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lamaPLC: RadiationD Geiger counter module
The RadiationD-v1.1 is a popular DIY Geiger counter module for measuring ionising radiation, often paired with microcontrollers like the ESP32 or Arduino. It typically utilizes a Miller tube (Geiger-Müller tube) to detect gamma rays and some beta particles.
The RadiationD-v1.1 module’s measuring limits are primarily determined by the specific Geiger-Müller (GM) tube installed on the board. Most kits use either the J305 or M4011 glass tubes.
☢️ Radiation Type Limits
- Gamma (Γ): Excellent detection. It is most accurate for Gamma rays (like those from Cesium-137).
- Beta (β): Detects high-energy (“hard”) Beta particles. Low-energy Beta may not penetrate the glass tube wall.
- Alpha (α): Not detectable. The glass wall of the J305/M4011 tubes is too thick for Alpha particles to enter; they are blocked by the glass or even a few centimeters of air
RadiationD Recommended and Compatible Tubes
The RadiationD-v1.1 (also known as the CAJOE module) is highly versatile and supports most Geiger-Müller (GM) tubes that operate with an anode voltage between 350V and 500V.
| Parameter | J305 | J321 | M4011 | SBM-20 | STS-5 | LND-712 |
|---|---|---|---|---|---|---|
| Material | Glass | Glass | Glass | Metal (Stainless) | Metal (Stainless) | Metal / Mica Window |
| Sensitivity | Moderate | Low-Moderate | Moderate | High | High | Very High |
| Alpha | No | No | No | No | No | Yes (via window) |
| Beta | Yes (High energy) | Yes (High energy) | Yes (High energy) | Yes (Excellent) | Yes (Excellent) | Yes (Excellent) |
| Gamma | Yes | Yes | Yes | Yes | Yes | Yes |
| Dose Limit | ~1.2 mSv/h | ~1.0 mSv/h | ~1.2 mSv/h | ~1.44 mSv/h | ~1.44 mSv/h | ~2.0 mSv/h |
| Op. Voltage | 350V - 450V | 350V - 450V | 350V - 450V | 350V - 475V | 350V - 475V | 450V - 500V |
| Light Sens. | High (Needs tape) | High (Needs tape) | High (Needs tape) | None | None | None |
| Notes | Standard DIY tube; very fragile. | Similar to J305; often shorter. | Very common in Chinese kits. | Industry standard; very durable. | Soviet version of SBM-20; longer. | Professional; detects all types. |
The Glass Tubes (J305, J321, M4011)
- Light Sensitivity: These act like solar cells. If you don't wrap them in black tape or put them in a dark box, the sun will cause thousands of “fake” counts.
- Beta Detection: They can only detect “hard” Beta. The glass walls are too thick for Beta particles to penetrate.
The Soviet Workhorses (SBM-20, STS-5)
- Durability: These are metal tubes. They won't break if you drop them, and they are completely immune to light interference.
- Size: The STS-5 is longer than the SBM-20. Neither usually fits the standard “clips” on the RadiationD board without modification or the use of wires.
The Professional Choice (LND-712)
- Alpha Detection: This is the only tube on your list with a Mica end-window. This window is thin enough to let Alpha particles through.
- Voltage: It requires the higher end of the RadiationD's power range (near 500V). You must adjust the blue potentiometer (P1) while measuring the voltage with a high-impedance multimeter.