Carson Nuclear, LLC

Nuclear Security

Why Ludlum Measurements?

  • Credentials

    • Since 1962, Ludlum Measurements, Inc. has amassed a wealth of information, engineering knowledge, and manufacturing experience. We will help you implement the best radiation detection solution for your challenge.
    • Over 2500 RPM systems installed world-wide
    • Ludlum products have been evaluated and qualified by independent testing at:
           - National Institute of Standards
           - U.S. Department of Energy National Laboratories
           - Installations around the world
    • Designed to meet IAEA standards
    • Ludlum products have a demonstrated, high mean time between failure and a low mean time to repair.
    • Greater than 99.9% uptime. Ludlum RPMs have demonstrated MTBF of 8500 hours.
    • World-wide, world-class support
    • Privately owned, financially stable, vertical product manufacturer. Ludlum has direct control on technology, quality, cost, and supply chain.

    Click here for more information.
  • Qualifications

    Ludlum Measurements, Inc. is recognized as a world leader in the development and manufacture of radiation portal monitors. Tempered by time, independently tested and field proven, Ludlum systems deliver world-class performance. Ludlum is a vertically integrated manufacturer offering “off-the-shelf” gamma, gamma-neutron systems, and custom engineered solutions.

    • 1962 - Ludlum Measurements, Inc. incorporates. Today, Ludlum is a premier provider of radiation detection instruments and systems.
    • 1964 – Ludlum first patent, #3,122,635, issued on February 25th
    • 1975 – Governor’s Industrial Expansion Award, presented by the Honorable Dolph Briscoe, Governor of Texas, in recognition of a significant contribution to the economy of the State of Texas
    • 1975 – Larry Ludlum begins working with Ludlum Measurements, Inc. as an instrument designer.
    • 1983 - Ludlum enters the vehicle monitoring business after the accidental melting of a Co-60 source at a steel mill in Mexico.
    • 1996 - Ludlum purchases ADIT, a manufacturer of photomultiplier tubes, to guarantee a consistent and high-quality supply of these critical electronic components.
    • 1997 - Ludlum forms the subsidiary ELJEN Technology, to design and manufacture world-class scintillation detectors, thereby guaranteeing the highest consistency and quality of this major detector component.
    • 2002 - LMI was awarded the first major contract from the US Government for more than 300 gamma/neutron portal systems. The systems have been operating for eight years with less than 0.5% (2 days, ~8,500 MTBF), down time per system per year. LMI continues to work with the US government to upgrade and maintain these systems.
    • 2006 - Ludlum installs radiation portals in China. To date, approximately 25 systems have been installed along the borders and ports in China.
    • 2007 – Ludlum acquires Electron Tubes Limited, a photomultiplier tube manufacturer located in the United Kingdom.
    • 2010 –Supply of Helium-3 that is used in neutron detection becomes expensive and scarce. Ludlum develops a new neutron capable RPM series that are more cost effective than RPMs that are based on Helium-3 detectors.
  • Industry Regulatory Participation

    Ludlum Measurements, Inc. not only understands and meets the requirements of American National Standards; Ludlum participates in the development and approval of these standards.

    • ANSI N42.32: is the American National Standard Performance Criteria for Alarming Personal Radiation Detectors for Homeland Security. Dru Carson of Ludlum Measurements, Inc. was a member of the subcommittee N42.RPI (Radiation Protection Instrumentation).
    • ANSI N42.33: is the American National Standard for Portable Radiation Detection Instrumentation for Homeland Security. Dru Carson of Ludlum Measurements, Inc. was a member of the subcommittee N42.RPI (Radiation Protection Instrumentation) and a member of the ANSI 42.33 Working Group.
    • ANSI N42.34: is the American National Standard Performance Criteria for Hand-held Instruments for the Detection and Identification of Radionuclides. Dru Carson of Ludlum Measurements, Inc. was a member of the subcommittee N42.RPI (Radiation Protection Instrumentation).
    • ANSI N42.35: is the American National Standard for Evaluation and Performance of Radiation Detection Portal Monitors. Bill Huckabee and Mitchell (Mick) Truitt of Ludlum Measurements, Inc. were members of the ANSI 42.35 Working Group. Dru Carson of Ludlum Measurements, Inc. was a member of the subcommittee N42.RPI (Radiation Protection Instrumentation).
    • ANSI N323: is the American National Standard Radiation Protection Instrumentation Test and Calibration standard that establishes specific requirements for portable radiation protection instruments used for detection and measurement of levels of ionizing radiation fields or levels of radioactive surface contamination. Dru Carson of Ludlum Measurements is an active member of the committee responsible for the writing and revision of this standard.

    Licensing, Membership and Involvement

    • Licensed by the Nuclear Regulatory Commission of the United States
    • Licensed by the State of Texas
    • Health Physics Society (HPS)
    • Institute Of Scrap Recycling Industries, Inc. (ISRA)
    • International Nuclear Material Managers (INMM)
    • Individual Ludlum Employee Participation IEEE
  • Customer Reference Letter

    "Yes we have had a Ludum detector for years. About 3 years ago we installed a two panel model 4525. I own a scrap metal processing yard and we receive scrap from a variety of customers and on all types of vehicles. For this reason we did not put a three panel system in. I strongly believe having one overhead panel would be beneficial if you have a consistent size truck coming in. In a mill I suspect you would. We have been Ludlum customers for years and they are across the board a good group of people. Strong technical knowledge and very quick to help in any way. I can tell you that based on the tonnage we ship each year and the number of rejections we have had at the steel mill that the Ludlum system is accurate 99.5% or more. You will be very happy to have their system."

