Gamma-Ray Inspection System

The most important tool any inspector can have is a sharp eye. To compliment this tool in manual inspections, fiber-optic scopes, hydraulic jacks, wet and dry vacuums, torches, magnesium arc cutter, chainsaws, drills, electronic stethoscopes, and many other common and specialized tools are utilized. It is unlikely that these tools differ too much internationally.

IG-SCAN MODELS

There are three types of Inspection Systems available:

• IG-SCAN Fixed Inspection System

• IG-SCAN Mobile Inspection System

• IG-SCAN Moveable Inspection System

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Comparison of Gamma Ray via X-Ray Container Cargo Scanning System

Faced with an ever-growing concern over port security and few choices available using standard x- ray technologies, port officials and customs agencies are looking for other solutions. Their search has led them to a new technology: one which replaces expensive, complicated and often methods and sources were not providing a cost-effective solution for large-scale container inspection operations. Being expensive, slow, difficult to operate and maintain and existing largely in permanent structures, these x-ray based inspection systems faced a number of obstacles. Over the last five years many research and development have addressed these cost and performance issues by applying decades of high-resolution industrial imaging experience towards the development of an innovative system that combines the best that gamma-ray and x-ray technology has to offer.

Since then, gamma-ray technology has proven itself to be a fast, reliable, effective and inexpensive way to identify and deter the contraband transportation business. These have led to a family of high-throughput inspection systems. IG-SCAN is able to evaluate containers without impeding commerce with constrictive, time-consuming choke points. These new IG-SCAN products are reconfigurable, self-powered, inexpensive and easy to use and maintain, making them ideal for permanent, temporary or mobile inspection stations.

Because they use commonly available isotopes and used widely in numerous industrial applications, Gamma-ray sources represent a more practical, cost-effective and safer alternative to current x-ray based inspection systems. Here, we report on the advantages of this new gamma-ray technology while keeping a close eye on the concerns of the ports and their business partners.

THE GAMMA-RAY ADVANTAGE

Because they use commonly available isotopic sources, gamma-ray systems are able to provide greater inspection capability while eliminating the need for large, costly, high-maintenance x-ray sources and accelerators. IG-SCAN’s ability to eliminate the need for an x-ray source opens up a myriad of advantages for the gamma-ray system. Gamma-ray sources provide a highly penetrating fan beam of gamma rays using a single energy. These gamma rays have a much higher effective energy than commonly used x-ray sources. This higher energy translates to superior penetration and single-energy output of the source results in a sharper image. Higher energy x-ray sources are available from some manufacturers; however, these sources are extremely expensive and very difficult to maintain and operate. In general, gamma-ray based inspection systems can be made smaller, faster, safer and easier to use. They require less power, little or no infrastructure, are easier to maintain and repair and are far more economical. When evaluating an inspection system, we need to keep in mind the Performance, Practicality, and Price.

PERFORMANCE: SMALLER, FASTER AND SAFER

By using a gamma-ray source the need for large accelerator-based or electronic x-ray sources is eliminated.
Eliminated also are the accompanying power and control systems, permanent shielded building and large container conveyor system. This makes gamma-ray systems far smaller than their x-ray based counterparts.
Real estate on port facilities is a valuable commodity, and every port already dedicates an area to processing container traffic. IG-SCAN’s gamma-ray inspection systems are designed to fit within the existing infrastructure of the port without the need for the kind of dedicated space required of an x-ray inspection system. In addition, many ports are now, or will soon be, undergoing major reconfigurations in order to keep up with increased container traffic. The economy of a gamma-ray system allows it to be disassembled, moved and reassembled in one or two days.

Because gamma-ray detectors are inherently more sensitive than x-ray detectors, a gamma-ray based system essentially captures more data, much faster than x-ray systems. In fact, in terms of speed and throughput, a gamma-ray system is the only practical method of achieving 100% container inspection. While comparable x-ray based systems take only minutes to scan a container, the entire inspection cycle time can be 7-15 minutes. This translates to less than 100 vehicles per day. In contrast, gamma-ray based systems can scan a standard 40-foot container in as little as a few seconds, with an inspection cycle time of less than a minute. This leaves the flow of commerce at the port unhindered by the inspection process, an important consideration for port customers. The operation in Cambodian is now scanning over 200 containers per day.

