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Connect SBT10A tube / Anschluss Zählrohr

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cmug

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Beiträge: 2

Registriert: Mi 10. Aug 2016, 12:37

Beitrag Mi 10. Aug 2016, 12:41

Connect SBT10A tube / Anschluss Zählrohr

Hello . . . (If hoffe Sie können die Englische Sprache lesen.)
I’am an starter hobbyist and like to measure small amount of ionizing radiation.
I already build an simple counter with the SI8-B tube for Beta and gamma
I did an order for the SBT10A tube today. To measure better Alpha particles.
I try to read the specification sheet (I found on pripyat website).
But I can’t read Russian language.
I looked for an circuit online, how connect this tube but did found only 1 website.
How should I connect this tube to my counter ?
I bought as counter the High Voltage Geiger Probe Driver from rhelectronics.

The Kathode (Minus) is High Voltage Geiger Probe Driver connect to the earth, that seems not the problem.
But the Anode (+) ? Should I just parallel connect them ? (I saw that on a photo on Ebay)
or
Should I give every single Anode an 10 MΩ resistor and then connect them ?
Like this: http://shaddack.brutowave.com/projects/ ... akeGeiger/

Already thank you for your tips and greetings from Netherlands:
<<

jsbid

Moderator
Moderator

Beiträge: 234

Registriert: Fr 26. Jul 2013, 07:42

Beitrag Do 18. Aug 2016, 20:15

Re: Connect SBT10A tube / Anschluss Zählrohr

cmug hat geschrieben:I try to read the specification sheet (I found on pripyat website).
But I can’t read Russian language.

Well, you can simply enter сбт10а into google and it will happily
find some russian website with some data which can be pasted
into google translator. The result will look like:

  Code:
Specifications appliances Geiger-Mueller SBT-10A:
 
    The source of radiation - Cs;
    Sensitivity to gamma radiation:
    EDR - 4,0mkR ∙ s-1;
    362,5mkR 40mkR 1 ± 1;
    1450,0s ± 1 160s-1;
    Rated operating voltage of the device Geiger-Muller counter SBT-10A - 400V;
    Voltage beginning bills - 260V-320V;
    Slowness counting response - not less than 80V;
    The slope of the counting response - no more than 0.3% / V;
    Maximum working EDR - 6500c-1, 30mkR ∙ s-1 to n.. ± 20%;
    The maximum permissible dose rate - 300R ∙ h-1;
    Dimensions - 70h91h38mm;
    Weight of the device Geiger-Muller counter SBT-10A - 150g.


I looked for an circuit online, how connect this tube but did found only 1 website.
How should I connect this tube to my counter ?
I bought as counter the High Voltage Geiger Probe Driver from rhelectronics.

Don't know this thing but judging from its website it starts at 420 V while
the SBT10A apparently likes to see 400 V. I have no experience with the
SBT10A but it should be OK with 420 V. It probably won't blow off but it
might hurt its life expectancy slighlty. Best would be to dim the source
down to some 390 V...

The Kathode (Minus) is High Voltage Geiger Probe Driver connect to the earth, that seems not the problem.
But the Anode (+) ? Should I just parallel connect them ? (I saw that on a photo on Ebay)
or
Should I give every single Anode an 10 MΩ resistor and then connect them ?
Like this: http://shaddack.brutowave.com/projects/ ... akeGeiger/

Well, this depends on the detection circuit of the rhelectronics board. If it
grabs the pulses from the tube's cathode (as shown on your pancake
geiger link), you will be happy by connecting it the same way.

NEVER COMBINE THE ANODES TOGETHER DIRECTLY AND WITHOUT
INDIVIDUAL RESISTORS!

This will impose a noteworthy capacitive load which will be discharged
entirely for each pulse and puts a somewhat high burden onto the tube.
Same applies for the wires between the resistor(s) and the anode(s):
Always keep them as short as possible.

But if I look at

http://www.rhelectronics.net/store/medi ... -probe.JPG

it seems that the tube's cathode is connected to the system's ground
and they are detecting the pulses on the anode's end. We have just
learned that you should not combine all the anodes without their
individual resistors (see above). But if you connect the anodes as
they should be and attach the "virtual" common anode to the
rhelectronics thingie, you will probably lose too much of the pulse
to be detected properly. You just have to try...

One first step might be to connect just one anode (without a
resistor) and keep the others floating. If it counts it is good and
you're on the right path but beware that you will lose approx.
90% of all events (as only one anode is connected).

Next would be to check how the anode detection is implemented
in the rhelectronics board. If it's the standard version (resistive
voltage divider with a capacitor attached to the tap) we might try
to remove the anode's end resistor and replace it by the virtual
common anode from above. But this is all wild guessing -- it
would help a lot if we had some schematics (at least for the
detection circuit) of the rhelectronics board...
<<

cmug

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Beiträge: 2

Registriert: Mi 10. Aug 2016, 12:37

Beitrag Fr 26. Aug 2016, 23:48

Re: Connect SBT10A tube / Anschluss Zählrohr

Thanks you for your detailed reply. Today the sensor came with the mail.
If I connect one or more sections to the MyGeiger Dosimeter the meter works OK (it counts).

