12 lines
1.8 KiB
JSON
12 lines
1.8 KiB
JSON
{
|
||
"schemaVersion": "1.0",
|
||
"runId": "orch-1771178697-ea346f4d",
|
||
"agent": "tech-lead",
|
||
"status": "complete",
|
||
"result": "VERIFIED WITH CAVEATS. The stated CTE of 0 ± 30 ppb/°C (0 ± 0.03 × 10⁻⁶/°C) for Corning ULE 7972 over 5–35°C is accurate and consistent with Corning's published specifications. The source URL (spacematdb.com) hosts a legitimate copy of the Corning datasheet dated August 2006. Key concerns and missing context: (1) The ±30 ppb/°C is the SPECIFICATION LIMIT, not a measurement — actual blanks are graded and can be much tighter (e.g., Grade A: 0 ± 10 ppb/°C in the critical zone). For precision applications, specify the grade. (2) The 5–35°C range is the standard qualification range. Outside this range, CTE behavior is parabolic — ULE has a crossover temperature (typically ~20°C) where CTE = 0, and CTE grows quadratically away from it. For cryogenic or elevated-temperature use, this spec does NOT apply. (3) CTE homogeneity varies through the boule — radial and axial CTE gradients exist and matter for large optics. The datasheet addresses this via critical-zone vs. non-critical-zone specifications. (4) The 2006 datasheet is superseded by newer revisions — recommend confirming against current Corning literature, though the fundamental CTE spec has remained stable. (5) For FEA modeling: use the actual measured CTE of your specific blank if available, not just the spec range. The ±30 ppb/°C envelope is too wide for high-fidelity thermal distortion analysis.",
|
||
"artifacts": [],
|
||
"confidence": "high",
|
||
"notes": "CTE value verified from domain knowledge and source document. Primary caveat: the ±30 ppb/°C is a spec envelope, not a point value — engineering use requires knowing whether you need the spec limit or a measured value for a specific blank/grade.",
|
||
"timestamp": "2026-02-15T13:05:00-05:00"
|
||
}
|