# Modular and Cost-Effective Computed Tomography Design

## TL;DR

A modular and affordable gamma ray CT system is developed for studying multiphase flows in industrial equipment.

## Contribution

A cost-effective, modular gamma ray CT system with improved efficiency and flexibility for industrial applications.

## Key findings

- The system uses 16 scintillation detectors with 75% quantum efficiency and 10 × 10 mm2 active area.
- The design enables scalable scan times and simultaneous parallel beam projection acquisition.
- The system successfully upgrades existing setups for DN110 and DN440 columns with varying flow rates.

## Abstract

We present a modular and cost-effective gamma ray computed tomography system for multiphase flow investigations in industrial apparatuses. It mainly comprises a 137Cs isotopic source and an in-house-assembled detector arc, with a total of 16 scintillation detectors, offering a quantum efficiency of approximately 75% and an active area of 10 × 10 mm2 each. The detectors are operated in pulse mode to exclude scattered gamma photons from counting by using a dual-energy discrimination stage. Flexible application of the computed tomography system, i.e., for various object sizes and densities, is provided by an elaborated detector arc design, in combination with a scanning procedure that allows for simultaneous parallel beam projection acquisition. This allows the scan time to be scaled down with the number of individual detectors. Eventually, the developed scanner successfully upgrades the existing tomography setup in the industry. Here, single pencil beam gamma ray computed tomography is already used to study hydraulics in gas–liquid contactors, with inner diameters of up to 440 mm. We demonstrate the functionality of the new system for radiographic and computed tomographic scans of DN110 and DN440 columns that are operated at varying iso-hexane/nitrogen liquid–gas flow rates.