|
|
|
|
|
 | Vehicle / Container Monitor |
| Pedestrian Monitor |
| Conveyor / Luggage Monitor |
If you want additional information, please fill out the information request form.
What is a Radiation Portal Monitor?
A radiation portal monitor is a detection device that provides a passive, non-intrusive means to screen cars, trucks and containers for the presence of nuclear and radiological materials. These systems are capable of detecting various types of radiation emanating from special nuclear materials, from natural sources, and from isotopes commonly used in medicine and industry. The deployment of portal monitors is an important component of a multi-layered strategy to prevent the introduction of nuclear and radiological materials into this country.
Are portal monitors safe? Do they expose people to radiation? Do they emit radiation?
Portal monitors do not emit ANY radiation. They are completely
safe for anyone passing by them, including children
and pregnant women. Again, portal monitors are passive
“detectors” of radiation, not emitters of radiation.
Portal monitors are used to ensure that radioactive
materials are not improperly moved from a facility
or transported illegally.
Portal monitors do not emit X-rays or other radiation. The portal monitor is a passive system that “reads” energy emitted by radioactive sources that happen to pass near it. The system is very similar to a radio receiver in that it responds to certain types of energy and provides an indication to the operator of the strength of the energy received.
What does it mean when a portal monitor alerts?
An alert by a portal monitor indicates that the device has detected a source of radiation passing by it. An alert by itself does NOT necessarily mean that a nuclear weapon or harmful radiation has been detected. There are many legitimate, “innocent” sources of radiation, including naturally occurring radiation and various medical and industrial isotopes that pose little threat to the public.
| Modular System Electronics |
| 1000 to 6000 cm2 neutron sensor configurations |
| 3x3” to 2x4x20” NaI gamma sensor or |
| 3800 to 76000 cm3 PVT gamma sensor |
| User Adjustable N/G Thresholds |
| Solid state glass fiber or He-3 gas neutron sensor |
| Separate neutron and gamma ray visible alarm |
| Medium or high level audible alarm |
| Over sampling of data intervals |
| Multiple integration times |
| Integrated PC104 Processor & computer connectivity |
| Independent or summed primary secondary operation |
| User or factory installation |
| Selectable count modes |
| Advanced shielding design |
| Transportable configurations |
| Universal power supply |
| Occupancy sensor (IR standard) |
| Tamper sensor |
| 1-Year manufacturers warranty |
| |
| Test for Moderated Neutron Source |
| Independent Software Settable Alarm Levels |
| Moving Average Background Calculation |
| Peak Detect Alarm Calculation |
| Remote Operation |
| ROI Method Provides High Sensitivity |
| Setup Parameter Security |
| Supervisor and Operator Display Modes |
| User Defined Alarm Conditions |
| Separate audio and video neutron and gamma alarms |
| Simple user interface |
| |
| Calculated net counts, emission rates and dose |
| Dose rate and dose rate warning |
| Graphical data presentation |
| Independent SW settable alarm levels |
| Nuclide identification option real time results |
| Occupancy counter |
| Separate audio and video neutron and gamma alarms |
| Setup parameter security |
| Status bar showing system diagnostics |
| Time series graphs and ROI graphical displays |
| Unlimited and automated daily LOG data files |
| Vehicle radiation profile side and top views |
| Video capture option |
| NaI(Tl) gamma spectrometer |
| Remote visible and audible Alarms |
| Service contracts and leasing program |
| Horizontal or vertical mounting structures |
| LogView SW for log file review |
| Video capture (up to 4 cameras) |
| Directional occupancy sensors |
| Ultrasonic or magnetic loop occupancy sensor |
| Color Inkjet Printer |
The modular design of the Nucsafe CRMS systems utilizes a radiation sensor panel or RSP. The RSP contains one or more neutron detectors made of a unique neutron-sensitive scintillating glass fiber (PUMA panels) or traditional He-3 pressurized gas tubes and one or more gamma ray detectors made of polyvinyl toluene (PVT) plastic scintillator or sodium iodide, NaI(Tl) detectors. The neutron detectors are surrounded by additional polyethylene moderator designed with MCNP to optimize the neutron response to a given source. The gamma ray detectors are shadow shielded with lead and / or steel to reduce their response from the side and behind the detector. The choice of detectors is typically a customer preference but there are advantages and disadvantages to each type of gamma ray and neutron detection technology.
