Transcript Project RNG: Radiation-Based Random Number Generator

Senior Design
Project RNG: Radiation-Based
Random Number Generator
• Team Oregon Chub
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Colton Hamm (Team Leader)
Alex Brotherston
Advisor:
Ashley Donahoo
Dr. Hoffbeck, Dr. VanDeGrift,
Matt Johnson
Dr. Osterberg
Industry Representative:
Mr. John Haner
Bonneville Power Administration
University of Portland
School of Engineering
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Senior Design
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
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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
3
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Additional Accomplishments
• Interfaced Geiger tube with high-voltage
supply
• Shaped the output of the Geiger tube into a
digital signal
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School of Engineering
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Senior Design
Plans
• Complete final report V0.9 and V0.95
• Interface Geiger tube with CPLD
University of Portland
School of Engineering
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Senior Design
Milestones
Status
Completed
Description
Use .abl file to create
CPLD macro model
Original
Target
Previous
Target
Present
Target
10 Dec 10
10 Dec 10
10 Dec 10
Completed
Analog parts ordered
17 Dec 10
17 Dec 10
17 Dec 10
Completed
Construct and test pulse
generator/transformer
31 Jan 11
31 Jan 11
23 Jan 11
Completed
Verify CPLD functionality
6 Feb 11
6 Feb 11
6 Feb 11
Completed
Verify 7-seg display and
decoder functionality
6 Feb 11
6 Feb 11
2 Feb 11
Completed
Construct and test the
prototype voltage multiplier.
14 Feb 11
14 Feb 11
11 Feb 11
Completed
Construct final voltage
multiplier
21 Feb 11
21 Feb 11
20 Feb 11
Completed
Interface pulse generator,
transformer, voltage multiplier,
and Geiger tube
14 Mar 11
14 Mar 11
22 Feb 11
On Track
Final Report v0.9
13 Mar 11
13 Mar 11
13 Mar 11
On Track
Interface Geiger tube and CPLD
30 Mar 11
30 Mar 11
21 Mar 11
University of Portland
School of Engineering
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Senior Design
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
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Senior Design
Conclusions
• CPLD and display have been tested
• Geiger tube works
• We are now focused on interfacing the
Geiger tube with the CPLD
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School of Engineering
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Senior Design
Questions?
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School of Engineering
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Senior Design
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Senior Design
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
V
University of Portland
School of Engineering
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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.
Senior Design
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.
0v
-40v
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
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School of Engineering
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