Hardware Hacking

This project is just for fun, where I'm using 20 Geiger–Müller Tubes (GMT) arranged in a half-hexagon like array.  Coincidence between two or more tubes will be process by an array of AND Gates where the TTL output will be converted to an audiovisual display using Arduino Mega 2560 to show the direction and frequency of cosmic rays (muons) passing through the detector.

Unfortunately due to limitations in the speed of I/O polling in the Arduino Mega 2560 the coincidence between tubes wasn't possible on a software level and so I'm currently in the process of constructing a protoype.

  Working prototype June 2011 with 20 X TTL 5V+ pulses when an ionizing particle is detected within each GM tube.

 

A very rough animation of how the tubes maybe triggered as a Cosmic Ray Muon flies through the detector array.

20 wired GMTs installed between two plastic brackets

 

Schematic of how each GMT limb will be connect to the I/O Card

1 of 4 PCBs - This board supports 5 limbs of the schematic above.

The I/O Card - Arduino Mega 2560

Schematic of 400V and 5 V power supply

Drilled completed bracket for holding GMTs

Drawing dimensions of the bracket for holding GMTs

Geiger-Müller Tube (GMT) CI-1
I'm also using Russian Geiger-Müller tubes in this experiment which are described as being Gamma sensitive and available on ebay at very low cost less than the common SBM-20 Tubes that I have use before.

Specifications
Gamma Sensitive: unknown rate
Working Voltage: 360 - 440V
Plateau: Length/ Inclination: 80V/0,125%/V
Own Background: 0,4 Pulses/s
Load Resistance: 5 - 10 MOhms
Working Temperature Range: -400 +500 С
Length: 90mm
Diameter: 12mm