It takes more time to remove the 4M7 resistor on the print-board and the solder 10 external resistor so that I can determine if each anode get an ‘personal’ 4M7 (10M) resistor the counter provides better sensitivity.

The circuit for MyGeiger Dosimeter from rhelectronics is online in the PDF on Page 12
https://www.dropbox.com/s/6exmo8df26aui ... t.pdf?dl=1

The pulses are measured in the kathode side of the tube.
<<

jsbid

Moderator
Moderator

Beiträge: 234

Registriert: Fr 26. Jul 2013, 07:42

Beitrag Sa 27. Aug 2016, 08:50

Re: Connect SBT10A tube / Anschluss Zählrohr

cmug hat geschrieben:The pulses are measured in the kathode side of the tube.

Yes, so you are lucky. Apparently the anode is only used for this "external
probe enclosure"...

It takes more time to remove the 4M7 resistor on the print-board and the solder 10 external resistor so that I can determine if each anode get an ‘personal’ 4M7 (10M) resistor the counter provides better sensitivity.

Giving each anode its own resistor is primarily not for sensitivity reasons.
As I wrote this is needed to not ruin the tube prematurely. Of course, you
_CAN_ combine all anodes together directly -- this way, when one anode
triggers, it simply discharges all others as well. But this will stress the
discharging anode (as there are 10 anodes to discharge instead just one).
Yes, it will also reduce (just a bit) of sensitivity as all anodes can't count
when one has just triggered (and discharged all others). But this probably
won't be noticed under background conditions.

When picking the resistors be sure to use the correct ones. If I look at R22
on page 9 of your PDF it seems that they use a standard resistor. This is
crap. It should be capable of withstanding 500+ Volts. In the current GS,
which uses THT resistors, I used the Vishay VR25 series, e.g:

http://uk.rs-online.com/web/p/through-h ... s/4844545/

The new version will probably have SMD resistors from the Vishay MMB
0207 Series, e.g.:

http://de.farnell.com/vishay/mmb0207mc4 ... dp/2471820

But I would suggest that you get the THT version and solder each resistor
as close to the individual tube's anodes as possible.
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Martin B

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Beiträge: 2

Registriert: Mi 22. Mär 2017, 19:49

Beitrag Mi 22. Mär 2017, 20:47

Re: Connect SBT10A tube / Anschluss Zählrohr

I too fuss over the circuitry surrounding my SBT-10

My SBT-10 is working fine at 380v with 22M ballast on every anode and picking up the signal across a 22k on the cathode.
The pulse is about 4V peak with my cheap scope leads.

While recording the pulses (which do not all have the same rise time) I sometimes see a pulse much bigger than usual.

Could this be a muon that triggers 2 segments of the SBT-10 instantaneously?

It would be fantastic if my project had a coincidence function.
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jsbid

Moderator
Moderator

Beiträge: 234

Registriert: Fr 26. Jul 2013, 07:42

Beitrag Do 23. Mär 2017, 08:27

Re: Connect SBT10A tube / Anschluss Zählrohr

Martin B hat geschrieben:My SBT-10 is working fine at 380v with 22M ballast on every anode and picking up the signal across a 22k on the cathode.
The pulse is about 4V peak with my cheap scope leads.

My crystal ball just fell down so the first step would be to point us to
some schematics including notes where you measure what ;-)
<<

Martin B

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Beiträge: 2

Registriert: Mi 22. Mär 2017, 19:49

Beitrag Do 23. Mär 2017, 14:08

Re: Connect SBT10A tube / Anschluss Zählrohr

jsbid hat geschrieben:
Martin B hat geschrieben:My SBT-10 is working fine at 380v with 22M ballast on every anode and picking up the signal across a 22k on the cathode.
The pulse is about 4V peak with my cheap scope leads.

My crystal ball just fell down so the first step would be to point us to
some schematics including notes where you measure what ;-)


I thought I was on topic, have you forgotten the OP?

Just like http://shaddack.brutowave.com/projects/hw_PancakeGeiger/schema.jpg but with 22M on each anode and 22k on the Cathode (which is where the signal is taken from).

The question is - can this tube detect simultaneous events on 2 or more segments?

If so, maybe it would explain the occasional large Cathode pulses I've seen?
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jsbid

Moderator
Moderator

Beiträge: 234

Registriert: Fr 26. Jul 2013, 07:42

Beitrag Do 23. Mär 2017, 14:18

Re: Connect SBT10A tube / Anschluss Zählrohr

Martin B hat geschrieben:I thought I was on topic, have you forgotten the OP?

Nobody says this is OT but as your were NOT the OP, the question of what
you are exactly doing seems legitimate.

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