Please read the attachment.
Luuk
SiPm test
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brehwens
- Posts: 89
- Joined: 27 Apr 2015, 03:49
Re: SiPm test
Hi Luuk!
Wow, this was indeed interesting reading!
These small diodes seem quite easy to hook up, wich I like as I am not very good with electronics.
A question: The small crystal you used, was it "waste" from Scionix or is it possible to buy this crystal size? You coupled it optically to the SiPm; is the surface of the diode tough enough to allow coupling and re-coupling to the crystal?
You write that you filter the incoming power; can you specify a bit more what needs to be done ?
If I understand you correctly, the SiPm works best at lower count rates? What is a good level to be at? (I am thinking, since our sound card based methods work nicely up until 1500 cps or so)
Also, as I understand it the SiPm was not the source of the quite bad resolution using the first crystal, but it was the small crystal itself? Is this inherent to such small crystals, or was it just something with this particular crystal?
Very interesting experiment in any case!
Wow, this was indeed interesting reading!
These small diodes seem quite easy to hook up, wich I like as I am not very good with electronics.
A question: The small crystal you used, was it "waste" from Scionix or is it possible to buy this crystal size? You coupled it optically to the SiPm; is the surface of the diode tough enough to allow coupling and re-coupling to the crystal?
You write that you filter the incoming power; can you specify a bit more what needs to be done ?
If I understand you correctly, the SiPm works best at lower count rates? What is a good level to be at? (I am thinking, since our sound card based methods work nicely up until 1500 cps or so)
Also, as I understand it the SiPm was not the source of the quite bad resolution using the first crystal, but it was the small crystal itself? Is this inherent to such small crystals, or was it just something with this particular crystal?
Very interesting experiment in any case!
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luuk
- Posts: 313
- Joined: 01 May 2015, 21:00
Re: SiPm test
Hi Karl,
There is no CsI(Tl) crystal waist all can be reused, but it is always possible to get one for a low price special if it is just small.
It is simple to couple a crystal to the SiPm I just used coupling compound but it can be glued as well, he surface of the SiPm is protected with a layer so it can be reused for experiments with different crystals.
The CRC filter in the power supply is nothing special just a C from 100nF to ground a resistor from 10KΩ in series with the power line and a gain a C from 100nF to ground.
It will filter some of the ripple and noise from the supply, you don’t want that on the SiPm it will give low energy noise.
The counter rate fully depends on the amount of pixels in the SiPm the more pixels the higher the counter rate can be. I don’t have a correlation between amount of pixels vs counter rate.
Just experimenting is the best and as soon as the spectrum start to get none linear the counter rate is to high!
A crystal that is longer then wide will never have a such a great resolution compared to a e.g. 10mm cube or a round 1x1” crystal.
And the treatment of such a small crystal is more difficult than a large crystal becuase of the size.
Regards,
Luuk
There is no CsI(Tl) crystal waist all can be reused, but it is always possible to get one for a low price special if it is just small.
It is simple to couple a crystal to the SiPm I just used coupling compound but it can be glued as well, he surface of the SiPm is protected with a layer so it can be reused for experiments with different crystals.
The CRC filter in the power supply is nothing special just a C from 100nF to ground a resistor from 10KΩ in series with the power line and a gain a C from 100nF to ground.
It will filter some of the ripple and noise from the supply, you don’t want that on the SiPm it will give low energy noise.
The counter rate fully depends on the amount of pixels in the SiPm the more pixels the higher the counter rate can be. I don’t have a correlation between amount of pixels vs counter rate.
Just experimenting is the best and as soon as the spectrum start to get none linear the counter rate is to high!
A crystal that is longer then wide will never have a such a great resolution compared to a e.g. 10mm cube or a round 1x1” crystal.
And the treatment of such a small crystal is more difficult than a large crystal becuase of the size.
Regards,
Luuk
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brehwens
- Posts: 89
- Joined: 27 Apr 2015, 03:49
Re: SiPm test
Luuk,
I am curious about your last statement, that crystals not being of equal width and height would have a poorer resolution.
The first probe I built was based on a soviet 3x7 cm crystal. The resolution was excllent, well below 7%. Steven has sold his "Red Baron" lines of detectors which are based on the same crystal, also with excellent resolution.
I wonder, apart from the chemical composition (and how well the crystal was manufactured) what will determine the resolution of the crystal? Do you have some Scionix wisdom to share here?
I am curious about your last statement, that crystals not being of equal width and height would have a poorer resolution.
The first probe I built was based on a soviet 3x7 cm crystal. The resolution was excllent, well below 7%. Steven has sold his "Red Baron" lines of detectors which are based on the same crystal, also with excellent resolution.
I wonder, apart from the chemical composition (and how well the crystal was manufactured) what will determine the resolution of the crystal? Do you have some Scionix wisdom to share here?
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luuk
- Posts: 313
- Joined: 01 May 2015, 21:00
Re: SiPm test
Hi Karl,
Sure you can get a good resolution out of a crystal like that, but you will never get the same or better than with a crystal that is more symmetrical e.g. 1x1 or 2x2 etc.
