Project Overview

Cryogenic cooling below 1 K requires special devices that use thermodynamic cycles that cannot operate at room temperature. In order to keep these devices cool, an adiabatic demagnetization refrigerator (ADR) is used. The ADR is composed of a solid salt crystal and a strong magnetic field. If the strength of the field is decreased, the thermal motion of the molecules twists them out of alignment. The thermal energy is transformed into magnetic energy, cooling the salt pill. When the ADR is combined with a cryostat filled with liquid helium, the device can go down to almost 0 K. This heat switch must cool the detector and then mechanically disconnect before flight. A prototype was previously designed and nearly ready for testing but was not completed due to COVID-19 shutting down the cryogenics lab.

The goals of this project are to iterate the design of the previous team’s prototype and identify opportunities to incorporate a mechanical actuation heat switch that will disconnect before flight. The expected end result is a functional and tested prototype that will thermally disconnect the ADR from the bath to allow the thermodynamic cycle to proceed before flight. The resulting design and prototype must fit and operate in an existing cylindrical envelope of a rocket payload and the Center for Detector’s (CfD) cryostat. In addition to this the prototype must be non-magnetic, able to endure temperatures of 77 K while testing, 4 K in flight, and operate in a vacuum. The prototype must be well designed, undergoing 1,000 operation cycles and sustaining the simulated vibrations that occur in a rocket launch. Four manuals must also be produced including how to train operators, maintain the device, service the device, and for flight operations.   

The finished prototype operated well and cryogenic temperatures and passed all vibration testing. Work needs to be completed to improve the heat transfer rate to meet customer requirements. New arms have been designed and will be handed off to the customer. These new arms are expected to increase the heat transfer rate from the original arms. The 1,000 lifetime cycle test was stopped prematurely due to a flex pivot failure. This occurred about 150 actuations in and the team felt comfortable this specification would have been met without the failure. Fortunately the flex pivots would have had to been replaced anyway for the new arms. The new arms should complete this prototype and improve its ability.

Project Title: Flight-Ready Heat Switch for Deep Cryogenic Applications

Project Number: P21129

Project Family: Heat Switch

Start Term: 2201 Fall Semester 2020

End Term: 2205 Spring Semester 2021

Faculty Guide: William Nowak

Primary Customer: Dr. Mike Zemcov

Sponsor (financial support): Center for Detectors

Planning & Execution

Project Photos and Videos

Imagine RIT

Gate Reviews

Problem Definition

Systems Design

Preliminary Detailed Design

Detailed Design

Build & Test Prep

Subsystem Build & Test

Integrated System Build & Test

Customer Handoff & Final Project Documentation (Verification & Validation)

PRP

Requirements

Schedule

Cost

Risk Management

Communication & Minutes

Use Cases

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Functional Decomposition

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BOM

Mechanical Drawings

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Manuals

Prototyping

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Poster

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