LYSO crystal scintillators

Hi! Some time ago I’ve bought some 4x4x22mm LYSO Crystals to make a scintillation probe or just to test they.

From the manufacture:

LYSO crystal is an ideal generation scintillator crystal. LYSO (Cerium-doped Lutetium Yttrium Orthosilicate). LYSO crystal has the advantages of high light output and density, quick decay time, excellent energy resolution and low cost. These properties make LYSO an ideal candidate for a range of ray detection applications in nuclear physics and nuclear medicine, which require higher, improved timing resolution and superior energy resolution. “

The seller on ebay is the well know: “The Rad Lab”. For 12$ I’ve received 2 crystals. They are for sure intended to use into a proton emission tomography machine “PET”. More docs from Saint Gobain:

LYSO datasheet  NextGen LYSO


The Rad Lab LYSO Crystals

Some more info about this type of crystal:


Crystals in their package

I think this crystals are from a PET machine who was scrapped… but hey, they works great! Take a look at how they react when are exposed to some UV light.

LYSO crystals under UV light

This type of scintillator crystal is a bit radioactive because of Lu176 inside it. That’s makes it a nice calibration source for my spectrometer,

I’ve made this gamma ray spectrum of my LYSO crystals. To make it I’ve used PMT R6095 + 30x30mm NaI(Ti) scintillator at 8% FWHM. Peaks of Lu176 at 201.8keV and 306.8keV

LYSO: this is a recording in a XML file of this spectrum. To be used with BecqMoni2011 software.

LYSO gamma ray spectrum

MadExp PMT adapter

You can download the Madexp PMT adapter Kickstarter version manual here: manual
UPDATE 18 Feb. 2018 I’ve analyzed my home radioactive background simply leaving the MadExp PMT connected and running for 100 minutes on the table top. The result is this:

UPDATE 10 Feb. 2018
I've completed my first example of MadExp PMT adapter and it's NaI(Ti) probe. 
I'm making some test with it. Three audio samples was recorded with it and are listed below.
This one is my location gamma backround
This is an Am241 alpha emitter capsule from smoke detector
This is the sound of an highly active (15mSievert/h) Pechblende uranium ore

In this video you can see my first PMT test.

How to power and aquire signal of a scintillation probe?

You I need some high voltage and signal conditioning circuit! Inspired by the Theremino PMT project, I’ve decided to build my own customized version of their circuit.

My project goal is to make an all-in-one photomultiplier tube power supply and audio ADC powered by a single USB cable. The high voltage generator is regulable in the range 700-1500V with a simple trimmer.

Corrent status of the project:

  • Schematic at version 2 (erros corrected)
  • PCB routing ready
  • First batch of PCB’s arrived from chinese manufacturer
  • First complete prototype ready and working
Schematic V2.0

To enlarge the schematic right click on the image and select “Show Image” or download it and zoom with your image viewer.

In order to make the CM108AH working you absolutely need to add the 47 ohm series resistors on USB D+ and D- data lines with a pull-up resistor of 1.5K from the ic’s 3,3V out to D+. I’ve lost a lot of time to understand this simple thing… but not so obvious!

This is the PCB board top layer

With my CNC engraver I’ve made some engravings to the PMT adapter enclousure… as a first test I’ve messed with the cutting deep/speed.

The video below is my first test of the circuit

First test connecting the adapter to my pc soundcard. The program is Theremino MCA, is not calibrated… I need to set each control of the MCA at the right position so I need some time for setting up it.

Testing a camera lens containing thorium
Testing a natural Pichblende sample from a mine situated in northen Italy.

NE5534 RIAA amplifier

Some time ago I’ve received a Technics SL-1910 turntable from a friend. At that time mine problem was that this turntable doesn’t have integrated RIAA network and my vacuum tube stereo doesn’t have too. I needed an external RIAA active network to equalize the audio from the turntable and rise it’s volume to the 1,5Vpp needed to drive the stereo amplifier. I’ve designed a simple active RIAA network powered by a low noise op-amp NE5534 or OP27 or other pin-to-pin compatible op-amp’s. I’ve made some PCB’s for it too. I sell the PCB at 5€/each plus shipping. Contact me for more info or buy.

The PCB populated
RIAA schematic.

The simulated circuit result and the result from the real circuit measure fits very well.

Frequency response simulation
Real frequency response, please note that actually the dB loss is a dB gain. +35dB at 20Hz and 0dB at 20Khz aprox.

