For many citizens and students interested in particle physics and astrophysics, there are few opportunities to touch real research that needs expensive equipment such as an accelerator, a telescope, and a detector. However, recent technological developments have made it possible to build a low-cost detector, and some physicists have tried to develop simple detectors for outreach and education.
We have also designed and developed a low-cost and compact detector, OSECHI (Outreach \& Science Education Cosmic-ray Hunting Instrument), that can measure cosmic-ray muons. The detector consists of three 3D-printed plastic scintillator layers that can measure coincident events by one detector. Silicon photomultipliers (SiPMs) are mounted on the scintillators for light collection. Output signals from SiPMs are read by a custom-designed electronics board which records the charge and timing information of the signals. Three LEDs corresponding to three scintillators are implemented on the board, and we can check the signals by eye in real time. The board can be powered by a USB connector and has the DC-HV converter to provide the bias voltage to the SiPMs. Some interfaces are implemented in which commercial monitors such as thermometers and GPS can be added. The functionalities for all signal processing are controlled by a chip microcontroller. All the parts of the detector are contained in the Japanese-style tiered bento box, “Jubako”.
In this paper, we introduce the details of the OSECHI and the performance of the prototype. Examples of its use of outreach will also be reported.