Diamond Sensor For The Neutron Electric Dipole Moment Experiment

Experiments planned to better constrain the value of the neutron electric dipole moment will test the standard model of physics and thereby contribute to DOEs mission to understand the fundamental forces and particles of nature as manifested in nuclear matter. These experiments take place in an interaction region where the magnetic and electric fields must be precisely controlled. It is a challenging environment, because access to the interaction region is limited, the temperature approaches absolute zero, and the sensors must cause minimal perturbations to the fields. This Phase II STTR project will further develop an all-optical measurement technique that can monitor fields without perturbing them and can operate at cryogenic temperatures, and thus could monitor the fields in the interaction region while the experiment is in progress. The overall goal is to develop an all-optical monitor based on diamonds doped with nitrogen, then processed to create nitrogen-vacancy centers. The magnetic and electric fields change the spectroscopy of the centers. Optical fibers bring light to and from the diamond. The Phase I research developed several fiberized sensor designs. One design was tested at low temperatures and shown to be robust. The optical noise associated with the design was shown to be low. Intellectual property developed includes a method for reducing effects from laser speckle and a proprietary sensor design. The Phase II project will produce a number of sensors based on the best designs. They will be tested for magnetic signature, modeled for electrical signature, and used to measure magnetic and electric fields. The optical design will be packaged and software will be developed to make a turn-key device. The sensors will be tested at a neutron electric dipole facility. Commercial Applications and Other Benefits: Successful completion of Phase II will result in a sensor with a unique combination of sensitivity and electro-magnetic inertness. Other physics experiments could benefit, as could particle accelerators. Further development may lead to additional sensors for medical and industrial applications.