Q Capability Indications from Infrared Absorption Measurements for Na₂CO₃Process Cultured Quartz

Abstract

A group of 5 MHz 5th overtone quartz crystal resonators made from Na2C03 process, slow grown cul- tured quartz were measured for their extinction coefficients at 3500 cm.-' (0~~~~~'s) and Q's by the amplitude decrement method at room temperature. Alphas ranged from 0.02 to 0.3 cm-' (kO.01 reproducibility) and the Q's from 3,000,000 to 500,000 (k3% reproducibility). A smoothed curve approximating the data is given by: lo6 -_ - 0.1 14 + 7.47~1- 0.450~. Q It is roughly parallel to, but offset toward higher alphas (in the low alpha range only) from the one reported by Fraser, Dodd, Rudd and Carroll (3) for room temperature Q in NaOH process fast-grown quartz for alphas ranging up to 2.0 cm-'