Compact Electronic X-ray Source for Borehole Logging

Gamma-ray sources are currently used in well logging for densitometry and lithology among other applications. These sources typically employ radioactive sources such as 137Cs, which presents a significant safety and proliferation hazard due to its long half life (30 years). Furthermore, these sources typically use cesium chloride, a water-soluble crystalline salt, which makes them particularly dangerous in a radiological dispersion device (“dirty bomb”). These concerns limit the applicability of gamma-ray logging due to the limits imposed on the source. Technical Approach This project will develop an innovative, ultra-compact, cm-wave linear accelerator with a novel microwave power source, both of which will be 3” in diameter to fit into even the smallest of production casings. The proposed eXtra Compact Linac (XCL) tool consists of a rugged system containing a novel microwave RF source serving also as the electron injector for a novel, cm-wave accelerating structure. Insensitivity to the harsh environmental conditions is achieved by using wide bandwidth, brazing-free, copper-coated ceramic structure. Phase I Plans In Phase I, the XCL system will be designed and feasibility to replace as much as 2.5Ci of 137Cs will be demonstrated. A mockup of the key, high-risk elements of the system – the generating/accelerating structure – will be experimentally tested. Commercial Applications and Other Benefits The borehole logging industry will grow from an estimated $15.58 billion in 2014 to reach $25.46 billion by 2019. Using a bottom up sizing approach, RBS estimates the initial market for replacement borehole logging equipment totals 1,000 units. With an average selling price of $300- 400k per unit, RBS estimates the replacement market to be $2 billion. In addition to the potential commercial success of this product, the XCL will improve the safety of oil exploration activities and reduce the risk of diversion of radioactive sources for terrorist purposes. Key Words: Cs-137, radioisotope replacement, borehole logging, linear accelerator, linac, RF, microwave.