Bubble chambers have emerged as promising detectors for WIMP (Weakly Interacting Massive Particles). Other similar detectors (Geyser and SDD- Superheated Drop Detectors) are used with the same aim. The seminar will concern on the description of such detectors and the principal source of background (gamma rays, neutrons and alpha particles). The status of a Geyser in construction in MILANO-BICOCCA, will be descibed.