Mechanical details
The Null Gamma Device is based around a 1.4 GHz 64-bit quad-core Raspberry Pi 3 Model B+ single board computer. The entropy source at it’s heart (the Null source) is the cumulation of various quantum and electrical effects on photo sensors within a blacked out 8 Mbit camera operating at ISO 800. The higher the ISO setting, the higher the entropy rate. The device’s Linux (Raspian) operating system is hosted on an SSD drive for reliability and longevity.
Entropy generation is essentially the same process as within the Photonic Instrument, other than there being no photon noise as the camera operates in complete darkness.
Basic hardware components (stock photo).
SSD drive hosting the Raspian/Linux operating system (stock photo).
The image below is an initial test assembly of the principal components. You can see the Null source on the right hand side, next to the photon shield (black protective enclosure and secondary light barrier). The SSD drive is beneath the Pi, connected via a SATA to USB adapter cable.
Test assembly of the Null Gamma Device.
The CMOS camera is the Null source. The camera is obscured simply by super-glueing a 1.6 mm opaque plastic square directly onto the lens mount. It is beneath the focusing crystal. The camera has been successfully tested for light tightness. Zero light ✔
There is also a DS18B20 digital thermometer adjacent to the camera for temperature monitoring. It is bypassed with two 100 nF ceramic capacitors for good luck. This allows us to assess the relationship between the Null source’s entropy rate and it’s operating temperature.
