The firm, whose technology is used for a variety of applications from medical imaging to security screening, sold 107m shares at 51p each. The offering raised £15m in an oversubscribed fundraising which valued the group at £55m.
The firm said it planned to use the proceeds for product development, expanding its sales team and manufacturing facilities as well as to pay off outstanding loans.
Durham University’s stake in the business is now worth around £3m.
Kromek chief executive Arnab Basu said he was “delighted” the flotation was oversubscribed.
“Kromek is ready to begin harvesting value by seizing the opportunities to sell our technology and products into the medical imaging, security screening and nuclear detection markets,” he added.
Panmure Gordon was both adviser and sole broker on the flotation.
Kromek is the latest in a flurry of floats on Aim with the London Stock Exchange revealing the number of companies admitted last month doubled to 14 compared to last year.