RLL Source Holder

RLL: Ronan's Radiation Low Level Source

RLL is a Ronan Engineering term that stands for "Radiation Low Level." RLL technology utilizes up to a total of 0.9 mCi (0.33 GBq) of cesium source. In comparison, some conventional density gamma gauges use source sizes with a hundred times more activity to make the same measurement. Because of these very low-levels of activity, and their simplicity of design, Ronan systems are the safest gamma gauges on the market. The NRC recognized this in 1999 when Ronan Engineering attained certification for the first RLL source design. 

Three types of RLL Source Holders: the RLL-1, RLL-1A, and RLL-2. 

  • RLL-1: one-ten 0.09 mCi (0.003 GBq) cesium capsules
  • RLL-1A: single 0.90 mCi (0.03 GBq) cesium capsule
  • RLL-2: strip source holder which accommodates up to a total of 100 µCi (0.004 GBq) cesium 137

The RLL-1 and 1A are very similar in that neither require: 

  • Periodic shutter check. Per NRC guidelines, shutters are not required on source holders with less than 1 mCi (0.037 GBq) of cesium.
  • No Radiation Safety Officer and/or Special Radiation Training is required by NRC
  • No licensed radiation personnel is required to install, commission or move on-site

Other advantages include: 

  • 0.5 mrem/hr @ 12"
  • Lower disposal cost than conventional, higher intensity type gauges
  • Lead free option available
  • Fire resistant design available 
  • Less risk to users
  • Less documentation to maintain

RLL-1 does not require a Leak Test. RLL-1A requires a Leak Test very three years. 

Ronan sizes the source to last a minimum of 15 years, usually 20-30 years.  Our goal is to provide a minimum of 15 years of service on all source. 

Cost of Ownership 

Even though the initial equipment cost may be approximately 10% higher than conventional gamma gauges, the return on investment is almost immediate.  The differential in equipment costs are offset by lower installation costs (RLL sources do NOT require licensed personal to install, commission or move them… conventional sources require licensed personal.)  On-going maintenance costs are also lower as the RLL does NOT require periodic leak tests (RLL-1) or shutter checks as conventional sources do.

  • The RLL Type Gauge is Approximately 100 lbs (45 kg), Lighter Than Conventional Type Gamma Gauges and as Such are Easier to Install...No Supports Required on Smaller, Lighter Piping
  • The RLL is Smaller in Overall Dimensions (6 in, 15 cm) Than Conventional Type Gamma Gauges
  • Dependable, Reliable, Repeatable Measurement That is Easy to Install, Calibrate and Maintain

Ronan can utilize low-level technology because our only focus is on non-contact measurement gauges. We use extra sensitive scintillation type detectors.  We cut and polish the crystals at our facility.  We utilize spring pressure to hold the crystal securely to the photo-multiplier tube.  We do not use cements, glue or grease that can degrade or break the connection between the crystal and photo-multiplier tube.  Ronan typically uses larger crystal sizes, which enables us to measure a larger sample of the product in the pipe. Ronan’s microprocessor utilizes the latest technology in the industry.


RLL Source Holder Spec Sheet



Sitemap | Contact Us

Copyright © 2013 Ronan Engineering Company. All Rights Reserved.