The light has to travel over a longer path in your case 7cm so it start to loose some light and the light also starts to bounce around all these effects will ruin the resolution a little.
The crystal has to be compensated (treated in a special way) to get a good resolution.
That all depends on the ratio, the bigger the ratio e.g. 1x6 the more difficult to get a good resolution.
The way to compensate is the trick I can not tell you how it is done that is company confidentiality, sorry!
Luuk
Sure you can get a good resolution out of a crystal like that, but you will never get the same or better than with a crystal that is more symmetrical e.g. 1x1 or 2x2 etc.
The light has to travel over a longer path in your case 7cm so it start to loose some light and the light also starts to bounce around all these effects will ruin the resolution a little.
The crystal has to be compensated (treated in a special way) to get a good resolution.
That all depends on the ratio, the bigger the ratio e.g. 1x6 the more difficult to get a good resolution.
The way to compensate is the trick I can not tell you how it is done that is company confidentiality, sorry!
Luuk
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brehwens
- Posts: 89
- Joined: 27 Apr 2015, 03:49
Re: SiPm test
Hi Luuk!
No worries on the confidentiality issue, it just got me thinking if the shape is all there is to it, or if a crystal with an "asymmetrical shape" (like my 3x7 cm) has to have a chemically different composition/be made in a special way to compensate for its odd shape.
In any case, the Soviets were successful with the 3x7 cm crystals I and Steven used, so they must have done something right....
Or maybe you are saying that Scionix uses old cold war techniquest when preparing crystals?? :)
/Karl
No worries on the confidentiality issue, it just got me thinking if the shape is all there is to it, or if a crystal with an "asymmetrical shape" (like my 3x7 cm) has to have a chemically different composition/be made in a special way to compensate for its odd shape.
In any case, the Soviets were successful with the 3x7 cm crystals I and Steven used, so they must have done something right....
Or maybe you are saying that Scionix uses old cold war techniquest when preparing crystals?? :)
/Karl
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luuk
- Posts: 313
- Joined: 01 May 2015, 21:00
Re: SiPm test
Hi Karl,
I can assure you that Scionix can still make the best possible detectors in any shape, e.g. we make 1"x8" res. <7%, 3"x5"x16" again res. around 7%., 4"x4" around 6.3% etc.
We are specialized in none standard detectors and make any possible shape I shall show you some pictures(soon) of what we make and what is possible you will be surprised :-)
The point with the small detector is that it is almost impossible to treat it right, have you ever tried to polished or sand such a small detector with cloves on? it is hard to do a 1"is much easier.
regards,
Luuk
I can assure you that Scionix can still make the best possible detectors in any shape, e.g. we make 1"x8" res. <7%, 3"x5"x16" again res. around 7%., 4"x4" around 6.3% etc.
We are specialized in none standard detectors and make any possible shape I shall show you some pictures(soon) of what we make and what is possible you will be surprised :-)
The point with the small detector is that it is almost impossible to treat it right, have you ever tried to polished or sand such a small detector with cloves on? it is hard to do a 1"is much easier.
regards,
Luuk
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brehwens
- Posts: 89
- Joined: 27 Apr 2015, 03:49
Re: SiPm test
Hi Luuk!
I don't doubt Scionix makes excellent detectors, but for us "non-professionals" it can be a bit of a mystery what exactly makes a crystal good or bad, and that is the reason for my questions.
For example, (and just a general question), do you use a different chemical composition (or growth method) if you want to make small crystals compared to big crystals (or odd shapes vs "normal" shapes). Of course you don't need to (or can) go into details, but it would be interesting to know if all crystals essentially contain the same NaI(Tl) mix, or if this also is varied on purpose.
Look forward to the pictures! I guess we will see som items hardly found on ebay.... :)
I don't doubt Scionix makes excellent detectors, but for us "non-professionals" it can be a bit of a mystery what exactly makes a crystal good or bad, and that is the reason for my questions.
For example, (and just a general question), do you use a different chemical composition (or growth method) if you want to make small crystals compared to big crystals (or odd shapes vs "normal" shapes). Of course you don't need to (or can) go into details, but it would be interesting to know if all crystals essentially contain the same NaI(Tl) mix, or if this also is varied on purpose.
Look forward to the pictures! I guess we will see som items hardly found on ebay.... :)
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luuk
- Posts: 313
- Joined: 01 May 2015, 21:00
Re: SiPm test
Hi karl,
All crystals e.g. NaI(Tl) but other as well are made of the same material no matter is a detetctor is big of small or special shaped.
Luuk
All crystals e.g. NaI(Tl) but other as well are made of the same material no matter is a detetctor is big of small or special shaped.
Luuk
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pietkuip
- Posts: 56
- Joined: 29 Apr 2015, 06:23
Re: SiPm test
SiPM with a small crystal would cute as an add-on for a smartphone.
What would be the most suitable electronics to get an audio-frequency pulse?
What would be the most suitable electronics to get an audio-frequency pulse?
