A LOW COST METHOD FOR ENVIRONMENTAL TESTING AT CRYOGENIC TEMPERATURES

A LOW COST METHOD FOR ENVIRONMENTAL TESTING AT CRYOGENIC TEMPERATURES

Testing electronics at cryogenic temperatures requires special equipment

Paul AndersonUniversity of Idaho

April 19, 2023 Paul Anderson 2

Overview

Why Create a Cryogenic Testing Chamber? Requirements Low Cost Chamber Low Cost Chamber Control Test Results Improvements to the Design Does the Chamber Meet the Requirements? Conclusion / Recommendations


Why Create a Cryogenic Testing Chamber?

University of Idaho’s Microelectronics Research and Communications Institute (MRCI) recognized a need for a low-cost cryogenic temperature environmental chamber for the development and testing of electronics over a wide temperature range.


Requirements

Portable: One person can move the chamber Efficient: It must use less than one standard

transfer cylinder of liquid nitrogen for one 8 hour test

Capable of any temperature below room temperature to -180°C

Safe Automated real-time temperature monitoring Easy to use for MRCI personnel with a short

training period Adaptable to any type of package pin configuration Low-cost: less than $5,000


Low Cost Chamber

Aluminum cylinder with removable top

4 thermocouples 2-64pin sockets 4 D-Sub connectors for

connection of test signals GN2 gas purge for water

abatement ½ inch lines for liquid

nitrogen input and exhaust of gas out of the chamber


Low Cost Chamber

Liquid Nitrogen supply is from a standard 180L transfer cylinder pulsed into the chamber through a cryogenic solenoid valve

The system is controlled with bench top instruments, GPIB architecture, and NI LabVIEW


Low Cost Chamber Control

LabVIEW Program Controls the

temperature in the chamber

Shows real-time temperature of the chamber

Saves the temperature data to file


Test Results-

Reached -190°C 5°C ripple around

the set point Initial Overshoot of

desired temperatures

5°C ripple


Improvements

Spray Bar New Lid Change in

Thermocouples DAQ Integration Future Improvements?


Improvements: Spray Bar

Capped brass pipe with 18 holes drilled into the walls of the pipe

Adaptor made to allow the use if pipes

Injects LN2 more uniformly into the chamber

Restricts flow of LN2


Improvements: Spray Bar

Results: Less Ripple

1C instead of 5C Removed micro-

pulsing of valve, reducing valve wear

Cost: $100, Parts and

labor


Improvements: New Lid

Screw-on lid damaged during a test

New lid designed for ease of use

New Lid design can be opened faster than old lid could

Easily repairable: if threads on bolts are damaged, old bolts my be cut off and replaced


Improvements: New Lid

Easily repairable: if threads on bolts are damaged, old bolts my be cut off and replaced

Cost: Approximately the same as previous lid


Improvements: Thermocouples

Change from K-Type Thermocouples to E-Type Thermocouples K-Type: 0.75% Error E-Type: 0.5% Error

Cost Difference Negligible


Improvements: DAQ Integration

NI PXI-6289 DAQ system with embedded controller

Interface with NI SCB-68 shielded thermocouple terminal block



Four Thermocouples sense the temperature inside the chamber

The voltage of each thermocouple measured by four input channels on the NI PXI-6289 DAQ system, coupled with the NI SCB-68 Connector Block.

Benefits: more accurate than a

system using DMMs faster than a system using

DMMs


Final Cost of Materials

Item Cost

Materials for Chamber $350.00

Plumbing supplies $1,700.00

Cryogenic valve $200.00

Miscellaneous $50.00

Total $2,300.00*

*Not including DAQ, DMM, LabVIEW license, or other MRCI equipment. Some Assembly Required Not responsible for injury or death. If you are reading this, I must be really boring.


Does the Chamber Meet All the Requirements? Yes!

Portable One person can move the chamber

Efficient Two or more tests on one 180L transfer cylinder of

liquid nitrogen Low temperature of -196°C possible Safe

Fails to a safe condition Automated

LabVIEW controlled with real-time monitoring Easy to use with only a brief training period Adaptable to any package configuration Low cost

$2,300 for chamber materials


Acknowledgments

Dr. Herb Hess - University of Idaho Tracey Windley - University of Idaho Matthew Braley – University of Idaho Kevin Buck - University of Idaho Dr. Mohammad Mojarradi - JPL Scott Cozy - JPL NASA Jet Propulsion Laboratory NASA EPSCoR


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A LOW COST METHOD FOR ENVIRONMENTAL TESTING AT CRYOGENIC TEMPERATURES

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