the search
What are the fundamental particles of our Universe? How do they interact? What are their properties? These are questions many physicists are working on today, yet we still are missing the answers to many of them. My research hopes to aid in shedding light on unsolved questions regarding the smallest fundamental particle in our Universe: the neutrino.
The Neutrino
beta decayWhen physicists started observing the inner workings of radioactive decay, a problem was discovered with the type of decay called beta decay. This decay results in the emission of an electron and the conversion of a proton into a neutron. However, the recoil of the nucleus and ejected electron did not conserve momentum all the time, and so a third particle to explain this range of energies an ejected electron could have was proposed in 1930 by a physicist named Wolfgang Pauli. This proposed particle later became known as the neutrino. |
Massive or Massless?For quite a while, the neutrino was assumed to be a massless particle. This changed with the discovery of neutrino oscillations. When a neutrino moves through space, it oscillates through different flavors, or types, and mass states. When we detect a neutrino, it is forced to take on one of these three flavors. These oscillations can only occur if the mass states are not all identical. Thus, the detection of these oscillations have led physicists closer to determining the actual values of the three mass states of the neutrino. Because of its small mass and weak interactions, the neutrino is incredibly hard to detect. |
Neutrinoless double beta decay and the demonstrator
One theoretical way to measure the mass of the neutrino is by observing a special type of decay called neutrino less double beta decay (0v2B decay). In order for this decay type to occur, the neutrino would have to be what is called a Majorana particle. This type of particle was postulated in 1937 by Ettore Majorana, an Italian physicist. These particles have strange properties such as being their own antiparticle. In 0v2B decay, only two electrons are emitted; the neutrinos that should be emitted in beta decay instead annihilate each other and are never detected. If this were to occur, the two electrons would have to carry away all the energy of the reaction.
Only certain materials can theoretically undergo this reaction. In the MAJORANA DEMONSTRATOR, Ge-76 is used as the source of events. The MAJORANA DEMONSTRATOR contains 30kg of Ge-76 and is situated in the Sanford Underground Research Facility in Lead, SD. Interestingly, Ge detectors are used to collect data so Ge is both the source and detector of our data. It uses p-type point contact Ge detectors for their high energy resolution and collects data as waveforms. The energy of the 0v2B decay reaction has been calculated and there would be a characteristic peak at 2039 keV should the decay be detected. Oddly enough, the decay rate of 0v2B decay could inform us about the mass scale of the neutrino. However, this reaction would be incredibly rare. In order to detect this decay, very low levels of noise in our data is needed for a few reasons. The first reason is that we do not want anything interfering with the small for which we are searching. If there were significant noise around 2039 keV, the signal may be missed entirely. Also, at the high energy range of 2039 keV noise has the effect of degrading our energy resolution. This would not allow us to as finely measure the energy of the 0v2B decay peak and would subsequently lead to more uncertainty in the calculated mass scale of the neutrino. For these reasons, noise monitoring and measurement are key to the operation of the MAJORANA DEMONSTRATOR.
More information on the MAJORANA DEMONSTRATOR can be found on their homepage.
Only certain materials can theoretically undergo this reaction. In the MAJORANA DEMONSTRATOR, Ge-76 is used as the source of events. The MAJORANA DEMONSTRATOR contains 30kg of Ge-76 and is situated in the Sanford Underground Research Facility in Lead, SD. Interestingly, Ge detectors are used to collect data so Ge is both the source and detector of our data. It uses p-type point contact Ge detectors for their high energy resolution and collects data as waveforms. The energy of the 0v2B decay reaction has been calculated and there would be a characteristic peak at 2039 keV should the decay be detected. Oddly enough, the decay rate of 0v2B decay could inform us about the mass scale of the neutrino. However, this reaction would be incredibly rare. In order to detect this decay, very low levels of noise in our data is needed for a few reasons. The first reason is that we do not want anything interfering with the small for which we are searching. If there were significant noise around 2039 keV, the signal may be missed entirely. Also, at the high energy range of 2039 keV noise has the effect of degrading our energy resolution. This would not allow us to as finely measure the energy of the 0v2B decay peak and would subsequently lead to more uncertainty in the calculated mass scale of the neutrino. For these reasons, noise monitoring and measurement are key to the operation of the MAJORANA DEMONSTRATOR.
More information on the MAJORANA DEMONSTRATOR can be found on their homepage.