science

Neutrino Ettore Majorana Observatory

Neutrino Ettore Majorana Observatory is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Neutrino Ettore Majorana Observatory rather than just read about it. In short: The Neutrino Ettore Majorana Observatory (NEMO experiment) is an international collaboration of scientists searching for neutrinoless double beta decay (0νββ). The collaboration has been active since 1989.

Key takeaways

Neutrino Ettore Majorana Observatory belongs to science; place it in that map before memorising details.
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Reproduce the core statement of Neutrino Ettore Majorana Observatory from memory before moving on to harder problems.

Reference excerpt

The Neutrino Ettore Majorana Observatory (NEMO experiment) is an international collaboration of scientists searching for neutrinoless double beta decay (0νββ). The collaboration has been active since 1989. Observation of 0νββ would indicate neutrinos are Majorana particles and could be used to measure the neutrino mass. It is located in the Modane Underground Laboratory (LSM) in the Fréjus Road Tunnel. The experiment has (as of 2018) had 3 detectors, NEMO-1, NEMO-2, NEMO-3 (and a demonstrator module of SuperNEMO-detector) and is planning (as of 2018) to construct a new detector SuperNEMO. The NEMO-1 and NEMO-2 prototype detectors were used until 1997. Latest experiment NEMO-3 was under design and construction from 1994 onwards, took data from January 2003 to January 2011 and the final data analysis was published in 2018. The NEMO-2 and NEMO-3 detectors produced measurements for double neutrino decays and limits for neutrinoless double-beta decay for a number of elements, such as molybdenum-100 and selenium-82. These double beta decay times are important contributions to understanding the nucleus and are needed inputs for neutrinoless decay studies, which constrain neutrino mass. The NEMO collaboration remains active and is constructing an improved SuperNEMO detector. Planning of SuperNEMO and commissioning of SuperNEMO demonstrator module is on-going as of 2019.

Experiment Other 0νββ experiments use the same material for the source of double beta decays and the detector. This allows a large mass of source material to be used and thereby maximizes the sensitivity of the experiment, but limits its flexibility. NEMO takes a different approach, using thin foils of source material surrounded by a separate tracking calorimeter. This allows the use of any source material which can be formed into a thin foil. Also, because its tracking is more accurate, it can reliably detect if two electrons come from the same place, thereby reducing false detections of double beta decays. The experiment has a cylindrical shape with 20 sectors that contain different isotopes in the form of thin foils with a total surface of about 20 m2. The main isotopes used for the neutrinoless double beta decay search are about 7 kg of enriched molybdenum-100 and about 1 kg of selenium-82. The experiment also contains smaller amounts of cadmium-116, neodymium-150, zirconium-96 and calcium-48 foils. Tellurium and copper foils are used for background measurements. A tracking detector on each side of the foil detects electrons and positrons from the double beta decay. They are identified by their curvature in a magnetic field and particle energy is measured in a calorimeter. In 0νββ, the sum of the electron and positron energies will be the(Q value) released in double beta decay. For standard double beta decay the neutrinos, which cannot be observed directly, reduce the detected energy.

Results Neutrinoless double beta decay (0νββ) has not been observed in 5 years of data taking and limits have been set for several isotopes. NEMO-2 reported 0νββ limits for Majoron models of 100Mo, 116Cd, 82Se and 96Zr. NEMO-3 reported precision 2νββ half-lives for its 7 isotopes and 0νββ limits for 96Zr, 48Ca, 150Nd at Neutrino08. NEMO-3 reported 2νββ and more 0νββ limits at SUSY08. In 2014, NEMO-3 reported a 47 kg⋅y search for 0νββ of molybdenum-100 yielded T1/2 > 1.1×1024 years. This can be translated into an upper limit on the effective neutrino mass: mv < 0.3–0.9 eV, depending on the nuclear model. NEMO 2νββ Half-life Measurements

NEMO Highest 0νββ Decay Lower Limits

The 96Zr decay is particularly relevant because of its high Q and use in searches for time-dependence of the physical constants. Geochemical measurements of ZrSiO4 allow comparison of its historic and present rates, by extracting the resultant 96Mo. The final results of NEMO-3 were published in 2018.

SuperNEMO A next generation experiment, SuperNEMO, is under construction. It is based on technology used by the NEMO-3 experiment, but will be more than a factor of ten bigger. The SuperNEMO detector will consist of 20 modules each containing approximately 5 kg of enriched double beta decay emitting isotope in the form of a thin foil. The installation of a first module (using selenium-82) in the LSM is under way, with data taking expected in the second half of 2015. As of 2019, the commissioning of the SuperNEMO demonstration module (basically one of the 20 modulus of the whole SuperNEMO) is underway, and the collaboration continues to plan to construct the whole 20-module SuperNEMO detector.

References

External links NEMO Experiment's official Site Archived 2020-05-29 at the Wayback Machine

Worked examples

Example 1 — a first encounter with Neutrino Ettore Majorana Observatory

Start with the simplest possible case. Write down what Neutrino Ettore Majorana Observatory claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Neutrino Ettore Majorana Observatory before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Neutrino Ettore Majorana Observatory ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Neutrino Ettore Majorana Observatory

In research: Neutrino Ettore Majorana Observatory appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Neutrino Ettore Majorana Observatory in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Neutrino Ettore Majorana Observatory is common in secondary-school and first-year university syllabi. It links to neighbouring topics Neutrino observatories, so understanding it makes those chapters shorter.
In everyday life: Look for Neutrino Ettore Majorana Observatory outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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Frequently asked questions

What is Neutrino Ettore Majorana Observatory in simple terms?

Why does Neutrino Ettore Majorana Observatory matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Neutrino Ettore Majorana Observatory?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Neutrino Ettore Majorana Observatory.