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Remotely Actuated Radiation Calibration System
University of California, San Diego
Department of Mechanical and Aerospace Engineering
MAE 156B: Senior Design Project (Spring 2026)
Background
Background
The Department of Radiation and Medicine Sciences (RMAS) employs radioactive devices and materials to treat patients with cancer and researches radiation therapies and patient care techniques.
Our sponsor, Dr. Dan Scanderbeg, specializes in brachytherapy. To research the properties of radioactive materials as well as calibrate radiation equipment effectively, Dr. Scanderbeg commonly creates custom engineering equipment to advance the capabilities of radiation medicine.
Problem Definition
Problem Definition
Over 300 Geiger counters across the various research labs in UC San Diego require annual calibration to ensure accurate and consistent readings of radiation. The procedure is composed of placing Cesium-137, a well-characterized radioactive isotope, into a shielded chamber at a fixed distance from the Geiger counter. An operator then opens an aperture in the chamber to allow for radiation to permeate while calibration occurs; the aperture is then closed once calibration is finished.
Diagram of typical calibration setup
Limitations and Problems
Limitations and Problems
The current calibration chamber, however, has many limitations and risks. These include:
Fully manual operation, and thus close exposure to radiation
Uncomplicance with ALARA (As Low as Reasonably Achievable) radiation standards
Calibration of only one source at a time
No functionality to simulate varying dosage rates of radiation
Thus, our goal is to design a new chamber that can accommodate the shortcomings of the current chamber while adding new functionalities for expert calibration purposes.
Current Chamber
Our Solution
Our Solution
Based off the limitations and the risks of the current hardware and test setup, our solution must encompass the following deliverables as provided by our sponsor for a successful, extremely robust, and safe product.
Primary Objectives
Achieve 1 TVL* of radiation attenuation on all sides of the chamber
Fully remotely actuated electronics via WiFi or Bluetooth
Total assembly weight limit of 80 lbs
Ability to hold more than one radiation source within the chamber
Secondary Objectives
Portable and easy to transport across campus
Battery-powered electronics with rechargeable capabilities
Modular internal components for hassle-free assembly and repair
WOW Solution Objectives
Ability to hold more than 2 radiation sources of various form factors (disk and capsule sources)
Internal rotational mechanism to simulate variable dosage rates, up to 100 RPM
*TVL (Tenth-Value-Layer) is a radiation variable that indicates the thickness of material needed to attenuate 90% of incoming radiation.
Final Design Summary
Final Design Summary
Picture of Chamber
CAD Render of Chamber Assembly
Our project can....
Simulate dosage rates via an internal mechanism up to 100 RPM
Carry a total of 4 sources of both disk and capsule shapes
Be fully remotely actuated via a mobile application
Be easily recharged through a removable battery cell
Achieve more than 1 TVL attenuation on all sides
Be easily carried around and serviced through modulus components
Design Overview Video
Design Overview Video
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