Dosimo

Meet Dosimo, a radiation badge who keeps count of how much energy soaks into each kilogram.

When radiation passes through matter, some of its energy is absorbed. What matters for damage is not the total energy but how concentrated it is. The absorbed dose is the energy deposited per kilogram of material, D = E/m.

The unit is the gray, where 1 Gy is 1 joule per kilogram. If a 70 kg person absorbed 0.14 J spread evenly through the body, the dose would be 0.14 / 70 = 0.002 Gy, or 2 mGy. That is a very small amount of energy, far too little to warm you, yet radiation delivers it in concentrated bursts that can damage cells.

Different radiations do different amounts of harm for the same dose, so health physicists also use a weighted dose measured in sieverts.

Workers in hospitals, laboratories and nuclear plants wear dosimeter badges like Dosimo so that their exposure is tracked and kept safely below set limits.