lift 6 W of heat at 50 mK with a 1 K temperature stability while rejecting its heat to a cryocooler at 4K. Carefully planned and proper heat sinking of cables, attenuators, and microwave components at various temperature stages (between 4K and base temperature) is critical in the cooling architecture of quantum computers and can be provided through proper staging of each unit within the CADR system. As an alternative method of cooling, dilution refrigerators with the potential to meet cooling requirements of emerging large-scale quantum processors are also discussed

FIRI - a Far-Infrared Interferometer

Half of the energy ever emitted by stars and accreting objects comes to us in the FIR waveband and has yet to be properly explored. We propose a powerful Far-InfraRed Interferometer mission, FIRI, to carry out high-resolution imaging spectroscopy in the FIR. This key observational capability is essential to reveal how gas and dust evolve into stars and planets, how the first luminous objects in the Universe ignited, how galaxies formed, and when super-massive black holes grew. FIRI will disentangle the cosmic histories of star formation and accretion onto black holes and will trace the assembly and evolution of quiescent galaxies like our Milky Way. Perhaps most importantly, FIRI will observe all stages of planetary system formation and recognise Earth-like planets that may harbour life, via its ability to image the dust structures in planetary systems. It will thus address directly questions fundamental to our understanding of how the Universe has developed and evolved - the very questions posed by ESA's Cosmic Vision.Comment: Proposal developed by a large team of astronomers from Europe, USA and Canada and submitted to the European Space Agency as part of "Cosmic Vision 2015-2025

Longitudinal phase-space manipulation with beam-driven plasma wakefields

The development of compact accelerator facilities providing high-brightness beams is one of the most challenging tasks in field of next-generation compact and cost affordable particle accelerators, to be used in many fields for industrial, medical and research applications. The ability to shape the beam longitudinal phase-space, in particular, plays a key role to achieve high-peak brightness. Here we present a new approach that allows to tune the longitudinal phase-space of a high-brightness beam by means of a plasma wakefields. The electron beam passing through the plasma drives large wakefields that are used to manipulate the time-energy correlation of particles along the beam itself. We experimentally demonstrate that such solution is highly tunable by simply adjusting the density of the plasma and can be used to imprint or remove any correlation onto the beam. This is a fundamental requirement when dealing with largely time-energy correlated beams coming from future plasma accelerators

The External-Injection experiment at the SPARC_LAB facility

At the SPARC_LAB facility of INFN-LNF we are installing a transport lines for ultra-short electron bunches and another for ultra-intense laser pulses,generated by the SPARC photo-injector and by the FLAME laser in asynchronized fashion at the tens of fs level,to co-propagate inside a hydrogen filled glass capillary,in order to perform acceleration of the electron bunch by a plasma wave driven by the laser pulse.The main aim of this experiment is to demonstrate that a high brightness electron beam can be accelerated by a plasma wave without any significant degradation of its quality.Motivations of the technical choices are made and expected performances are reporte

Flight Development for Cryogenic Fluid Management in Support of Exploration Missions

This paper describes the results of the "Experimentation for the Maturation of Deep Space Cryogenic Refueling Technology" study. The purposes of this study were to identify cryogenic fluids management technologies requiring low gravity flight experiments to bring to technology readiness level (TRL) 5-6; to study many possible flight experiment options; and to develop near-term low-cost flight experiment concepts to mature core technologies of refueling. A total of twenty-five white papers were prepared in the course of this study. Each white paper is briefly summarized and relevant references cited. A total of 90 references are cited

Optical Design of the Origins Space Telescope

This paper discusses the optical design of the Origins Space Telescope. Origins is one of four large missions under study in preparation for the 2020 Decadal Survey in Astronomy and Astrophysics. Sensitive to the mid- and far-infrared spectrum (between 2.8 and 588 m), Origins sets out to answer a number of important scientific questions by addressing NASAs three key science goals in astrophysics. The Origins telescope has a 5.9 m diameter primary mirror and operates at f/14. The large on-axis primary consists of 18 keystone segments of two different prescriptions arranged in two annuli (six inner and twelve outer segments) that together form a circular aperture in the goal of achieving a symmetric point spread function. To accommodate the 46 x 15 arcminute full field of view of the telescope at the design wavelength of = 30 m, a three-mirror anastigmat configuration is used. The design is diffraction-limited across its instruments fields of view. A brief discussion of each of the three baselined instruments within the Instrument Accommodation Module (IAM) is presented: 1) Origins Survey Spectrometer (OSS), 2) Mid-infrared Spectrometer, Camera (MISC) transit spectrometer channel, and 3) Far-Infrared Polarimeter/Imager (FIP). In addition, the up scope options for the observatory are laid out as well including a fourth instrument: the Heterodyne Receiver for Origins (HERO)