For the neutron detectors, the PUMA fiber technology provide a solid-state alternative to conventional gas tube detectors. These detectors are less susceptible to vibration often encountered in harsh real world environments such a ports and toll booths and borders where large heavy trucks induce road vibrations. These detectors also distribute the neutron sensitive atoms uniformly over the entire active area of the detector providing a more uniform response to the radiation, important when measuring large objects at larger standoff distances due to the increased geometric efficiency. He-3 detectors are less expensive and provide good intrinsic efficiency for thermal neutrons. Both require proper moderator design for optimal performance.
For the gamma ray detectors, the choice between PVT and NaI(Tl) is based on cost and purpose. A smaller NaI detector can provide equivalent sensitivity to PVT because the energy resolution is much better providing improved signal to background particularly at higher energies. NaI detectors are required for Nucsafe's optional nuclide identification capability. These detectors are more expensive than PVT and when measuring large objects, the PVT plastic scintillator provides a larger geometric efficiency much the same as the neutron sensitive glass fiber does for neutron measurements. PVT is ideal for initial screening when only the presence or absence of radioactivity is needed.
The PVT gamma detectors use two photomultiplier tubes (PMT) to detect the light produced in the detector. The design of these gamma ray detectors maximize the sensitive volume of the detector and ensure uniformity of response over its active detection area. The user can select coincident or non-coincident operation for the 2 PMTs. Coincident operation provides the ability to reject non-coincident events resulting in a lower background. Our traditional electronics use six regions of interests (ROI) and a total gamma ray counting channel to separate the energies of the gamma rays providing improved signal to background and enhanced sensitivities. Our new gamma ray electronics use a 1024 channel multi-channel analyzer that allows overlapping regions of interest independently for each of the two channels, thereby providing both continuous energy ROI data and data for specific energy intervals such as ROIs around regions where naturally occurring radioactive materials (NORM) or special nuclear materials (SNM) filtering is required.
The electronics process the data calculating background, standard deviation and whether the measured data exceed a user-definable alarm set point. It is integrated into the NEMA4 or NEMA4X weatherproof enclosure and can communicate to a host computer up to 3000 meters away via RS-485 or even longer distance via Ethernet. The electronics are DC powered and contain both pulse processing electronics, calculations and communication for each of the RSPs. Data from each RSP can be polled as frequently as as every 50 msec providing over sampling of the radiation data for moving vehicles.
PUMA and PUMA Gold software can be installed on any Windows PC. With this software and an Ethernet connection, all monitoring information can be logged and viewed from a remote connection anywhere in the world . Management of multiple systems can be performed from a single PC.
The occupancy sensor is a device that senses the presence of an object (package, person, vehicle, container) in front of the radiation sensor panel. Nucsafe offers a choice of occupancy sensors including ultrasonic, active infrared and magnetic loop sensors. Ultrasonic sensors allow a single sensor to be used and works well in all weather condition including fog. Active IR sensors work well in most weather conditions and can detect both the presence of an object and its speed. With the IR sensor, Nucsafe offers a directional occupancy capability that allows traffic only moving in one direction to trigger the system alarm. This feature is useful when a single lane of traffic is available such as freight movement from a hangar at an airport. Two sensors are required for speed or directional measurements.
Nucsafe is the first and currently only company to offer real-time nuclide identification in a CRMS system. Using NaI detectors and whole spectrum fitting analysis, nuclide identification is reported within a second or two of the vehicle's passage. This option is well-suited at truck stops and inspection stations. Because of the high incidence of nuisance alarms caused by legal transport of NORM and TENORM materials as well as medical radionuclides, this capability reduces the secondary inspection frequency saving time and money.
| Dose rate display |
| Dose rate warning |
| Automatic nuclide identification capability |
Identifies shielded and unshielded sources. User selectable nuclide libary - 72 reference spectra of gamma nuclides are categorized based on their main practical occurrence:
Medical:I-131; Tc-99m; Ga-67; I-123; I-126; In-111; Pd-103;
Tl-201OSI:Ba-140; Cd-116; Ce-141; Ce-144; I-132; La-140; Mo-99; Nb-96; Nd-147;
Pr-144; Rh-106; Ru-103; Sb-125; Te-132; Xe-131m;
Xe-133; Xe-133m; Xe-135; Zr-95
Nuclear:Pu-239 ; U-233 ; U-235 ; Np-237
Industrial:Ag-110m; Am-241; Ba-133; Bi-207; Cd-109; Co-57;
Co-58; Co-60; Cs-134; Cs-137; Cr-51; Eu-152; Eu-155; Fe-59; Ir-192; K-40; Mn-54;
Na-22; Ra-226; Se-75; Th-232; U-238; Zn-65;
Ac-228; Ag-109m; Be-7; Bi-212; Bi-214; Ce-139; Hf-181; I-133;I-134; I-135;
Mn-56; Pb-214; Ru-106; Sb-124; Sb-127; Tl-208; Y-88;
Annihilation Radiation
The operator can select from 6 sub-libraries (Nuclear, Industrial, Medical, Customs, CTBTO, and User). All sub-libraries except CTBTO can be edited by adding or deleting specific nuclides from the list. Ten (10) reference spectra can be measured by the user and added to the predefined library spectra. Identification is done by a template matching correlation procedure.
