CosmicWatch: The Desktop Muon Detector(v3X)

TL;DR

The paper presents the CosmicWatch Desktop Muon Detector v3X, a compact, low-cost detector designed for education and introductory research in particle physics. It details hardware and firmware upgrades—improved analog electronics, a dual-core MCU architecture, onboard sensors, and robust data logging with OLED, SD card, and USB interfaces—that enable high-rate, coincident-triggered muon measurements. Demonstrated measurements include full-sky muon flux, angular dependence following a cos^2 law, high-altitude radiation profiling, and muon time-of-flight velocities, illustrating the detector’s scientific and educational potential. The work emphasizes accessibility and adaptability, aiming to support citizen science networks and classroom experiments through modular design and extensive documentation.

Abstract

The CosmicWatch Desktop Muon Detector (v3X) is a compact, low-cost, and portable device designed for detecting ionizing radiation, including cosmic-ray muons. Building on previous iterations, the v3X introduces significant hardware and firmware improvements that enhance sensitivity, usability, and data acquisition capabilities. The detector integrates a plastic scintillator and silicon photomultiplier (SiPM), custom designed electronics for signal processing, onboard data storage, OLED display, environmental sensors, and USB connectivity. With a total component cost under \$100 and a build time suitable for high school students, the v3X is ideal for education, outreach, and introductory research applications in particle and astroparticle physics. This paper details the design, performance, and potential use cases of the v3X, supported by example measurements demonstrating its functionality.

Figures (17)

• Figure 1: An array of the CosmicWatch Desktop Muon Detectors v3X. The front and rear faceplates provide access to the SiPM output, microSD card slot, microUSB connection, and coincidence ports. Additional elements include an OLED display, reset button, trigger LED, and coincidence LED.
• Figure 2: Block diagram of the main board. The analog section shows the amplification, peak detection, as well as the comparator. The digital section illustrates the communication between peripherals as well as monitors and controls.
• Figure 3: A rendering of the top and bottom sides of the SiPM PCB mounted to the plastic scintillator with four 3/8" #2 screws.
• Figure 4: Rendering of the top and bottom of the main PCB.
• Figure 5: The SiPM and main PCB assembly.