Design Components

RadiCal's final design is composed of 4 distinct subsystems: Chamber, Windmill, Aperture, and Electronics. Each component has gone through extensive design and testing to provide a compact, efficient product that can achieve the necessary goals and beyond.

Furthermore, various components within RadiCal have been designed with total modularity in mind, both for easy integration and future servicing and repair. This means that components can be removed with screwdrivers, Allen keys, or even just human hands.

Take a look at our subsystems below!

Chamber

Our chamber is the structure into which all the other subsystems fit, and it is also the primary shielding object. Composed of a hot-rolled steel outer layer and a lead inner layer that are bolted together, the chamber has been precision-manufactured to ensure that radiation on all sides has reached TVL attenuation.

For ease of portability and transportation, the chamber also features three handles welded to the outer steel walls, two on the side and one on the top.

Steel Outer Layer

Lead Inner Layer

Close-up of rabbet joint connection and design

To ensure that the chamber can not only attenuate on the walls, but also on the corners of the chamber, we have employed a rabbet joint connection within the inner lead layer.

This joint style ensures that gamma radiation emanated from the sources does not travel through corner seams, thereby ensuring the utmost safety during operation.

Windmill

Our rotational mechanism, dubbed the "Windmill Mechanism", doubles as a source holder and a way to mimic dosage rates through attachment to a NEMA 17 stepper motor.

The windmill is comprised of two parts, the lid and the base, and snaps together using neodymium magnets of reverse polarity. It can fit a total of four sources onto our mechanism, two disks and two capsules, allowing for increased calibration capabilities and source selection.

The windmill is coupled to the stepper motor, which rests on a custom motor stand that is bolted to the base of the chamber.

Complete Windmill Mechanism

Motor & Motor Stand

Windmill Components and Features

Front of Lid
Extruded numbers allow for source selection within our mobile application.

Back of Lid
Magnets are glued onto the pylons sticking out of the lid.

Front of Base
Sources can be placed into the holes and easily removed with tweezers. Four smaller holes also allow for magnets to be glued into.

Back of Base
A small motor hub extrusion allows for the insertion of the stepper motor shaft, with a hole on top to couple the motor to the windmill via a set screw. Another small extrusion enables the integration of a larger magnet, used for hall-effect sensor calibration.

Position of Windmill within Chamber

Aperture

Our aperture mechanism is a simple assembly, composed of two ACTOCAT linear actuators that move a 3D printed door piece that has a small tungsten cube embedded into it, allowing it to emanate radiation when open, but shielded to TVL levels when closed.

This aperture can be remotely controlled via Bluetooth signals, allowing for application-based control of open and closing motions.

Aperture Assembly

Aperture Components

Door Piece

3D printed piece that possesses a hole for placement of the tungsten block and two handles to couple actuators to.

Tungsten Cube

A standard tungsten cube that slots into the door piece. It's thickness complies with the TVL value for tungsten, shielding radiation when RadiCal is not in use.

Position of Aperture within Chamber

Electronics

Our electronics system acts as the brain of the entire operation and is where components like our actuators, motor, and battery connect.

For a professional, compact project, we integrated our electronics onto a KiCAD-designed PCB, reducing clutter from jumper wires and other cables.

Bluetooth capability is integrated through our choice of microcontroller, the ESP32, which can be controlled via a mobile application.

PCB Schematic Capture

Circuit Hardware-in-Loop Setup

PCB and Electronic Components

Stepper Motor
Precision control motor that can spin to high RPMs and enable single-source selection.

Linear Actuator
Enables smooth, continuous motion of the aperture.

ESP32 Microcontroller
Robust microcontroller that possesses an antenna for Bluetooth and Wi-Fi integration.

Stepper Motor Driver
Controls the movement of the stepper motor through precise micro-stepping and voltage intervals.

Linear Actuator Driver
Controls the movement of the linear actuators through PWM modulation

Hall Effect Sensor
Measures magnetic force, allowing for single-source selection via detection of a magnet on the back of the windmill.

Voltage Regulator
Steps down 12V battery connection to 3.3V to conserve energy and enable longer battery life.

Page updated

Report abuse