A modular sample processing apparatus kit comprising: a frame comprising a plurality of openings arranged in an annular array around a center of the frame; one or more process modules adapted to be retained within one opening of the plurality of openings in the frame, wherein adjacent process modules loaded into adjacent openings are separated from each other by a radial strut of the frame, and wherein each process module further comprises: a module body comprising first and second major surfaces; a metallic foil layer attached to the second major surface of the module body; a fluid structure in the process module, the fluid structure comprising an input well in fluid communication with a process chamber, wherein the input well is located radially inward of the process chamber relative to the center of the frame wherein the process chamber comprises a volume defined by a void formed through the first and second major surfaces of the module body and the metallic foil layer attached to the second major surface over the void in the second major surface; wherein the process chambers of the one or more process modules define an annular processing ring of the modular sample processing apparatus when the one or more process modules are retained within the plurality of openings in the frame; and wherein each process module comprises a z-axis thickness measured in a direction normal to the first and second major surfaces of the module body that is larger than a z-axis thickness of the portion of each radial strut of the frame located within the annular processing ring. a frame comprising a plurality of openings arranged in an annular array around a center of the frame; one or more process modules adapted to be retained within one opening of the plurality of openings in the frame, wherein adjacent process modules loaded into adjacent openings are separated from each other by a radial strut of the frame, and wherein each process module further comprises: a module body comprising first and second major surfaces; a metallic foil layer attached to the second major surface of the module body; a fluid structure in the process module, the fluid structure comprising an input well in fluid communication with a process chamber, wherein the input well is located radially inward of the process chamber relative to the center of the frame wherein the process chamber comprises a volume defined by a void formed through the first and second major surfaces of the module body and the metallic foil layer attached to the second major surface over the void in the second major surface; a module body comprising first and second major surfaces; a metallic foil layer attached to the second major surface of the module body; a fluid structure in the process module, the fluid structure comprising an input well in fluid communication with a process chamber, wherein the input well is located radially inward of the process chamber relative to the center of the frame wherein the process chamber comprises a volume defined by a void formed through the first and second major surfaces of the module body and the metallic foil layer attached to the second major surface over the void in the second major surface; wherein the process chambers of the one or more process modules define an annular processing ring of the modular sample processing apparatus when the one or more process modules are retained within the plurality of openings in the frame; and wherein each process module comprises a z-axis thickness measured in a direction normal to the first and second major surfaces of the module body that is larger than a z-axis thickness of the portion of each radial strut of the frame located within the annular processing ring.