Majorana Information and Resources

The ultimate objective of the Majorana Collaboration is to study neutrinoless double beta decay (0νββ) with an effective Majorana-neutrino mass sensitivity below 50 meV to characterize the Majorana nature of the neutrino, the neutrino mass spectrum, and the absolute mass scale. An experimental study of the neutrino mass scale implied by neutrino oscillation results is now technically within our grasp. This exciting physics goal is best pursued using the well-established technique of searching for 0νββ of ⁷⁶Ge, augmented with recent advances in signal processing and detector design.

The NuSAG report suggests a first, intermediate step of <180 kg of active mass. This intermediate Majorana experiment will consist of ~100 kg of ⁷⁶Ge in the form of high-resolution intrinsic germanium detectors located deep underground within a low-background shielding environment. Observation of a sharp peak at the ββ endpoint will quantify the 0νββ half-life and thus the effective Majorana mass of the electron neutrino.

Please see the overview talk or recent white paper for more details.

Newsroom

Memorial for Dr. Ron Brodzinski.
New detector technology under development which may benefit Majorana! (Hull et al, 28th Seismic Research Review: Ground-Based Nuclear Explosion Monitoring Technologies, 2006, also PNNL-SA-52058)
Preprint: New detector design for dark matter may be revolutionary for Majorana!
NuSAG report is out!
Recommendation: The Neutrino Scientific Assessment Group recommends that the highest priority for the first phase of a neutrino-less double beta decay program is to support research in two or more neutrino-less double beta decay experiments to explore the region of degenerate neutrino masses (νββ > 100 meV). The knowledge gained and the technology developed in the first phase should then be used in a second phase to extend the exploration into the inverted hierarchy region of neutrino masses (νββ > 10-20 meV) with a single experiment.
APS Multi-divisional Neutrino Science Review is out!
Recommendation 1: "We recommend, as a high priority, a phased program of sensitive searches for neutrinoless nuclear double beta decay. In this rare process, one atomic nucleus turns into another by emitting two electrons. Searching for it is very challenging, but the question of whether the neutrino is its own antiparticle can only be addressed via this technique. The answer to this question is of central importance, not only to our understanding of neutrinos, but also to our understanding of the origin of mass."

Design Concepts

The Majorana Experiment is a complete next-generation double-beta decay experiment, using a large quantity of enriched materials, state-of-the-art detector fabrication, deep underground facilities, cutting-edge instrumentation and data analyses, and acquisition of complete systems-status data. Construction and operation will be done in extremely clean facilities, and all materials will undergo extensive radiological and mass-spectrometry screening.

Design Galleries

Majorana Publications and Preprints

The proposed Majorana ⁷⁶Ge double-beta decay experiment, (Nuclear Phys B, Proc. Suppl. 138, 217, 2005)
The Majorana Neutrinoless Double-Beta Decay Experiment, (Physics of Atomic Nuclei, 67, No. 11, 2002, 2004)

Select Majorana Technical Documents

The Chemistry of Ultrapure Materials, presented at the Royal Society of Chemistry Environmental Radiochemical Analysis 10th International Symposium, Oxford, UK, 13 - 15 September 2006
Cleaning and Passivation of Cu Surfaces, (E.W. Hoppe, et al., presented at SORMA 06, submitted to NIM)
Electrodeposition Sample Prep, (E.W. Hoppe, et al., presented at MARC VII, Kona, Hawaii April 2006, accepted for publication in JRNC)
Cu Surface Cleaning, (E.W. Hoppe, et al., presented at MARC VII, Kona, Hawaii April 2006, accepted for publication in JRNC)
An Improved Cooled FET Assembly for Ultra-Low-Background Germanium Spectrometers, (Craig Aalseth, Proceedings for IEEE NSS-MIC, 2004)
A simulation method for germanium pulse shapes, (Craig Aalseth, Proceedings for IEEE NSS-MIC, 1999)
White Paper on the Majorana Zero-Neutrino Double-Beta Decay Experiment, (nucl-ex/0311013, 2003)