A cryogenic FMCW range-resolved laser interferometer: challenges and applications
Bibliographic record
Abstract
The continually increasing sensitivity required for the advancement of far-infrared astronomy dictates that the next generation of space-based observatories must employ cryogenically cooled telescopes and instrumentation. Operating cryogenic instrumentation in orbit poses several challenges, including the need for extremely low power dissipation and precise position measurement and control. In prior work, we reported on the development of a homodyne three-phase range-resolved laser interferometer, which demonstrated a displacement measurement uncertainty of 2:3nmrms at <4K.<sup>1</sup> Effects of low frequency noise (1=f) in the electrical signals at low velocities were performance limiting due to the interpretation of noise as interference fringes. To avoid 1=f noise, a frequency-modulated continuous-wave (FMCW) heterodyne approach was adopted. An FMCW prototype was developed, and the preliminary results yielded an uncertainty of 29nmrms at <4K.<sup>2</sup> In this paper we present the design of an integrated cryogenic FMCW range-resolved laser interferometer which features real time data processing for simultaneous displacement measurements of up to 8 axes. The performance of fibers and their coupling under ultra-high vacuum at cryogenic temperatures is largely unexplored, and we present the cryogenic characterization results of several key variables, including fiber type, termination, and mating, along with alignment effects due to the thermal contraction of fiber components. These results have been incorporated into the design of our cryogenic FMCW interferometer. Applications of cryogenic range resolved interferometry are discussed, with a focus on the integration of the FMCW interferometer with a custom 3-axis cryogenic accelerometer.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".