Detector type

Scintillation crystals, PMTs, voltage dividers etc...
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keuleeule
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Detector type

Post by keuleeule » 15 Nov 2016, 09:24

Hi all,
in Stevens video https://www.youtube.com/watch?v=Mp0QYHiS7lU
the right one of the blue scintillator on the table looks like my Harshaw 12S8 introduced here: viewtopic.php?f=2&t=222
does anyone have data to that detector? Which PMT is used, I cant find anything in the www about it...
and as it seems sealed in aluminum I cannot have a look inside.
I would be able to x-ray it at work, but does it make any sence?

thanks for any hint, Kolja

luuk
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Re: Detector type

Post by luuk » 16 Nov 2016, 04:27

Hello Kolja,

You have to remember that your detector is at least 23 yearsold because we(Harshaw) stopped in 1993 with the production of detectors d but I expect looking art the identification label it is >35 years old.
The pmt that were used in those days could be a Emi 9758B that was used a lot in that time, but it could also be a any 3” Burle or Philips tube.
It is a integral line detector, so the pmt is direct coupled to the crystal the can is 0.5mm thick aluminium an it has an internal mu-shield there is further not much to tell about.
There is not much to see if you make and x-ray from it.

Luuk

keuleeule
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Re: Detector type

Post by keuleeule » 16 Nov 2016, 09:11

Hi Luuk,
much more then I found so far, so thank you very much !
I just want to make sure that I dont mess up my circuit which I will prepare the next weekend.
The divider circuit I mean - as I found several different 14pin layouts in www specially EMI with that schematics like attached.

BTW: I found during unsoldering my Hershaw a PCB with a date on it "SEV 13.5. 1975" wow. Hope the crystal is still ok.
SEV for secondary electron multiplier...

Good, I will find out.
Thanks a lot, Kolja

edit:
entering your mentioned Emi 9758B I will find this schematic - so that will fit with the common circuit
Attachments
PMT_Emi 9758B.png
PMT_Emi 9758B.png (102.19 KiB) Viewed 1921 times
PMT_EMI.png
PMT_EMI.png (196.01 KiB) Viewed 1921 times

luuk
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Re: Detector type

Post by luuk » 17 Nov 2016, 07:03

Hello Kolja,

Can you show me a picture of the pmt base now that you removed the vd/amplifier? Is it a 14 pins slotted base or do you have just wires coming out of the pmt?

Luuk

keuleeule
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Re: Detector type

Post by keuleeule » 17 Nov 2016, 17:37

Hi Luuk,
Both my detectors have a blue 14 pin socket, no wires. Both capsuled in aluminum.
I can take a picture later on.

Still having problems to get 3kv 10nF keramic capacitors , our large "consumable" electronic store in germany do not have them, And their metal film caps are huge. I will build up the divider this weekend, the auspost parcel is still down under, so no hurry.

Thanks, kolja

keuleeule
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Re: Detector type

Post by keuleeule » 17 Nov 2016, 17:43

In an other post from you I learned now that an integral line detector cannot be seperated in case crystal or pmt is dead, so i hope they are ok. Otherwise i found a good seller already ;)
Kolja

keuleeule
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Re: Detector type

Post by keuleeule » 17 Nov 2016, 21:32

Today I got the ceramic capacitors, perfect, I know what to do on Weekend.
Kolja

luuk
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Re: Detector type

Post by luuk » 18 Nov 2016, 08:13

Hi Kolja,

The 14 pin blue base can have a different connection than in the data sheet you found from the pmt, because we mounted them our self and connected them according to the customers request.
Most times the connections are as follows(positive high voltage only)
14= Cathode
13= Focus or if no fucus than n.c.
12 =n.c.
11 = Anode
10 to 1 = dynodes 10 to 1 but if there are only 9 dynodes then pin 1=n.c.

If you make your own voltage divider you most capacitors don’t have to be high voltage, the 10nF over the last 2 or 3 dynodes can be 400V or max. 1kV because the voltage between the dynodes is most times not higher than ±250 V.
Only the serial signal capacitor needs to be around 2kV unless you want to work with an high voltage >2kv and that is not advisable!

Luuk

keuleeule
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Re: Detector type

Post by keuleeule » 18 Nov 2016, 10:21

Hi Luuk,
as promised a picture of both PMT.
You are right, as both have "S/N" on the 14pin socket, that both are Harshaw...

Thanks for the information!
regards, Kolja
Attachments
20161117_233936_kl.jpg
20161117_233936_kl.jpg (211.14 KiB) Viewed 1886 times

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