OVERHOFF TECHNOLOGY
Compact Neutron Generator
Technology
Models: JNG-2-DD/DT
&
JNG-3-DD/DT
---Robert Goldstein
Technical Associates,
North American Distributor
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

A Brief Overview
of
Neutron Sources

Intentional






Radioisotope sources
Photoneutron Sources
Accelerator sources
Nuclear reactors
Spallation sources
Neutron generators
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
0.7 x 10-4
242Cm+Be
6.11
163 days
1.1 x 10-4
241Am+B
5.48
2.44 x 10 4 years
1.0 x 10-5
241Am+F
5.48
2.44 x 10 4 years
4.0 x 10-6
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+D O
2
2.757
15.1 h
7.3 x 10-6
72Ga+D O
2
2.51
14.3 h
1.9 x 10-6
124Sb+Be
1.691
60.9 days
5.1 x 10-6
140La+Be
2.51
40.2 h
0.08 x 10-6
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.
A Brief Overview
of
Neutron Sources

Intentional

Nuclear reactors and Spallation sources
Are beyond the scope of this presentation.
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
3.26 MeV
 D + 3H --> 4He3 + n
17.6 MeV
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

JNG-2 – Neutron Generator
Benefits:





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Portability
Reduced Power Input Requirements
Increased Neutron Output
Adaptable for Tailoring to Specific
Customer Needs.
Reduced Manufacturing Costs
High Reliability and Long Operating Life
Applications:
Non-Destructive Testing






Homeland Security / Military
Nuclear Industry
Mining and Drilling
Medicine
Civil, Aeronautical, & Nautical Engineering
Research Laboratories
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
Varies
65 cm
Weight
33 lbs – 362 lbs
28 lbs
Operation
Deuterium – Deuterium – DD
Deuterium – Tritium - DT
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
Neutron Generator – Basic Process
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
Nuclear Industry

Compliance with the
GALL Report
NUREG-1801 (2010)
Measuring Radiation Structural
Damage
Containment Vessels
Cooling Pools
Pipes

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.
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
Medicine




Neutron
Radiography
Neutron
Spectroscopy
Neutron
Brachytherapy
Boron Neutron
Capture Therapy
(BNCT)
Civil, Aeronautical, & Nautical Engineering

Structural
Inspection




Gas & Oil Tank
Walls
Bridge Integrity
Airplane/Ship
Components
Piping
Research Laboratories



Material
Science
Nano
Technology
Non-Invasive
Analysis
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
2.45 Mev using D-D
14 MeV using D-T
Cooling System
Air Convection
Air Convection
Voltage
45kV
65kV
Current
2mA
5mA
Power Consumption
90 W
325 W
Maximum Input Power
250 W
250 W
Length
65 cm
65 cm
Diameter
13 cm
13 cm
Total Weight
13 kg
13 kg
Projected Lifetime
3-5 Years with Option to
Refuel and Service at End
Time
3-5 Years with Option to
Refuel and Service at End
Time
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
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
Certification
This instrument has been tested and
certified by independent university tests at
the University of Sydney, Australia
Neutron Generators
Table 1.1 and 1.2
Neutrons, Nuclei and Matter; An Exploration of
the physics of Slow Neutrons
By James Byrne (1994)