Gas modulation refractometry for high-precision assessment of pressure under non-temperature-stabilized conditions

Silander, Isak; Hausmaninger, Thomas; Zelán, Martin; Axner, Ove

doi:10.1116/1.5022244

Cited by 28 publications

(47 citation statements)

References 35 publications

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“…Figure 7(a) presents, by the individual markers, the external pressure assessed by use of the refractometer, denoted R P , as a function of the estimated pressure of the piston gauge, dw P , calculated by use of Eq. (4) in Silander et al 28 , for seven different weights. The data series were taken over a period of 8 days in a non-consecutive order (2841, 4303, 7225, 10148, 3426, 5764, and 8687 Pa).…”

Section: B Linearitymentioning

confidence: 94%

“…1, is based to a large degree on that for SCM-GAMOR. 28 28 The left out parts for arm 2 are identical to those of arm 1.…”

Section: Methodsmentioning

confidence: 99%

“…As an upgrade compared to the previous GAMOR system, 28 the temperature of the cavity spacer is monitored by six Pt-100 sensors (RS Pro PT100 Sensor, 457-3710) that are placed in holes drilled into the cavity spacer for monitoring of the temperature and its distribution in the spacer. The holes were bored so that the distance between the sensors and the measurement cavity wall is 5 mm.…”

Section: Methodsmentioning

confidence: 99%

“…As has been described in the literature, 28 and as is shortly summarized in the methodology section below, the soul of the GAMOR methodology consists of a methodology to obtain an adequate estimate of the evacuated measurement cavity beat frequency at the time of the filled measurement cavity assessment. The evacuated measurement cavity beat frequency used for calculation of the shift in beat frequency is estimated by a linear interpolation from two evacuated measurement cavity reference measurements performed just prior to, and directly after, the filled measurement cavity assessment.…”

Section: A Scm-gamormentioning

confidence: 99%

“…The performance of the novel system is compared to that of the first realization of GAMOR, 28 henceforth referred to as Single Cavity Modulated GAMOR (SCM-GAMOR). It is shown that GEq-GAMOR can provide a two times better precision under short-term conditions and that the drifts have been reduced significantly (more than 8 times for integration times for 500 measurement cycles, or 18 hours).…”

Section: Introductionmentioning

confidence: 99%

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Gas equilibration gas modulation refractometry for assessment of pressure with sub-ppm precision

Silander

Hausmaninger

Forssén

et al. 2019

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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Gas Modulation Refractometry (GAMOR) has recently been developed to mitigate drifts in the length of the cavities in Dual-Fabry-Perot Cavity (DFPC) based refractometry. By performing repeated reference assessments with the measurement cavity being evacuated while the reference cavity is held at a constant pressure, the methodology can reduce the influence of the long-term drifts, allowing it to benefit from the high precision of DFPCbased refractometry at short time scales. A novel realization of GAMOR, referred to as Gas Equilibration GAMOR (GEq-GAMOR), that outperforms the original realization of GAMOR, here referred to as Single Cavity Modulated GAMOR (SCM-GAMOR), is presented. It is based upon the fact that the reference measurements are carried out by equalizing the pressures in the two cavities. By this, the time it takes to reach adequate 2 conditions for the reference measurements has been reduced. This implies that a larger fraction of the measurement cycle can be devoted to data acquisition, which reduces white noise and improves on its short-term characteristics. The presented realization also encompasses a new cavity design with improved temperature stabilization and assessment. This has contributed to an improved long-term characteristics of the GAMOR methodology. The system was characterized with respect to a dead weight piston gauge. It was found that for short integration times (up to 10 min) it can provide a response that exceeds that of the original SCM-GAMOR system by a factor of two. For integration times longer than this, and up to 18 hours, the system shows, for a pressure of 4303 Pa, an integration time independent Allan deviation of 1 mPa (corresponding to a precision, defined as twice the Allan deviation, of 0.5 ppm). This implies that the novel system shows a significant improvement with respect to the original realization of GAMOR for all integration times (by a factor of 8 for an integration time of 18 hours).When used for low pressures, it can provide a precision in the sub-mPa region; for the case with an evacuated measurement cavity, the system provided, up to ca. 40 measurement cycles (ca. 1.5 hours), a white-noise limited noise of 0.7 mPa (cycle) 1/2 , and minimum Allan deviation of 0.15 mPa. Furthermore, over the pressure range investigated, i.e. in the 2.8 -10.1 kPa range, it shows, with respect to a dead weight piston gauge, a purely linear response. This implies that the system can be used for transfer of calibration over large pressure ranges with exceptional low uncertainty.3

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Section: B Linearitymentioning

confidence: 94%

“…1, is based to a large degree on that for SCM-GAMOR. 28 28 The left out parts for arm 2 are identical to those of arm 1.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: A Scm-gamormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%