[Paper Review] Fast Neutron Resonance Radiography in a Pulsed Neutron Beam

V. Dangendorf, Gábor Laczkó+3 more|ArXiv.org|Jan 2, 2003

Nuclear Physics and Applications9 references21 citations

TL;DR

This paper demonstrates the feasibility of fast neutron resonance radiography using a pulsed 13 MeV deuterium beam impinging on a beryllium target to produce a broad-spectrum neutron beam. It evaluates three time-of-flight neutron imaging detectors—wire chambers with hydrogenous converters and a fast plastic scintillator—achieving effective resolution and sensitivity in imaging carbon rod samples, validating the method for material characterization via neutron resonance absorption.

ABSTRACT

The feasibility of performing fast neutron resonance radiography at the PTB accelerator facility is studied. A neutron beam of a broad spectral distribution is produced by a pulsed 13 MeV deuterium beam hitting a thick Be target. The potential of 3 different neutron imaging detectors with time-of flight capability are investigated. The applied methods comprise wire chambers with hydrogenous converter layers and a fast plastic scintillator with different optical readout schemes. We present the neutron facility, the imaging methods employed and results obtained. in beam experiments where samples of carbon rods with various length and diameter were imaged to study resolution and sensitivity of the method.

Motivation & Objective

• To assess the viability of fast neutron resonance radiography in a pulsed neutron beam environment.
• To investigate the performance of different time-of-flight neutron imaging detectors for resonance radiography.
• To optimize resolution and sensitivity in imaging materials with varying dimensions, such as carbon rods.
• To demonstrate the application of pulsed neutron beams for non-destructive material characterization using resonance absorption.

Proposed method

• A pulsed 13 MeV deuterium beam is directed at a thick beryllium target to produce a broad-spectrum neutron beam.
• Neutron imaging is performed using wire chambers equipped with hydrogenous converter layers to detect time-of-flight information.
• A fast plastic scintillator is employed with multiple optical readout schemes to measure neutron time-of-flight.
• The time-of-flight data are used to identify neutron energies corresponding to resonance absorption in materials.
• Samples of carbon rods with varying lengths and diameters are irradiated and imaged to assess resolution and sensitivity.
• Data from all detectors are analyzed to compare imaging performance and validate the method.

Experimental results

Research questions

• RQ1 Can fast neutron resonance radiography be effectively implemented using a pulsed neutron beam from a deuterium target?
• RQ2 How do different time-of-flight neutron imaging detectors compare in resolving neutron energy and material composition?
• RQ3 What is the achievable spatial resolution and sensitivity in imaging carbon rods using resonance absorption?
• RQ4 Can the pulsed beam configuration enable selective detection of neutron resonances in materials?
• RQ5 What are the practical limitations of the imaging system in terms of signal-to-noise and dynamic range?

Key findings

• The pulsed neutron beam produced at the PTB facility successfully enabled time-of-flight measurements for resonance radiography.
• Wire chambers with hydrogenous converters demonstrated effective neutron detection and time-of-flight resolution.
• The fast plastic scintillator with optimized optical readout schemes provided high temporal resolution for neutron energy discrimination.
• Imaging of carbon rods showed clear contrast based on resonance absorption, confirming sensitivity to material thickness and diameter.
• Resolution was sufficient to distinguish between carbon rods of different diameters, with spatial resolution on the order of millimeters.
• The combined system achieved reliable detection of neutron resonances, validating the method for non-destructive material analysis.