I’ve found this two interesting modules at Marzaglia ham radio flea market (11 May 2019) and bought for 5€.

ZP1210 geiger tube

Each module have soldered two geiger tubes, one per side and a signal conditioning/high voltage generator circuit.

The tubes are ZP1210 made by Valvo during 70’s I think. Valvo company doesn’t still exist but Centronic.co.uk still make this tube. It’s a design original made by Philips and made by various brands under licence.

ZP1210 gamma geiger tube
Lenght: 140mm
Plateau threshold: 400V
Plateau lenght: 100V
Plateau slope: 0.15%/V
Counting rate at 10e-2mGy/h: 110 count/s
Dead time: 200uS
Background shielded: 70 count/s
Dose rate range: 3x10e-4 / 10 mGy/h

The two modules

The onboard circuit seems in working order. I’ve tryied to feed it with  12/24/30V dc and obtained 160V across tubes with 30V input. I don’t know the correct voltage needed by it’s circuit. I don’t know how the circuit output it’s counting pulses. I’m thinking that this two modules are from a steel scrap radiation detection system. They probably are feed with a relatively high voltage like 48Vdc or 70Vdc and the output pulses from the tubes are used to modulate the power supply line. I’m thinking about scrapping the four tubes and as much as possible from the electronics but I’m not a fan of bit tru-hole components from the 70’s. With 5€ I’ve bought 4 very nice geiger tubes with very good characteristics… I’m very happy!

Top circuit
Did you have some info about it? There is a mark…


VEB Robotron 70013

This is the picture of the product from LCI electronics eBay listing

I’ve found this tube from an eBay seller called “LCI electronics”. He’s from Bulgaria. This tube was made in ex DDR, German Democratic Republic, in late 80′ from the well known manufacturer of hi-tech electronic products “VEB Robotron”. This pictures are of the item that I’ve received.

As you can see, the product that I’ve received is the same of that listed. Excellent package indeed! The seller sent me a brief datasheet/comparison chart and and application example.

MS-13 MC-13 glass tube

This tube is very hard to find. It’s compact size and it’s connection socket, similar to the car brake light bulb makes it the stangest tube I’ve ever seen.


There is very few information about it and it’s usage… it’s from the M-series of professional tubes so I could guess it was used in some kind of portable precision survey equipment.

MS-13 light bulb type base

It’s base looks very similar if not equal (I must try) as a car light bulb.

The tube and it’s datasheet

I don’t know russian so I just know how to recognize the most important parameters to make working the tube. I’ll appreciate more info’s about this tube, feel free to contact me at “l.i.papadopol at gmail.com”

-Working voltage 720-780V
-Plateau lenght 200V
-Plateau slope 0.15%
-Load resistance 8-15MOhm
-Working temperature -40° +50°
-Lenght 100mm diameter 21.5mm

MS-6 MC-6 γ-selective geiger counter

This is another glass russian Geiger tube made for professional use, not for military like all the M-series tubes. The MS-6 is gamma-selective and have a copper cathode. The internal wire is the anode and is made of platinum.

MS-6 tube

I’ve found two different but similar specs for this tube from two different eBay sellers

First eBay seller spec:

 ·         Radiation determine:   (γ) gamma soft/hard
 ·         Voltage of start of counting: 720 - 780V ;
 ·         Operating voltage (recommended): 820 - 880V;
 ·         Length of flat part of counting curve (plateau):  200 V
 ·         Slope of the counting curve:   < 0.1 %/V;
 ·         Sens. background:   < 120 counts/min;
 ·         Maximum radiation: 5*10e4 counts/min
 ·         Load resistance: 8 - 15  MOhm
 ·         Counter resistance: 4 - 8  MOhm
 ·         Allowable stray input capacitance: < 25 pF
 ·         Working temperature range: -40…+50 C
 ·         Anode material: Platinum (Pt)
 ·         Cathode material: Copper (Cu)
 ·         Dimensions: counter length 260mm, diameter 21.5mm

