Precision scan-imaging for paperboard quality inspection utilizing X-ray fluorescence

• Paperboard is typically made up of a core of cellulose fibers [C6H10O5] and a coating layer of [CaCO3]. The uniformity of these layers is a critical parameter for the printing quality. Current quality control methods include chemistry based visual inspection methods as well as X-ray based methods to measure the coating thickness. In this work we combine the X-ray fluorescence signals from the Ca atoms (3.7 keV) in the coating and from a Cu target (8.0 keV) placed behind the paper to simultaneously measure both the coating and the fibers. Cu was selected as the target material since its fluorescence signal is well separated from the Ca signal while its fluorescence's still are absorbed sufficiently in the paper. A laboratory scale setup is built using stepper motors, a silicon drift detector based spectrometer and a collimated X-ray beam. The spectroscopic image is retrieved by scanning the paperboard surface and registering the fluorescence signals from Ca and Cu. The exposure time for this type of setups can be significantly improved by implementing spectroscopic imaging sensors. The material contents in the layers can then be retrieved from the absolute and relative intensities of these two signals.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

Nyckelord

Inspection with x-rays

Spectrometers

X-ray fluorescence (XRF) systems

Calcium

Calcium carbonate

Calcium compounds

Coatings

Inspection

Paperboards

Stepping motors

Thickness measurement

Fluorescence signals

Paperboard surfaces

Relative intensity

Silicon Drift Detector

Spectroscopic images

Spectroscopic imaging

Visual inspection method

X ray fluorescence

Fluorescence

Image Analysis

Paper Boards

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)