Cryogenic characterization and testing of magnetically-actuated microshutter arrays for the James Webb Space Telescope

King, Todd; Kletetschka, Günther; Jah, Muzariatu A.; Beamesderfer, Michael; Li, M J; Wang, L L; Moseley, S. H.; Sparr, Leroy; Jhabvala, M.; Kutyrev, A.; Silverberg, R. F.; Rapchun, David A.; Zheng, Yun; Schwinger, D. S.; Voellmer, George M.

doi:10.1088/0960-1317/15/8/031

Cited by 9 publications

(2 citation statements)

References 9 publications

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“…Once the material achieves a temperature of 50 K, the lattice reduction rate slows down and fracture frequency stops. 22 Thermal stress-induced fractures render cryopreserved frozen tissue unusable for transplantation. 23 Rewarming of such frozen tissue with fractures results in bleeding and medical complications during the cryosurgery.…”

Section: Fracturing Of Solids When Lowering the Temperaturementioning

confidence: 99%

Dissolved Gases and Ice Fracturing During the Freezing of a Multicellular Organism: Lessons from Tardigrades

Kletetschka

Hruba

2015

BioResearch Open Access

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Three issues are critical for successful cryopreservation of multicellular material: gases dissolved in liquid, thermal conductivity of the tissue, and localization of microstructures. Here we show that heat distribution is controlled by the gas amount dissolved in liquids and that when changing the liquid into solid, the dissolved gases either form bubbles due to the absence of space in the lattice of solids and/or are migrated toward the concentrated salt and sugar solution at the cost of amount of heat required to be removed to complete a solid-state transition. These factors affect the heat distribution in the organs to be cryopreserved. We show that the gas concentration issue controls fracturing of ice when freezing. There are volumetric changes not only when changing the liquid into solid (volume increases) but also reduction of the volume when reaching lower temperatures (volume decreases). We discuss these issues parallel with observations of the cryosurvivability of multicellular organisms, tardigrades, and discuss their analogy for cryopreservation of large organs.

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Section: Fracturing Of Solids When Lowering the Temperaturementioning

confidence: 99%

Dissolved Gases and Ice Fracturing During the Freezing of a Multicellular Organism: Lessons from Tardigrades

Kletetschka

Hruba

2015

BioResearch Open Access

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“…Tests of arrays fabricated during the process development have been obtained which suggest that significant infant mortality of shutters may occur. 16 To assess the actual performance of the shutter arrays we have designed and built a microshutter functional and optical test facility. This facility allows to subject the arrays to repeated actuation and latching process at accelerated rate.…”

Section: Microshutter Array Performancementioning

confidence: 99%

Microshutter arrays: high contrast programmable field masks for JWST NIRSpec

Kutyrev

Collins

Chambers

et al. 2008

Space Telescopes and Instrumentation 2008: Optical, Infrared, and Millimeter

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Microshutter arrays are one of the novel technologies developed for the James Webb Space Telescope (JWST). It will allow Near Infrared Spectrometer (NIRSpec) to acquire spectra of hundreds of objects simultaneously therefore increasing its efficiency tremendously. We have developed these programmable arrays that are based on Micro-Electro Mechanical Structures (MEMS) technology. The arrays are 2D addressable masks that can operate in cryogenic environment of JWST. Since the primary JWST science requires acquisition of spectra of extremely faint objects, it is important to provide very high contrast of the open to closed shutters. This high contrast is necessary to eliminate any possible contamination and confusion in the acquired spectra by unwanted objects. We have developed and built a test system for the microshutter array functional and optical characterization. This system is capable of measuring the contrast of the mciroshutter array both in visible and infrared light of the NIRSpec wavelength range while the arrays are in their working cryogenic environment. We have measured contrast ratio of several microshutter arrays and demonstrated that they satisfy and in many cases far exceed the NIRSpec contrast requirement value of 2000.

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Metrology of infrared superconducting bolometers with a backshort

Rostem

Brown

Petit

et al. 2023

Review of Scientific Instruments

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We present the detailed metrology of a superconducting Transition-Edge Sensor (TES) absorber-coupled bolometer array bonded to a variable-delay backshort to form an integral field unit. The backshort is shaped as a wedge to continuously vary the electrical phase delay of the bolometer absorber reflective termination across the array. This resonant absorber termination structure is used to define a spectral response over a 4:1 bandwidth in the far-infrared, from ∼30 to 120 μm. The metrology of the backshort-bolometer array hybrid was achieved with a laser confocal microscope and a compact cryogenic system that provides a well-defined thermal (radiative and conductive) environment for the hybrid when cooled to ∼10 K. The results show the backshort free-space delays do not change with cooling. The estimated backshort slope is 1.58 milli-radians and within 0.3% of the targeted value. The sources of error in the free-space delay of the hybrid and optical cryogenic metrology implementations are discussed in detail. We also present measurements of the bolometer’s single-crystal silicon membrane topography. The membranes deform and deflect out-of-plane under both warm and cold conditions. Intriguingly, the optically active area of the membranes tends to flatten when cold and repeatably achieve the same mechanical state over many thermal cycles; hence, no evidence for thermally-induced mechanical instability is observed. Most of the cold deformation is sourced from thermally-induced stress in the metallic layers comprising the TES element of the bolometer pixels. These results provide important considerations for the design of ultra-low-noise TES bolometers.

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Cryogenic characterization and testing of magnetically-actuated microshutter arrays for the James Webb Space Telescope

Cited by 9 publications

References 9 publications

Dissolved Gases and Ice Fracturing During the Freezing of a Multicellular Organism: Lessons from Tardigrades

Dissolved Gases and Ice Fracturing During the Freezing of a Multicellular Organism: Lessons from Tardigrades

Microshutter arrays: high contrast programmable field masks for JWST NIRSpec

Metrology of infrared superconducting bolometers with a backshort

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