FOR SALE lot of 1 pc.  STS-5 Geiger counter tube analog of  sbm-20 

All tubes are tested working well. New old stock.

STS-5 GM tube is analog of well-known SBM-20 GM tube, just older version. I added one photo to compare them. sts-5 is just 2mm longer than sbm-20

Parcel will be well packed and shipped by air mail with tracking number, shipping usually takes 12-21 days, depends on your location. 

If you need more tubes than listed or other type of devices please send me a message.

STS-5 Geiger Counter Tube Technical Specifications: 

⚙️ General Specifications

Parameter	Value
Tube Type	Geiger–Müller (GM)
Model	STS-5
Radiation Detected	Hard Beta & Gamma
Condition	NEW Old Stock, Tested
Gas Filling	Ne + Br₂ + Ar
Cathode Material	Stainless steel, 50 µm
Connector	Pin
Operating Temperature	−40 °C to +50 °C

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📐 Dimensions & Physical Characteristics

Parameter	Value
Maximum Length	108 / 101 mm
Effective Length	91.0 / 83.5 mm
Maximum Diameter	11 mm
Effective Diameter	10 mm
Tube Capacitance	10 pF
Weight	10 g

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🔌 Electrical Specifications

Parameter	Value
Minimum Anode Resistor	5.0 MΩ
Maximum Anode Resistor	10.0 MΩ
Recommended Operating Voltage	400 V
Operating Voltage Range	360 – 440 V
Initial Voltage	280 – 330 V
Plateau Length	≥ 80 V
Plateau Slope	0.125 % / V
Minimum Dead Time (400 V)	190 µs
Working Range	0.004 – 40 µR/s
Working Range	0.014 – 144 mR/h
Gamma Sensitivity (Ra-226)	29 cps / mR/h
Gamma Sensitivity (Co-60)	22 cps / mR/h
Maximum Natural Background	27 pulses/min
Expected Lifetime	≥ 2 × 10¹⁰ pulses

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✅ Features & Benefits

• ✔ Designed for hard beta and gamma radiation

• ✔ Stable plateau and low background count

• ✔ Long service life

• ✔ OLD STOCK, individually tested

• ✔ Ideal for Geiger counters, dosimeters, restoration, and collectors

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📦 What You Will Receive

• 1 × STS-5 Geiger Counter Tube

• Secure protective packaging

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🚚 Shipping & Handling

• Ships within 1–2 business days

• Carefully packed to prevent damage

• Worldwide shipping available

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🔁 Returns

Returns accepted if the item is not as described.
Please contact the seller before returning.