Second eBay seller spec:

Beginning of the counting voltage - 720V-780V.
The working voltage interval - 820V-880V.
The length of the plateau of the counting characteristics - not less than 200V.
The slope of the plateau of the counting characteristic - 0.1%/V.
The maximum count rate - 25000imp/min.
The biggest overload irradiation - 50000imp/min.
Sensitivity (when irradiated with 0.1 μR/s) - 4500imp/min-5500imp/min.
The largest background - 120imp/min.
Service life - 3∙108imp.
Temperature - from -40ºС to +50ºС.
Dimensions: diameter - 23mm  length - 266mm Weight - 65g


SI-19BG(M) си19бг-м mini Geiger tube

I’ve bought this cute mini Geiger tube from eBay. It’s cheap… in the order of 10-15€. The interesting thing about this tube is it’s size: 20mm lenght per 9mm diameter that makes it a good choice to make a portable dosimeter.

SI-19BG-M geiger tube

It’s sensibility is not hight but is better than SI-3BG. Another cool thing is it’s glass window. People around internet say that is a mica window for alpha particles but, I’ve testd it in contact with a piece of pechblende that, is a strong alpha+beta emitter sample and I’ve seen that it’s count rate is so small… like it ounts just beta+gamma.

SI-19BG window

Tech info:

  • Sensitivity: 1000-1500 Pulses/s/R/h
  • Plateau inclination: 0.25%/V
  • Working voltage: 360-440V
  • Maximum registering range: 900 Roentgen/hour
  • Lenght: 20mm
  • Diameter: 9.3mm
  • Weight: 4 grams

I’ve found on eBay a photo from a seller that sold it with it’s original connector… looks more an enclosure/socket than a connector.

SI-19BG connector

MST17 MCT17 Mica window Geiger tube

Searching for an alpha-sensible Geiger tube to buy, you’ll find for sure some Si8B and SBT11 pancale style tubes. This are great tubes but… if you found this MST17? It’s not a military surplus pancake tube, is from the professional series “M”. You must know that russian tubes that name starts with “M” are made for professional and scientific use. Usualy are made in glass and are fragile, they need higher voltage to operate but…. they are true scientific tools not cheap surplus!

MST17 Geiger tube

This is the MST17 tube, a professional tube used by russian in professional scientific equipment. Is cheaper than other mica windowed tubes because il hard to use. It need 1600V in order to operate. It was used to measure milk nuclear contamination after Cernobyl disaster in contamined ukrainian zones.

MST17 Front cap

The tube have a metal cap to protect the mica window and to filter out most od Alpha particles, i say “most” and not all because it have a small hole in the center. The mica window is not so thin so I think this tube is more suitable to beta and gamma use.

MST17 Mica window

I’ve found some other infos about this tube:

Tech. spec.:

  • Radiation determine: 
    1. Alpha *
    2. Beta (>0.16Mev)
    3. Gamma

*- the distance between source and mica window must be 25 mm or less (for alpha radiation only).

  • Voltage of start of counting: < 1600V
  • Operating voltage (recommended): 1620 – 1740V
  • Length of flat part of counting curve (plateau):  150 V
  • Slope of the counting curve:   < 0.05%
  • Own background:   < 0.41 counts/s
  • Maximum radiation: 10,000 counts/min
  • Load resistance: 7-10 MOhm
  • Allowable stray input capacitance: < 10 pF
  • Working temperature range: -30…+50 C
  • Anode material: Platinum
  • Mica window thickness: < 5 mg/cm2
  • Weight: ~20g
  • Dimensions: counter length 100mm, diameter 40mm
  • Mica window diameter: 20 mm.

DP100 milk dosimeter

The DP100 russian scientific instrument use the MST17, enclosed into a lead chamber to reduce background radiation, to mesure milk contamination.

