Low profile ionization chamber

An ionization-type smoke sensor comprising:

• a housing having an over-all exterior height of less than 2 cm and an internal volume;
• a source of alpha particles carried within the housing wherein the particles exhibit a mean travel distance therein less than 2 cm and generate in excess of 5 ion pairs per micrometer along a portion thereof.

An ionization chamber comprising:

• a housing having first and second ends and wherein the housing defines an internal volume;
• a sensing electrode carried by the housing wherein the electrode has a conical cross-section that extends into the housing a source of alpha particles carried within the housing wherein the source exhibits an energy level of less than 4 MeV and wherein the particles exhibit a mean travel distance therein less than 2 cm and generate in excess of 5 ion pairs per micrometer along a portion thereof.

An ionization-type smoke detector comprising:

• a housing having an over-all exterior height of less than 2 cm and an internal volume;
• a source of alpha particles carried within the housing wherein the source exhibits an energy level of less than 4 MeV and wherein the particles exhibit a mean travel distance therein less than 2 cm and generate in excess of 5 ion pairs per micrometer along a portion thereof.

An ionization-type smoke detector comprising:

• a low profile-type chamber having an internal particle travel distance of less than 2.5 cm;
• an ion source carried within the chamber wherein the source has an activity level of less than 5 KBq and is selected from a class having an initial emission energy level less than 4 MeV and wherein the source emits particles in the chamber on paths corresponding in length to the internal travel distance.