    Brian E.

    Click here to download a PDF of Ludlum's Qualifications


  • Common Challenges


    You might say, “I don’t know what that is, so I don’t have to worry about it.” Gamma radiation is found in a wide variety of forms and uses. Gamma radiation and gamma radiation sources are very beneficial to mankind. However, when used incorrectly or ignored, gamma radiation can also be a significant health risk or even deadly.

    Common Radiation Sources from Everyday Use

    • Old instruments from aircraft flight panels
    • Radium dial watches
    • Medical devices and materials
    • Industrial testing material
    • Smoke alarms

    Low Level, Shielded Source

    Sources that are intentionally or unintentionally shielded can go undetected.  The ability to detect very low levels of radiation helps guard against the radioactive source going undetected.  Radiation sources of primary concern:
    • Gamma
    • Neutron


    Naturally occurring terrestrial and extraterrestrial radiation are components of background radiation.  Environmental radiation can mask other, more dangerous radiation sources. Learn more about NORM.


    Radiation levels from a radiation source rapidly decline as the distance from the radiation source increases.  System designs that place the radiation detectors as close as possible to a subject under test to detect a low-level, shielded source are critical.


    Minimizing the time period required to detect the radiation source will maximize throughput.  A high throughput keeps commerce flowing, uninterrupted.

    Perceived Initial Cost of the System

    There have been several documented cases when complacency, lack of radiation knowledge, and not provisioning for the cost of detection has resulted in contamination and death on a very large scale.  The radiological accident in Goiânia, Brazil is one of the best documented examples of the real cost,  clean-up labor, equipment, disposal, lost real estate, and loss of life.
  • Gamma Radiation Detection

    Gamma Radiation Portal Monitors

    Ludlum's Model 4525 System Series Radiation Portal Monitors (RPM) offer a robust and field-proven technology for efficient gamma radiation detection. The system features large area PVT detectors and advanced algorithms that are key to detecting and locating gamma sources. The modular detector units are the building blocks used to address the different vehicle geometries to optimize successful detection and determination of the radioactive source location.

    These systems:
    • Are manufactured by Ludlum Measurements, Inc. using Eljen Technology's PVT
    • Include two photomultiplier tubes within each detector for 30% higher gamma sensitivity

    Typical Placement of Detectors

    Radioactive material can be shielded by various dense materials. Co-location of the RPM system with weight scales increases the effectiveness of the system. This aids the operator in determining if heavy, dense material is being used to shield a source.


    From Naturally Occurring Radioactive Material (NORM) to refined radiation sources, undetected sources of gamma radiation can be anywhere.  They can be intentionally concealed or innocently overlooked.  They can be easily detected or difficult to detect.

    Call Ludlum Measurements, Inc. today, so that together, we can define a radiation portal monitor solution to fit your requirements.  Click here for information on the Model 4525 System Series specifications.
  • Neutron Radiation Detection

    Model 4525-xxxxN System Series

    Ludlum's gamma/neutron Model 4525-xxxN systems are very effective in determining if neutron radiation sources are in their expected location. These Radiation Portal Monitors (RPM) enable the effective monitoring of neutron radiation movement.

    Detection & Shielding

    Detection and shielding for neutron radiation is very different than that used for gamma radiation.  In fact, for a given source of radiation, the gamma radiation or neutron radiation may be completely suppressed while the other radiation component goes unrestricted.  That is one reason why Ludlum Measurements, Inc. offers you gamma/neutron Radiation Portal Monitors in one, integrated system.

    Neutron Radiation Sources

    Neutron radiation sources are less common than gamma radiation sources and have very specific industrial or weapons applications.  The use of neutron radiation is not as common as the use of gamma radiation.  Naturally occurring neutron sources of any magnitude are almost non-existent.


    Ludlum gamma/neutron detection systems can be configured for governmental, industrial, and transportation applications or discrete indoor use, such as in airport or rail passenger areas.

    System Notification

    The Model 4525-xxxxN series systems provide a variety of alarms, alarm control, imaging solutions, and system diagnostics. The systems are designed for network integration.

  • Naturally Occurring Radioactive Material (NORM)

    Ludlum Measurements, Inc. has the expertise, experience, and instrument systems to help you with your NORM and TeNORM detection challenges.

    Naturally Occurring Radioactive Material (NORM) and Technologically-enhanced NORM (TeNORM) are becoming a subject of increasing scientific focus and regulatory action. NORM is comprised of all radioactive elements that naturally occur in our environment. Radioactive elements and their respective decay chains with long decay periods, such as Uranium, Thorium, and Potassium, present some of the most dominant challenges.

    Unwanted NORM and TeNORM contamination are characteristics of many different and widely distributed industrial processes. Industrial processes that involve oil and gas production, coal consumption, mineral sands, phosphates, Tantalum concentrate, and recycling are potentially challenged with NORM and TeNORM detection and disposition problems.

    For additional details, you should read the information contained in these PDF files.

    Potential Sources of NORM

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