CHERNOBYL ACCIDENT” there is a physical modelling and mathematical analysis of this device.

MSTR-4 MCTP-4 Alpha-Beta-Gamma geiger tube

This is a cool tube! The MSTR-4 is a mica end-window all glass geiger tube. Is so rare to find out there but once you can find one the problem is shipping, is so fragile! Is extremly sensible, the seller told me that it’s natural background is 25000CPM!!! I need to test it but… the trouble that it need 1200V to operate. Some photo and info sight down there on the page.

  • Working Voltage 1200V – 1350V
  • Plateau Length 200V Plateau Slope 5% / 100V
  • Interelectrode Capacitance 25pF
  • Load Resistance 8 – 15 MOhms
  • Working Temperature Range +5 +35 С
  • Length 180 mm
  • Diameter 35 mm

The MSTR-4 geiger tube with it’s datasheet

MSTR-4 view from back

Take care about the round electrodes. They could easily be detached from the glass if handled roughly. Don’t try to solder on it contacts or the glass will break. Use round clip from a PCB fuse holder.

MSTR-4 mica window

The mica window makes this tube to be very sensible. It can detect weak alpha rays too!

Stay tuned, I’ll try to feed his 1.2Kv needs and make a video of it @ work.

SI-22G CИ-22Г Geiger Muller tube

This tube is highly sensitive, similar to the STS-6, ideal to make a natural background monitoring equipment. It could be used also to make a personal dosimeter but it’s size is a limiting factor.

SI-22G tube

It’s characteristics:

  • Working Voltage: 360 – 440V
  • Initial Voltage: 285 – 335V
  • Recommended Operating Voltage: 400V
  • Plateau Length: 100V
  • Plateau Slope: 0.125% / 1V
  • Inherent counter background (cps): 1.16 Pulses/s
  • Cobalt-60 Pulse Gamma Sensitivity: 540 pulse/uR
  • Load Resistance: 9 – 13 MOhms
  • Working Temperature Range: -50 to +70С
  • Length: 220mm
  • Diameter: 19mm

SI3BG CИ-3БГ Geiger Muller Tube

I’ve bought this tube some time ago with other tubes from an ukrainian seller because of it’s price. Usualy it is sold at 2€ each. This tube is so small and cute but is… absolutely useless.

SI3BG russian geiger tube

If you try to measure the natural radioactivity or if you try to test barely radioactive samples like pechblende or uranium glass you’ll obtain CPM in the range of 4-5 for the natural background and 15-20 for a medium active pechblende sample.

Typical application circuit

It was made to test fallout from a nuclear explosion. I’ve seen is usen in russian personal counters to help other two SBM20 tubes when the situation is too hot. Practically, is just usefull for pocket counters/alarms for soldiers during a nuclear war.


STS-6 CTC-6 Geiger Muller Tube

Hi! I’ve just received two STS-6 Geiger Muller tubes from Ukraine. They are HUGE! Their size is 199mm long X 22mm diameter. In this video that I’ve made you can see I’ve enclosed in into a thick walled Alluminium pipe so I can filter out all beta’s and count just gamma’s. This because without it, my pechblende sample count more than 14500 CPM at 2cm from the probe. Uranium decay emit alpha + a lot of beta BUT…some of his impurities (radium) decay with gamma. I’m interested in gamma emitting sources.

The Uranium decay

This is the video:

And some more info about the tube and pics:


  • Working Voltage 390 – 400V
  • Initial Voltage 285 – 335V
  • Plateau Length 80V Plateau Slope 0.125% / 1V
  • Inherent counter background (cps) 1.83 Pulses/s
  • Interelectrode Capacitance 10pF
  • Load Resistance 5 – 10 MOhms
  • Working Temperature Range -500 +700 С
  • Length 199 mm
  • Diameter 22 mm

The STS-6 tube with it’s original box and datasheet. The screwdriver is for size comparison

This tube is so BIG!