Operator safety is another important issue in operations where port personnel and transportation workers are involved. The advantage of using standard gamma ray detectors lies in their ability to count individual gamma-rays. This greatly diminishes the need for the extremely intense inspection beams used by other systems. IG-SCAN’s gamma-ray systems require only a small amount of localized shielding to minimize exposure and maintain extremely high levels of protection. Gamma-ray sources used in these inspection systems are commercially available and are widely used in industry and distributed internationally. They have been leak-tested, drop-tested, fireproofed and registered and certified by the Chinese Nuclear Regulatory Commission. IG-SCAN’s systems require no specialized expertise, training or precautions to use or maintain them.

PRACTICALITY: SIMPLE AND RELIABLE

Virtually all of the components of a gamma-ray inspection system have a long track record of use and have been proven extremely reliable. There are four main components to any inspection system: the source, the detectors, the computer and the infrastructure. The gamma-ray source, as described above, is found in calibration equipment used world-wide and has an operational lifetime of 10-15 years. The effective energy of an x-ray source is typically two-thirds of its rated maximum energy.

The system incorporates weather resistant stainless steel and anodized aluminum parts and requires no large building or dedicated utilities. In fact, the entire system can be operated with a small portable generator out of a modest trailer or enclosure. The gamma-ray system design is based on proven technologies, a minimum of moving parts, easily replaceable components and a simple software operating environment. This all adds up to reduced training time, installation costs, operating costs, and maintenance and repair time.

PRICE: THE COMPLETE PICTURE

The simplicity and reliability of a gamma-ray based inspection system make 100% container inspection available at a fraction of the cost of conventional x-ray systems. The first cost saving is realized in the ‘up front’ cost of the equipment itself. X-ray systems, due to the much higher source and infrastructure requirements, generally cost anywhere from 3-20 times more than a gamma-ray based system, depending on the configuration. Installation also runs 4-5 times higher due to the necessity to reconfigure the port traffic flow and in providing power and other utilities services. Beyond that, operational costs for x-ray systems include higher utility bills, more personnel, and increased maintenance and training requirements. Repair costs are another hidden expense that can be formidable when complicated x-ray sources start having problems. Of course, relocating or reconfiguring the inspection station is often impossible with an x-ray system due to fixed shielding, foundations and utilities, while a gamma-ray system is easily moved and reconfigured in a day or so. Given that the average throughput of a gamma-ray system is up to 10 times greater than even the fastest x-ray system, the overall cost on a per inspection basis for a gamma-ray system can be 50 times lower than using conventional x-rays.

MODULARITY AND CUSTOMIZATION

The modular design of the three main components, the source, the detectors and the computer system, allows each gamma-ray system to be tailored to meet each customer’s specific needs relating to operational considerations, image resolution and quality, inspection throughput, physical constraints, safety and environmental concerns and of course, cost. The source strength and penetration can be easily varied using different radioisotopes and activities. The shielding and shutter mechanisms are common to all source modules and thus simple to substitute, exchange or upgrade. The detectors are constructed in modular sections. Additionally, the number and size of the detectors within each module can also be varied as appropriate for the customer’s inspection requirements. A standard Pentium-based computer provides all the control needed to operate the entire system. The computer console’s hardware and software, while consisting of a standard set of components, can be customized with peripherals as necessary.
 

 IG-SCAN GAMMA-RAY CONTAINER INSPECTION SYSTEMS

The IG-SCAN-2000 Container Inspection System has many excellent features. Its operation performance is excellent. It is easy to operate and maintain, also safe and very reliable. One of the systems has operated for six month continuously without problem. The operating cost is comparatively much lower. The successful scanning rate is closed to 100% and the overall scanning speed is 3 minutes per container.

IG-SCAN-2000 Container Inspection System can be installed in the seaport, the river port, the air port, the railway station, the trading port, the developing area, the protective area and the hub of communications, etc. Quite obviously, it is a powerful means for combating smuggling, preventing terror and ensuring shipping safety.

IG-SCAN-2000 Container Inspection System is cost competitive and at the same time, its operating performance is very stable and rather convenient to maintain. A big gamma ray source of Cobalt-60 is equipped in the system to use for inspecting articles to be checked. Of course, gamma ray source is much cheaper in price than that of the same grade flux of accelerator and its energy is kept constant for long time, therefore there is no need for any ordinary maintenance during daily operation. The solid detectors installed in the system have high detection efficiency and many advanced features. They are very stable and reliable in the course of inspecting operation, steady and durable in the service life and anti-interference for their surroundings.

