Precursor source arrangement and atomic layer deposition apparatus

A precursor source arrangement for an atomic layer deposition reactor for receiving a precursor container, wherein the precursor source arrangement comprises:

• a valve chamber including one or more valves;
• a precursor source chamber having a precursor container space inside the precursor source chamber for receiving the precursor container;
• a precursor source heat transfer element positioned at least partially within the precursor source chamber and arranged to heat the precursor container inside the precursor container space;
• and
• a valve chamber heat transfer element positioned at least partially within the valve chamber and arranged to heat the one or more valves inside the valve chamber, wherein
• the valve chamber heat transfer element and the precursor source heat transfer element are arranged in contact with each other such that the valve chamber heat transfer element is arranged in heat transfer contact with the precursor source heat transfer element and arranged to transfer thermal energy from the valve chamber towards the precursor source chamber.