be captured in the measurement trap. Cooling these ion beams, particularly radioactive ion beams, has been shown to drastically improve the accuracy and sensitivity of mass measurements by reducing the phase space of the ion collections in question. Using a light neutral background gas, typically helium, charged particles originating from on-line mass separators undergo a number of soft collisions with the background gas molecules resulting in fractional losses of the ions' kinetic energy and a reduction of the ion ensemble's overall energy. In order for this to be effective however, the ions need to be contained using transverse radiofrequency quadrupole (RFQ) electric fields during the collisional cooling process (also known as buffer gas cooling). These RFQ coolers operate on the same principles as quadrupole ion traps and have been shown to be particularly well suited for buffer gas cooling given their capacity for total confinement of ions having a large dispersion of velocities, corresponding to kinetic energies up to tens of electron volts. A number of the RFQ coolers have already been installed at research facilities around the world and a list of their characteristics can be found below. List of facilities containing RFQ Coolers See also Quadrupole mass analyzer References Bibliography External links LEBIT Project NSCL/MSU ISOLTRAP Experimental Setup TITAN: TRIUMF's Ion Trap for Atomic and Nuclear science TRIMP – Trapped Radioactive Isotopes: Micro-laboratories for fundamental Physics The SHIPTRAP Experiment The ISCOOL project Measuring instruments Mass spectrometry Accelerator physics