Thermal and Structural Analysis of a Suspended Physics Package for a Chip-Scale Atomic ClockSource: Journal of Electronic Packaging:;2009:;volume( 131 ):;issue: 004::page 41005DOI: 10.1115/1.4000211Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: The power dissipation for chip-scale atomic clocks (CSAC) is one of the major design considerations. 12 mW of the 30 mW power budget is for temperature control of the vertical-cavity-surface-emitting laser (VCSEL) and the alkali-metal vapor cell. Each of these must be maintained at 70+/−0.1°C even over large ambient temperature variations of 0–50°C. Thus the physics package of a CSAC device, which contains the vapor cell, VCSEL, and optical components, must have a very high thermal resistance, greater than 5.83°C/m W, to operate in 0°C ambient temperatures while dissipating less than 12 mW of power for heating. To create such a high level of insulation, the physics package is enclosed in a gold coated vacuum package and is suspended on a specially designed structure made from Cirlex, a type of polyimide. The thermal performance of the suspended physics package has been evaluated by measuring the total thermal resistance from a mockup package with and without an enclosure. Without an enclosure, the thermal resistance was found to be 1.07°C/m W. With the enclosure, the resistance increases to 1.71°C/m W. These two cases were modeled using finite element analysis (FEA), the results of which were found to match well with experimental measurements. A FEA model of the real design of the enclosed and suspended physics package was then modeled and was found to have a thermal resistance of 6.28°C/m W, which meets the project requirements of greater than 5.83°C/m W. The structural performance of the physics package was measured by shock-testing, a physics package mockup and recording the response with a high-speed video camera. The shock tests were modeled using dynamic FEA and were found to match well with the displacement measurements. A FEA model of the final design, not the mockup, of the physics package was created and was used to predict that the physics package will survive a 1800 g shock of any duration in any direction without exceeding the Cirlex yield stress of 49 MPa. In addition, the package will survive a 10,000 g shock of any duration in any direction without exceeding the Cirlex tensile stress of 229 MPa.
keyword(s): Physics , Design , Temperature , Atomic clocks , Shock (Mechanics) AND Structural analysis ,
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contributor author | A. D. Laws | |
contributor author | R. Borwick | |
contributor author | Y. C. Lee | |
contributor author | P. Stupar | |
contributor author | J. DeNatale | |
date accessioned | 2017-05-09T00:32:16Z | |
date available | 2017-05-09T00:32:16Z | |
date copyright | December, 2009 | |
date issued | 2009 | |
identifier issn | 1528-9044 | |
identifier other | JEPAE4-26300#041005_1.pdf | |
identifier uri | http://yetl.yabesh.ir/yetl/handle/yetl/140269 | |
description abstract | The power dissipation for chip-scale atomic clocks (CSAC) is one of the major design considerations. 12 mW of the 30 mW power budget is for temperature control of the vertical-cavity-surface-emitting laser (VCSEL) and the alkali-metal vapor cell. Each of these must be maintained at 70+/−0.1°C even over large ambient temperature variations of 0–50°C. Thus the physics package of a CSAC device, which contains the vapor cell, VCSEL, and optical components, must have a very high thermal resistance, greater than 5.83°C/m W, to operate in 0°C ambient temperatures while dissipating less than 12 mW of power for heating. To create such a high level of insulation, the physics package is enclosed in a gold coated vacuum package and is suspended on a specially designed structure made from Cirlex, a type of polyimide. The thermal performance of the suspended physics package has been evaluated by measuring the total thermal resistance from a mockup package with and without an enclosure. Without an enclosure, the thermal resistance was found to be 1.07°C/m W. With the enclosure, the resistance increases to 1.71°C/m W. These two cases were modeled using finite element analysis (FEA), the results of which were found to match well with experimental measurements. A FEA model of the real design of the enclosed and suspended physics package was then modeled and was found to have a thermal resistance of 6.28°C/m W, which meets the project requirements of greater than 5.83°C/m W. The structural performance of the physics package was measured by shock-testing, a physics package mockup and recording the response with a high-speed video camera. The shock tests were modeled using dynamic FEA and were found to match well with the displacement measurements. A FEA model of the final design, not the mockup, of the physics package was created and was used to predict that the physics package will survive a 1800 g shock of any duration in any direction without exceeding the Cirlex yield stress of 49 MPa. In addition, the package will survive a 10,000 g shock of any duration in any direction without exceeding the Cirlex tensile stress of 229 MPa. | |
publisher | The American Society of Mechanical Engineers (ASME) | |
title | Thermal and Structural Analysis of a Suspended Physics Package for a Chip-Scale Atomic Clock | |
type | Journal Paper | |
journal volume | 131 | |
journal issue | 4 | |
journal title | Journal of Electronic Packaging | |
identifier doi | 10.1115/1.4000211 | |
journal fristpage | 41005 | |
identifier eissn | 1043-7398 | |
keywords | Physics | |
keywords | Design | |
keywords | Temperature | |
keywords | Atomic clocks | |
keywords | Shock (Mechanics) AND Structural analysis | |
tree | Journal of Electronic Packaging:;2009:;volume( 131 ):;issue: 004 | |
contenttype | Fulltext |