False detection is when either a gamma-ray alarm is initiated by a neutron source or a neutron alarm is initiated by a gamma-ray source. The neutron detectors are insensitive to gamma radiation up to 500 mrad/h (5 mGy/h), gamma. The gamma-ray detectors are insensitive to neutron radiation up to 50,000 n/sec (neutron on contact). Estimated false detection rates in actual use is less than 1:100,000 alarms. Meaning, given 100,000 alarm conditions, only 1 will be misidentified as a gamma or neutron alarm.
CRMS software includes an automatic test sequence that forces the system into repeated occupancies and background update periods. The false alarm probability for both the gamma-ray channel and the neutron channel is better than 1:10,000 under normal test conditions (10 µR/h) and < 0.01 n/cm2/sec at sea-level (neutron). Background update algorithms adjust the background for diurnal and environmental changes. At alarm settings of five standard deviations over background, the system statistical alarm rate is 3 in 100,000 (1:30,000) as measured in the ITRAP program. The missed alarm rate at these same setting is less than 1:1000.
The CRMS design is modular and can be configured to meet any national or international sensitivity specification. Geometric sensitivity is scaled by adding or subtracting RSPs to a given CRMS system. Nucsafe CRMS system performance can be delivered to meet ASTM Category I, II, III, or IV SNM standards or ASTM Category NI, NII, or NIII SNM standards; or ANSI, ITRAP, IAEA, US Customs, and IEC requirements.
The sensitivity specifications presented here are for the nominal CRMS system, which is designed to meet ANSI N42.35, ASTM category II and NII (pedestrian), and US Customs specifications for portal monitoring systems (ref 6). Independent laboratory testing is still underway to certify sensitivity specifications. Sensitivity values are provided under the following test conditions:
| Background: Gamma-ray background of 10 µR/h |
| Background: Neutron background of < 0.01 n/cm2/sec |
| False alarm rate: no more than 1:1000 occupancies (gamma or neutron) |
| Source distance: closest approach to detector (0.5 meter pedestrian, 2.4 meter vehicle) |
| Source shielding: none |
| Source neutron moderation: none |
| Source travel velocity: 1.2 m/sec (pedestrian), 8 km/h (vehicle) |
| Source activity certified to ± 20% |
| Alarm probability of greater than 0.5 at a 95% confidence interval (ASTM C 1236-99) |
| Isotope or SNM | PEDESTRIAN (2 posts, 2-meter H) 0.5M distance |
VEHICLE (2 posts 4 meter H) 2M distance |
RAIL / CONTAINER (2 posts, 4 panels per side, 4-meter H) 4M distance |
| 57Co | 15 µCi | 30 µCi | 30 µCi |
| 133Ba | 8 µCi | 16 µCi | 16 µCi |
| 137Cs | 7 µCi | 14 µCi | 14 µCi |
| 60Co | 3 µCi | 4 µCi | 4 µCi |
| 228Th | 6 µCi | 7 µCi | 7 µCi |
| 241Am | 200 µCi | 450 µCi | 450 µCi |
| Neutron (252Cf) | 1.2E4 n/sec | 1.2E4 n/sec | 1.2E4 n/sec |
| HEU (ASTM) | 10 g | 800 g | 800 g |
| Pu (ASTM) - gamma | 0.3 g | 9 g | 9 g |
| Pu (ASTM) - neutron | 30 g | 180 g | 180 g |
Nucsafe’s Guardian Systems are certified as meeting the IAEA Illicit Trafficking Radiation Assessment Program requirements. Our actual performance exceeded these requirements in the laboratory tests. Nucsafe has also successfully participated in the DTRA / NSSA Unconventional Nuclear Warfare Defense Program run during 2002-2003.
|
