Wanted: PIN Photodiode

Hello Shyam:

I note the sensitivity of the examples you give are around 960 nm. You request 500nm.

However I have pasted a page of searches below. Search term: photodiode 10x10mm. Search page:

http://www.google.co.uk/search?hl=en&rlz=1T4GGLJ_enGB294GB294&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=photodiode+10x10mm&spell=1If they ate not what you want can you get back to me and say what these diodes will be used for please?

1. Laser power meter, laser energy meter, laser beam profiler, laser ... Ophir Laser Measurement Instruments Photodiode Heads BC20, BC20, Meter for scanned beams at up to 30000 inch/s, 10x10mm, 633, 650, 675nm, 50µW-20mW ...
   www.ophiropt.com/laser-measurement-instruments/laser-power-energy-meters/products/smart-sensors/photodiode-sensors - 51k - Cached - Similar pages
2. Development of neutron detector using the PIN photodiode with ... A Si photodiode detector, PIN type, 10x10mm, with a. slim film of a converter material, capable to produce charged. particles, was used as sensor of ...
   ieeexplore.ieee.org/iel5/8777/27793/01239344.pdf - Similar pages
   by CH Mesquita - Related articles - All 4 versions
3. Catalogues - laser-power-meters - ophir-optronics Photodiode Heads for Low Power 10pW-3W. Head. Features. Aperture. Spectral Range . Power Range. Page. PD300. Automatic background subtraction. 10x10mm ...
   pdf.directindustry.com/pdf/ophir-optronics/laser-power-meters/12595-19708-_2.html - 68k - Cached - Similar pages
4. S5870 Si PIN photodiode,Si photodiode array, Hamamatsu Product Details and Specifications for the S5870Si photodiode array. ... Dual element Si PIN photodiode, 10x10mm, chip carrier type, for laser beam ...
   sales.hamamatsu.com/en/products/solid-state-division/si-photodiode-series/si-photodiode-array/part-s5870.php - 23k - Cached - Similar pages

I hope these do help but tell me if they do not.

Take care and happy holiday!.............

Dear babybear

Thanks for lots of information.

For scintillator detectors using photodiode there is always some problem with speed and sensitivity in mid visible range. Rise time of the order of <30ns may be acceptable but not very slow as scintillation peak is usually very fast.

Perhaps PM Tubes are better choice but will like to try low cost PIN and APD detectors also if I can find fast enough and having good enhanced sensitivity in UV and visible. I do not have phosphor for IR range.

Hello Shyam,

It would have been a lot easier to find stuff when searching if you had written that in your OP.

So ideal you are looking for 30ns? Why does it have to be so fast. Is it a safety feature which stops something working if it 'even thinks' of flashing?

I will check out PM tubes as well. I want to see what they are for and then try and judge which is more suitable?

Take car and happy holiday!

PM Tubes are usually very fast and have rise time of 1ns to 10ns range. Some photodiodes are also fast and I am looking for these. Perhaps 10mm x10mm photodiode will be fast enough but larger area version likely to be slow.

Scintillator signal peak is about 30ns from start and lasts about 200ns for NaI:Tl scintillators. Some scintillators like BaF2 are as fast as 500ps in their rise time of fast component.

I have some photodiodes that have 100ns rise time so not so good for very fast signals I am looking at.

APD of 10mm x10mm will also be great if I can get these of fast response and visible sensing.

Hello Shyam,

Well you are doing your bit in 'sensible' R&D! I will keep in touch OK?

Yes, I am designing a radiation detector for environmental monitoring. See the output of the existing 10mmx10mm PIN detector with 10mmx10mmx5mm CsI:Tl scintillator. The rise time in this detector became 1us due to poor response of the photodiode else the risetime should have been about 30ns and peak height much larger than seen here.

I have another noise filtered picture here. This one taken by signal averaging. Sharpness of the edges is also bad here otherwise pulse shape is identical. I need much faster PIN photodiodes or APD. Right now detector can handle at best 10000 pulses per second and I need to reach near one million/s using faster detector.

Hello Shyam,

I thank you for the pics! Makes it a lot clearer as to what you want to 'make'.

Had some problems and took 5 hours to get my computer going, and you are one of the first I have replied to. I will look, but it may be after the holidays now before I can find anything. I will check later though.

Can you tell me what the APD means? I am not familiar with it. Is it 'Auto Photo Diode'?

APD are avalanche photodiode or photo detectors. These have gain of 200 to 10 million range and hence work as light sensor plus fast amplifier in one package. Usually these are in the range of $200 but now Intel has developed cheaper silicon based APD that may be just $10 each. APD are prone to damage as they have spark like electron multiplication due to high voltage field inside the solid semiconductor. Electrons travel at high speed, gain velocity and then transfer energy to many more electrons to become free to create high charge in a short pulse. Perhaps APD are more like channel electron multiplier or Micro Channel Plate Detectors (MCP).

Hello Shyam,

I appreciate the explanation. The first site I went to explained all I needed to know, so, that is clear in my head . I thank you replying so quickly though, OK?