All resistors are 1/4W

  • All capacitors must be high-quality poliestere but I’ve used standard ceramic type without any issue
  • IC’s are mounted on DIP-8 package
  • I/O are made soldering directly coax cable from RCA sockets to the pcb
  • The circuit is powered by 2x 9V battery to minimize noise from power supply. I use a connection like this to power the circuit. Just add a double trow switch to connect/disconnect the +9V and -9V supplies.
Battery connection diagram
  • The output cap must be a 2.2uF polyestere non polarized from WIMA or high-quality equivalent.
  • The PCB that I’ve realized is 100x50mm in size, 1.6mm FR4 thick, double layer professionaly made. There are 4 mounting hole at corners. The PCB is noise free without any enclosure thanks to my  design but I sugest you to enclose it into an alluminium enclosure like this one, cheap, from
  • For I/O use only quality gold plated RCA connectors mounted on the alluminium front/real panels


Riaa_1 click here to read the BOM (bill of materials)

NaI(Tl) Crystal scintillator

This type of scintillator material is the best one that an hobbist could afford. At the moment NaI(Tl) crystals are easy to find on eBay from russian or ukrainian sellers. Take care that NaI(Tl) are highly higroscopic and if they absorb too much water they turn color to yellow than brown and finaly their light output drop to unusable level. As the majority of the scintillation materials, they are used coupled with a photomultiplier tube for Gamma Spectroscopy.

Gamma Spectroscopy probe

Some pics of my gamma-spectrometer crystal + PMT probe.

A 25mm diameter NaI(Tl) crystal mounted on my gamma-spectrometer probe.
NaI(Tl) + PMT inside an alluminium enlosure + Madexp USB PMT adapter measuring a radioactive source
A 10mm NaI(Tl) crystal with it’s alluminium enclosure, packaging and datasheet
NaI(Tl) crystal optical window

BC408 BC412 Plastic scintillators from Bicron

Some weeks ago I’ve bought from an US eBayer some cilindrical shaped plastic scintillators. From wikipedia “A scintillator is a material that exhibits scintillation — the property of luminescence,[1] when excited by ionizing radiation. Luminescent materials, when struck by an incoming particle, absorb its energy and scintillate”. This means that you can make a very  sensible radiation counter using a scintillation material coupled with a PMT to detect his ligh pulses.

Scintillation probe
Gamma Spectroscopy / scintillation probe

One is 1” diameter made of BC408, the other is 1-1/2″ of BC412.


This type of scintillators are very easy to use and cople to a photomultiplier tube, they just need some silicone coupling gel and a proper light tight enclosure to work. I’ve bought some otical coupling silicone too.

Optical coupling silicone

A simple way to determine that this pieces of plastic will work is to test with some UV light. If they are sensible to radiations they are sensible to UV too.

Some tech info about this type of plastic scintillators.


Here you can download the complete datasheet: sgc-bc400-404-408-412-416-data-sheet

SV500 Geiger counter from German Army

Hi everyone, today I’m writing about my new SV500 Geiger counter from German Army. Mine was bought from a german eBay seller specialized in surplus measuring equipment. I’ve bought it for 145€ plus shipping. Nice price!

eBay auction of the SV500

The SV500 that I’ve received have included the internal gamma probe, the external gamma + beta probe, a probe clamp, probe cable, battery extension cable and earpiece.


I’ve read a lot of reviews around internet about this counter. Most if not all of they tell that this counter is very insensitive.

This is absolutely BULLSHIT! If peole doesn’t have true radioactive sources like a piece of Pechblende or a sample of Radium… why they bought such a counter? This one is intended to be used on a nuclear war combat field. The smallest scale of the instrument could tell you if what you are prone to eat is radioactive or not and, carried around with you, it will beep with it’s selectable alarm if you are aproaching a dangerouse contamined zone.

It’s an instrument made to keep you alive not to measure micro Sieverts from Radon in your room or thorium in your camera’s lens.

SV500 in action measuring Pechblende

In this pic you can see that my Pechblende reach 15 milliRad/h of beta+gamma on direct contact with the probe.

Cables and connectors
Left side pocket: battery and internal gamma probe
View of the counter, closed

I could ounly recomend this counter, if you find one at a good price in good condition, buy it! Mine have a calibration mark on the back, it was calibrated in year 2008 so 9 years ago… at the moment it is my best calibrated instrument he he he.

I’ve made a video of it in action:

Some other images of the counter:

Front pannel
Backlight in operation
External gamma probe
External gamma probe with beta window opened
Front pannel and connectors
Battery holder