Senior Design 1 Project RNG: Radiation-Based Random Number Generator Team Oregon Chub –Colton Hamm (Team Leader) –Alex Brotherston –Ashley Donahoo –Matt Johnson University of Portland School of Engineering Advisor: Dr. Hoffbeck, Dr. VanDeGrift, Dr. Osterberg Industry Representative: Mr. John Haner Bonneville Power Administration

Senior Design 2 Introduction Our project generates random numbers from radioactivity Building a radiation sensor, designing a MOSIS chip and using 7-segment displays University of Portland School of Engineering

Senior Design 3 Scorecard Tested and verified CPLD functionality. Tested and verified 7-segment display and decoder functionality. Met with Allen about case design. University of Portland School of Engineering

Senior Design 4 Additional Accomplishments Interfaced Geiger tube with high-voltage supply Shaped the output of the Geiger tube into a digital signal University of Portland School of Engineering

Senior Design 5 Plans Complete final report V0.9 and V0.95 Interface Geiger tube with CPLD University of Portland School of Engineering

Senior Design 6 University of Portland School of Engineering Milestones StatusDescriptionOriginal Target Previous Target Present Target CompletedUse.abl file to create CPLD macro model 10 Dec 10 CompletedAnalog parts ordered17 Dec 10 CompletedConstruct and test pulse generator/transformer 31 Jan Jan 11 CompletedVerify CPLD functionality6 Feb 11 CompletedVerify 7-seg display and decoder functionality 6 Feb 11 2 Feb 11 CompletedConstruct and test the prototype voltage multiplier. 14 Feb Feb 11 CompletedConstruct final voltage multiplier 21 Feb Feb 11 Completed Interface pulse generator, transformer, voltage multiplier, and Geiger tube 14 Mar Feb 11 On TrackFinal Report v0.913 Mar 11 On TrackInterface Geiger tube and CPLD30 Mar Mar 11

Senior Design 7 Concerns/Issues MOSIS chip will not be ready by founders day. Using a CPLD will have a negative effect on our form factor. Concerns regarding battery power, especially with the large display for founders day. University of Portland School of Engineering

Senior Design 8 Conclusions CPLD and display have been tested Geiger tube works We are now focused on interfacing the Geiger tube with the CPLD University of Portland School of Engineering

Senior Design 9 Questions? University of Portland School of Engineering

Senior Design 10

Senior Design 11 Secret Geiger Tube Slides Model: Geiger Tube as a Switch Switch=open, V=500v Switch Closes, V= 500v*10M/(1M+10M)=455v The capacitor blocks DC, so the signal starts at 0 volts, and falls by 45 volts when the switch closes University of Portland School of Engineering V

Senior Design 12 University of Portland School of Engineering 0v -40v A Geiger–Müller tube consists of a tube filled with a low-pressure inert gas, such as neon, and an organic vapor or a halogen gas. The tube contains electrodes, between which there is a potential difference of several hundred volts, but no current flowing. The walls of the tube are either entirely metal or have their inside surface coated with a conductor to form the cathode while the anode is a wire passing up the center of the tube. When ionizing radiation passes through the tube, some of the gas molecules are ionized, creating positively charged ions, and electrons. The strong electric field created by the tube's electrodes accelerates the ions towards the cathode and the electrons towards the anode. The ion pairs gain sufficient energy to ionize further gas molecules through collisions on the way, creating an avalanche of charged particles. This results in a short, intense pulse of current which passes (or cascades) from the negative electrode to the positive electrode and is measured or counted. -Wikipedia