Sample Throughput Optimization for
Thermal Desorption Spectroscopy
Ethan Greene, Jamie Lee, Saul Rios, Leo Serbinov, Vedanth Talla, Brayden Wong
Department of Mechanical and Aerospace Engineering at University of California San Diego
Sponsored by PISCES Lab
Scan this QR code to visit the team website! Includes CAD, videos, reports, and project management
Final Design
- Tests 8 samples in 1 work day
- Divided into two sections divided by a gate valve:
- Sample Loading Chamber
- Sample Testing Chamber
- Grabber moves samples within system
- Three actuators
- Sample Transporter: Provides linear motion and opening and closing of the grabber
- Storage Actuator: Provides vertical motion for a sample storage elevator
- Thermocouple Actuator: Moves thermocouple wire on and off of the sample
Overview
This project, as sponsored by the PISCES Lab within UC San Diego’s Center for Energy Research, focuses on the development of a sample loading system for a thermal desorption spectroscopy (TDS) system. TDS occurs at ultra high vacuum pressures (1.33*10-7 Pa) and at samples are heated to 1100 ℃.
Primary Objective: Increase the throughput of samples tested each workday by developing a sample loading system that can exchange samples in vacuum conditions.
Functional Requirements
- Ability to test at least 5 samples in one day
- Chamber remains at vacuum pressures during sample exchange and testing
- All materials are resistant to outgassing
- Thermocouple is in contact with sample during testing
Hardware Testing
Testing Performance
- System was tested with acrylic models in place of quartz pieces and a temporary, shorter sample transporter due to long lead times
- Grabber is effectively able to move linearly and open and close using the sample transporter
- Temporary sample transporter had weak magnetic coupling making it difficult to extend grabber at times
- Sample loading process takes ~15 minutes
- With TDS testing taking 1 hour per sample, the system is able to test 8 samples within a 10 hour period
- Increases sample throughput by a factor of 8
Components
Sample Holder
- Fused Quartz
- Allows for sample faces to remain
untouched by grabber
- Can be manufactured for different
sample sizes
- Adjust hole size or shape
Grabber
- 304 Stainless Steel
- Forklift design
- Attaches to 2 DOF actuator
- Linear movement
- Rotational DOF: opens and
closes grabber
Elevator
- 304 Stainless Steel
- Modular Design
- 8 sample holder slots
Sample Pedestal
- Fused Quartz
- Holds sample holder in place during
TDS testing
- Located in sample testing chamber
Thermocouple Attachment
- 304 Stainless Steel
- Grabs onto thermocouple wire
- Attached to thermocouple actuator
- Allows for thermocouple wire to
move on and off of sample
Sample Testing Chamber
- Fused Quartz & Borosilicate
Glass
Future Improvements
- Fully autonomous sample loading process
- Utilize motorized actuators
- Thicker thermocouple wire
- Increased rigidity, easier to manipulate
Impact on Society
- Research from the TDS system is conducted as part of a multinational project: ITER
- ITER is developing the world’s largest Tokamak
- PISCES analyzes wall materials of Tokamaks to improve the material performance and longevity
- ITER aims to produce the world’s first nuclear fusion power producing energy system
- Reduce reliance on carbon energy
- Mitigate climate change
Acknowledgements
- PISCES Lab at UC San Diego
- Simon Moore and George Tynan
- Professor Jerry Tustaniwskyj
- Thomas Chalfant and Chris Cassidy
Figure 1: CAD Assembly of Sample Loading System
Sample Exchange System
Figure 9: CAD of Grabber and Sample Storage Unit
Figure 2: CAD of Sample Holder
Figure 5: CAD of Sample Pedestal
Figure 6: CAD of Thermocouple Attachment
Figure 4: CAD of Sample Elevator
Figure 10: CAD of Grabber and Sample Pedestal
Figure 15: ITER’s Tokamak [1]
Figure 7: Render of Sample Testing Chamber
Thermal Analysis
- Testing chamber is made from quartz to withstand 1100 ℃ temperatures
- Must transition to glass to connect to CF Flanges, glass has a lower temperature range. Must transition materials 0.126 m from heater.
Figure 8: Ansys Thermal Analysis of Sample Testing Chamber
Figure 11: Final Assembly
Figure 13: Stainless Steel Grabber
Figure 14: Acrylic Models of the Sample Holders and Sample Pedestal
Figure 12: Final Elevator