The firm placing of 100m shares at 20p apiece was over-subscribed with new and existing institutional investors in the company taking part.
At the time of writing, Kromek's share price rose by nearly seven per cent.
Kromek provides digital colour x-ray and gamma ray detection and imaging that are used in security screening, civil nuclear and medical imaging markets.
The firm was spun out of Durham University in 2003 and listed on Aim in 2013 raising £15m to help fund expansion. At the time, the company was valued at £55m.
Peter Williams, chairman of Kromek, said: "The present fundraising will considerably strengthen our balance sheet, underpinning our plans for the sustained growth of the business and supporting increasing commercial activity through the deployment of our proprietary technology.
"Kromek has made good progress this year, in which we achieved a number of important operational targets, enlarging our customer base and strengthening our relationship with our OEM [original equipment manufacturer] partners. This resulted in significant contract wins over the past 18 months which have given us forward visibility over revenues in excess of 85 per cent of market expectations for the current year."