1. Compact Neutron Generator Technology
OVERHOFF TECHNOLOGY
Compact Neutron Generator Technology
Models: JNG-2-DD/DT
&
JNG-3-DD/DT
---Robert Goldstein
Technical Associates,
North American Distributor

2. A Brief Overview of Neutron Sources
Naturally Occurring/Environmental
Cosmic
The Solar Wind.
High energy charged particles which hit nuclei in the earth’s atmosphere creating secondary particles including neutrons. Intensity varies inversely with solar activity.
Terrestrial
Spontaneous fission mostly U-238, less than 10% naturally induced U-235 fission.
232 Cf

3. A Brief Overview of Neutron Sources
Intentional
Radioisotope sources
Photoneutron Sources
Accelerator sources
Nuclear reactors
Spallation sources
Neutron generators

4. A Brief Overview of Neutron Sources
Intentional
Radioisotope sources
252 Cf SP ½ life 100yr, E(n) 2.3MeV
Table 1.1 Properties of commonly used (ũ,n) sources
Source
Ea (MeV)
T 1/2
Yield (n/a)
210Po+BE
5.30
138.4 days
0.7 x 10-4
226Ra+Be
4.78, 4.59
1.622 x 10 3 years
1.8 x 10-4
239Pu+Be
5.15
2.44 x 10 4 years
0.6 x 10-4
241Am+Be
5.48
4.60 x 10 2 years
242Cm+Be
6.11
163 days
1.1 x 10-4
241Am+B
1.0 x 10-5
241Am+F
4.0 x 10-6

5. A Brief Overview of Neutron Sources
Intentional
Photoneutron Sources
Radioisotope decay with Gamma energy exceeding the neutron binding
energy of a nucleus can eject a Be or D2 neutron, called a photo-neutron
Table 1.2 Properties of commonly used photoneutron sources
Source
E7 (MeV)
T 1/2
Yield (n/β) cm 2 gm -1
24Na+Be
2.757
15.1 h
3.8 x 10-6
24Na+D2O
7.3 x 10-6
72Ga+D2O
2.51
14.3 h
1.9 x 10-6
124Sb+Be
1.691
60.9 days
5.1 x 10-6
140La+Be
40.2 h
0.08 x 10-6

6. A Brief Overview of Neutron Sources
Intentional
Accelerator Sources
The simplest way to use an accelerator to generate neutrons is to use the bremsstrahlung from electron accelerators such as synchrotron or beta tron to produce photoneutrons. This gives a continuous energy distribution which is not very useful.
Pulsed electron linacs can also be used, for example electron bombardment of Uranium can produce 30MeV neutrons.

7. A Brief Overview of Neutron Sources
Intentional
Nuclear reactors and Spallation sources
Are beyond the scope of this presentation.

8. A Brief Overview of Neutron Sources
Intentional
Neutron Generators
A subset of the accelerator category which are also fusion devices. First used in 1933.
These small electrostatic accelerators use one of two exothermic reactions (produces energy):
D + 2H --> 3He3 + n MeV
D + 3H --> 4He3 + n MeV

9. A Brief Overview of Neutron Sources
Intentional
Neutron Generators
A Metal Hydride Target is Utilized
After the Reaction:
The He and n travel in opposite directions producing high neutron yields.
Energy at different angles is given by:
4En = En d +2(2 En Ed )1/2cos Θ = 3Q

10. JNG-2 – Neutron Generator Benefits:
Portability
Reduced Power Input Requirements
Increased Neutron Output
Adaptable for Tailoring to Specific Customer Needs.
Reduced Manufacturing Costs
High Reliability and Long Operating Life

11. Applications: Non-Destructive Testing
Homeland Security / Military
Nuclear Industry
Mining and Drilling
Medicine
Civil, Aeronautical, & Nautical Engineering
Research Laboratories

12. Typical Target Based Neutron Generators versus JNG-2
Typical Neutron Generators
JNG-2
Design
Complicated with Many Electronic and Physical Components
Simple, mechanically based
Power Consumption
Tens of Kilowatts
90 Watts
Neutron Output
10*6 n/s to 10*8 n/s at applied voltages in the range of hundred kV+
DD – 1*105 n/s
DT – 1*107 n/s
Case Diameter
Varies
13 cm
Case Length
65 cm
Weight
33 lbs – 362 lbs
28 lbs
Operation
Deuterium – Deuterium – DD
Deuterium – Tritium - DT
Projected Lifetime
1,200 hours – 4,000 hours
3-5 Years with Option to Refuel and Service at End Time

13. Neutron Generator – Basic Process

14. Homeland Security / Military
Detection of Explosives & Fissile Material in Cargo or Luggage
Chemical Analysis of Questionable Contents
Land Mine Detection
Shipping Container Evaluation
Narcotics Detection

15. Compliance with the GALL Report
Nuclear Industry
Compliance with the GALL Report
NUREG-1801 (2010)
Measuring Radiation Structural Damage
Containment Vessels
Cooling Pools
Pipes

16. Generic Aging Lessons Learned (GALL)
Nuclear Industry
Generic Aging Lessons Learned (GALL)
The GALL report evaluates existing programs for providing structural and component safety in Nuclear Power Plants. As these plants age and come up for renewal the GALL report facilitates the renewal process.
Its focus is on the staff review on the augmented existing programs for license renewal. Incorporation of the GALL report into NUREG-1800 and 1801 improves efficiency of the license renewal process.

17. Mining & Drilling Oil Well Logging
On-Line Assaying of Materials i.e. Coal, Cement, etc
Borehole Logging
Fuel Reprocessing
Mining of a Wide Variety of Minerals

18. Medicine Neutron Radiography Neutron Spectroscopy
Neutron Brachytherapy
Boron Neutron Capture Therapy (BNCT)

19. Civil, Aeronautical, & Nautical Engineering
Structural Inspection
Gas & Oil Tank Walls
Bridge Integrity
Airplane/Ship Components
Piping

20. Research Laboratories
Material Science
Nano Technology
Non-Invasive Analysis

21. Specifications for JNG-2 & JNG-3
JNG-2 DD & DT
JNG-3 DD & DT
Neutron Output:
105 n/s using D-D
107 n/s using D-T
106 n/s using D-D
108 n/s using D-T
Neutron Energy
2.45 Mev using D-D
14 MeV using D-T
Cooling System
Air Convection
Voltage
45kV
65kV
Current
2mA
5mA
Power Consumption
90 W
325 W
Maximum Input Power
250 W
Length
65 cm
Diameter
13 cm
Total Weight
13 kg
Projected Lifetime
3-5 Years with Option to Refuel and Service at End Time

22. Replaces Need for 252Cf Sources & Other Radioisotpe Sources
Safer to Operator
Safer to the Public
Eliminates Storage Issues of Source Material
No risk of theft of radioactive material

23. Additional Benefits of the JNG-2 and JNG-3
Ideal for Calibrating Neutron Detectors for Spontaneous Fission Neutrons
Calibrate Neutron Detectors for Higher Energies Including AmBe when Energy Correction Factor is established
JNG-2-DT Produces 14.1 MeV Neutrons and is available as a Neutron Interrogator

24. Certification
This instrument has been tested and certified by independent university tests at the University of Sydney, Australia

25. Neutron Generators Table 1.1 and 1.2
Neutrons, Nuclei and Matter; An Exploration of the physics of Slow Neutrons
By James Byrne (1994)