IG-SCAN-2000 is based on the patented technology of combining Cobalt-60 gamma ray source with solid detectors in the system. The Container Inspection System is made up of several units, such as sealed Cobalt-60 gamma ray source and its collimator, solid detectors and their electronic circuits, signal and image processing subsystem, platform trail and control subsystem.

During the course of the inspection, a beam of gamma ray emitted from the source is confined by the collimator to form a vertical narrow beam with a shape of slice. After penetrating the articles to be checked in the container, the beam of gamma ray is separately emitted into the solid detectors that are arrayed in the signal and image processing subsystems. Once detected, the beam of gamma ray is separately processed by its electronic circuit to obtain their respective image of the article shape loaded in the container. In this way, all the articles to be inspected in the container are continuously scanned by gamma ray as platform trailer subsystem is moving from the starting point to the end point at a constant speed till the inspecting work is completely finished. During the image scanning, one shape of the image showed on the screen of CRT can be transformed into the another by means of computer image processing techniques such as the local amplification of the images, the edge enhancement of the images, the zoom enlargement of the images, the adjustment pseudo color in manual, the fine details in the different order of the image, and etc.. In order that inspectors of customs are able to smoothly complete their checking process, the inspecting results and customs declaration will be processed and produced by computer and filed in electronic forms.

1. The energy of gamma ray emitted from the Cobalt-60 Source remains constant for long time, therefore the system is quite stable and reliable to operate.

2. Adopting Cobalt-60 source, there is no need for any adjustment and maintain, or suddenly stop the whole system in the daily operation for maintenance, thus the system can save a lot of expenditure on operation and maintenance, while the system with an accelerator have to run up to nearly millions of expenses of USD for its daily operation and maintenance per year.

3. The Cobalt-60 source is no need for any power to supply, because this is not a large scale devices, which need to supply much electricity for daily operation, consequently the interference suffered from high voltage and intensive noise of microwave can be avoided. That is why the system with cobalt-60 is much more stable and reliable than the system with an accelerator.

4. The radiation output emitted from Cobalt-60 Source is equal to about one over hundreds of the system with the old type of X-ray accelerator. Of course such a low radiation is very easy to protect.

5. Referring to the radiation dose that is received by the article in the container during inspection, it is only about 5μGy. Under the dose, an article like as photo films will not be in the least damaged.

6. The area occupied by the system is very small( only need some 1,000 m^{2 ),} while floor area of the system building is about 500 m2 and protection area is only 60 m2, thus the construction cost of the system is also quite low.

7. The total price of the system with Cobalt-60 Source is rather low,  that is equivalent to one fifth or one third of the system with accelerator.

A Comparison table of Cobalt-60  and with Accelerator

1. In comparison with the gas detector, the efficiency of the solid detector can be come up to over 80%, much more than that of the gas detector （only reaches ≤30%） and its imaging quality is also satisfying.

2. The solid detector is not suffered from any outside disturbing influence, such as temperature, pressure, humidity, electronic wave and mechanical force etc..

3. The solid detector that made of ruggedness material is not only easy to process but is not damaged in the operation life.

4. The working voltage of the solid detector is only 10 voltages and very easy to operate, whereas the gas detector which adopt as high as several thousands of voltage is tended to sparking and require to checking during operation.

5. The service life of the solid detector is estimated to be over 10 years and it is much longer than the gas detector.

A Comparison Between the Solid Detector and the Gas Detector

Any small articles those are secretly concealed in a big goods in a container can be detected immediately. The detectable thinnest limit of a iron wire that is placed behind 100mm thick iron plate in a container is 2.5mm in diameter.

• The contrast of high sensitivity

The articles loaded in a container are clearly showed its original shape. The detectable thickness limit of a iron plate that is placed behind 100mm thick iron plate is 0.7mm in thickness.

• The radiation of high penetrating power

All of the articles loaded in a container are clearly observed. Referring to some small articles, even if those are placed behind 230mm thick steel plate, the articles are still recognized what those are.

• The inspection of low dose

The dose received by an article during scanning is approximately the same amount of cosmic ray received during traveling by air for an hour. The maximum dose received by an article during scanning is only 5μGy.

• The throughput of high speed

It is a important factor for a inspection system to maintain high speed of inspection, especially for daily inspection in a large seaport. In the system with Cobalt-60, the maximum numbers of containers those are to be inspected per hour are 20, it is just the same numbers as the system with accelerator do.