Substance detection in the field requires high specificity, relatively inexpensive equipment, and good sensitivity.  Nuclear quadrupole resonance, a type of radio-frequency spectroscopy done at zero-field, gives high specificity and uses relatively inexpensive equipment; optically pumped atomic magnetometers, in place of conventional coil detection, provide the high sensitivity.   I will discuss how to manipulate the nuclear spin in the sample to extend the signal’s duration and the atomic spin in the magnetometer to quicken the magnetometer’s response time.   The negative feedback that enables this quickening also serves to suppress the quantum noise in the magnetometer.