Medical department of uatl® private
research university
calibrated neutron flux scanning technology for real-time recognition of the composition of substances
at the molecular level
results:
1. SEM (Sensor Element) scintillator has the capability to convert alpha,
beta, x-ray and gamma radiation to photons. In addition, a further
version of SEM is also designed to convert neutrons.

2. SEM is rugged by design and can take vibration and shocks without
any effect. It is also not hygroscopic and therefore humid environments
will not affect its performance or life time.

3. System is four times more efficient at signal collection than a
traditional method.
01 HOW IT WORKS
1. Radiation source emits ioizing radiation. The radiation can be any of of a mix of gamma, x-ray, neutron, alpha or beta radiation.
2. The radiation encounters the SEM.
3. The SEM converts the radiation to photons.
4. Readout and preprocessing component reads and converts the signal to a digital format.
5. The signal is transferred to the processing board for analysis.
6. The resulting data of the analysis is transferred to a client device via chosen bus.
02 Dual neutron and X-ray detection
The RADSCAN radiation detector is a double sided semiconductor sensor operating in real time and registering simultaneously and independently both X-rays and neutrons. One part of the detector responds to neutrons but not to X-rays and the other part detects X-rays but is transparent to neutrons.
As an electrically neutral nuclear particle, neutron interacts with matter via nuclear force, i.e. it “senses” the atomic nuclei directly. X-ray interact primarily through electromagnetic force, and are affected by the atomic electrons, and consequently by the atomic number Z of the medium. An illustration of the absorption probability of X-rays and neutrons is shown in Figure 2, where the size of the circle indicates the absorption strength of a given material vs. type of incident radiation. While the larger-Z materials absorb the X-rays most effectively, it is the low-Z materials that have the highest conversion probabilities for the neutrons.

Absorption probabilities of different materials for X-rays (yellow circles) and neutrons (blue circles). The larger the circle, the stronger the absorption (i.e. detection).
Neutron radiography image of a film camera (a) and X-ray radiography (b). The neutron radiography can better reveal plastic parts (light elements) of the camera and the metallic pieces are transparent for neutrons.

The situation is opposite with X-rays which show the metallic parts with a better contrast.
03 Limitations of detection technologies in the market:
1. Can only detect dense targets (drugs, chemical weapons are undetected)
2. Illegal targets can be shielded by denser material, such as lead
3. High positive false alarm rate (no threat but alarm)
4. High negative false alarm rate (threat but not detected)
5. High energy X-ray systems is not safe for humans
Solution/ technology
Advantages
Disadvanages
X-ray
detector
- low cost
- standardized system
- high positive false alarm rate (no threat but alarm)
- high negative false alarm rate (threat but not detected)
- high X-ray rate is not safe for humans
- can only detect dense targets
- Illegal targets can be shielded by denser material, such as lead.
Gamma-ray
detector
- standardized system
- safe to humans
- high cost due to the cost of cooling HPG
- average positive false alarm rate (no threat but alarm)
- average negative false alarm rate (threat but not detected)
- can only detect dense targets
- Illegal targets can be shielded by denser material, such as lead.
RADSCAN
detector
- minimal positive false alarm rate (no threat but alarm)
- minimal negative false alarm rate (threat but not detected)
- safe to humans
- can detect soft and dense targets
- not standardized system
- need development
CUSTOMER BENEFITS
No need for several detector types – one sensor platform for all radiation types
Can be uses in rugged environments – shock and vibration
resistant
Make is large or small – scalable area
Use it in humid and moist environments – non-hygroscopic
No danger of electric shocks – no need for high voltage
Can be used with batteries only – low power consumption