I am tired now. see you later.

Hello Shyam,

I forgot to ask exactly what kind of radiation are you checking for? What wave length?

While photodiode senses 540nm, the sensor as such with scintillator senses x-rays and gamma rays of high energy.

Radiation detector here senses Cosmic Gamma Rays. For testing purpose, CS-137 660keV Gamma energy photons were also used.

No these detector assemblies are ready for education and training for engineers and I will like to send these to Science and Engineering Institutes in India for training purpose. We have about 10000 such Institutes in India. I think I can also send these abroad if there is any request coming from other nations for education purpose.

Hello Shyam,

I leave it in case it is any use.

Can you tell me if the 'rise time' or the 'decay' time is the more important?

This page has the properties of different substances and doped PINs etc.

http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/23/4545061/04545191.pdf?arnumber=4545191

This is an extract and deals with the doping with rare earth Ions.

Take care, I am going to bed as I was woken after only 1 hour and am just too tired.

See you soon and good luck. Let me know when you close for the holidays please?

Take care and have a wonderful holiday!...........................

Many scintillators have a very fast light output component at room temperature in the range of 500ps to <30ns and also have slow component 200ns to 20us. I am looking at the fast components from larger surface area of the crystal phase of 10mmx10mm to 50mmx50mm and hence larger fast PIN photodiode or APD is the thing of my interest.

I have slightly improved my amplifier today by adding another amplifier to it. It also increased the gain and output goes to several voltage now. Rise time is still slow to about 500ns as the photo-diode I used here is same type.

I have added pulse shaping to above signal and now peak looks somewhat round shape and such signals are much better for peak height measurement.

Hello Shyam,

Appreciate your replies, thank you.

With the more rounded top after the rise, it now seems to be a couple of 'degrees lower. Is that reckoned to be a more accurate measure than the peak shaped one?

So you are looking for photo diodes between 10mm and 50mm, is that right?

I am still looking. Can put a little more effort into in now as I am awake! Yesterday I was half asleep.

Take care and happy holiday...............

yes, the round shape at top gives more time to look at the stable peak potion. Sharp peak otherwise can get missed before it is sensed by slow peak detector circuit. These signals were recorded at 2GSPS sampling speed using Tektronix TDS2024 DSO. While in actual use, I need to build a low cost small circuit to achieve it.

In these signals initially charge is converted into peak voltage and tail is simply created by slow decay of charge and is not important. Passing the signal to another integrator turns the sharp peak into a round shape signal and also removes noise as it is a low pass filter.

How much fast the peak signal finally become, depends on the light pulse rise time, photodiode rise time and amplifier rise time. While the light pulse for my experiment is very fast, photodiode are rather slow. Amplifier is very fast. The intermediate poor photodiode makes things bad.

Hello Shyam,

Thanks for the reply post.

I do understand what you mean. It is a shame you cannot connect the PIN direct to the amp, instead of going through a bus. If you could you could try it and 'work backwards' towards stabilising the signal once you found you can measure the signal virtually direct? Though I really do realise it may be a little more complicated than that!!!

I am still looking and now I know what you are trying to do in detail I can search for the right terms!

Take care my friend. I am surprised no one else has joined your thread to help?

Hello Shyam,

I am typing from memory (which is not good!).................

You say you have some scintillators with R time 50 ns. And you are looking at 1ns or better >ps.

What is the fastest response time you have measured so far? And was that with easily available scintillators. And does this include Barium Fluoride? Can you handle BaF2 substrate or not. Do you want a faster crystal? Say, into X-ray?

http://www.ias.ac.in/jarch/pramana/52/49-65.pdf

I do not know about price. But can you view this site which has a paper on the development of a low cost single and multi-channel Vacuum photo-diode which has been used to study X-rays in LLP. Or is this totally the wrong kind of use?

I thought I would check out faster 3/4/5/600 ps/crystals. Can you let me know what you think please?

Yes, you are right. The vacuum diode used by this team at center for advanced technology is real fast. However it needs vacuum and hence useful only on lab type large and expensive setup. Channel electron multipliers are also used but they work in vacuum. My application is for open air experiments and at the lowest possible cost <$200.

Hello Shyam,

Thank you for your reply.

I will look for non vacuum items then!

Thank you again.....................

Hello Shyam,

These may be too small but they are fast.

http://www.osioptoelectronics.com/product_detail.asp?id=14&series=Silicon+Avalanche+Photodiodes+%28APD%29

Yes, they are good APD. but they are of smaller size than what I need.

Hello Shyam,

Can you use several to form a composite? Or perhaps to can tell me what you are looking for now? This interests me a great deal.

Take care and good luck in your endeavours!

yea, I can use many if they are in square shape such that they fit in without leaving to much gap in between.

Hello Shyam,

how are you?.............I have had a few problems so have not been able to search.

If you can, and you are still looking for pin photo diodes, can you bring me up to date? Or it is just 'take note' of your last two or three posts?

Take care my friend..................