Showing posts with label Alice. Show all posts
Showing posts with label Alice. Show all posts

Friday, November 21, 2014

CERN Open Data Portal: LHC experiments open to the Public

The web-based CMS event display, accessible through the CERN Open Data Portal, shows a proton-collision event recorded by the CMS detector. 

Credit: CMS /Open Data Portal

CERN today launched its Open Data Portal where data from real collision events, produced by experiments at the Large Hadron Collider (LHC) will for the first time be made openly available to all.

It is expected that these data will be of high value for the research community, and also be used for education purposes.

"Launching the CERN Open Data Portal is an important step for our Organization. Data from the LHC programme are among the most precious assets of the LHC experiments, that today we start sharing openly with the world."

"We hope these open data will support and inspire the global research community, including students and citizen scientists," says CERN Director-General Rolf Heuer.

The principle of openness is enshrined in CERN's founding Convention, and all LHC publications have been published Open Access, free for all to read and re-use.

Widening the scope, the LHC collaborations recently approved Open Data policies and will release collision data over the coming years.

The first high-level and analysable collision data openly released come from the CMS experiment and were originally collected in 2010 during the first LHC run.

This data set is now publicly available on the CERN Open Data Portal. Open source software to read and analyse the data is also available, together with the corresponding documentation.

The CMS collaboration is committed to releasing its data three years after collection, after they have been thoroughly studied by the collaboration.

"This is all new and we are curious to see how the data will be re-used," says CMS data preservation coordinator Kati Lassila-Perini.

"We've prepared tools and examples of different levels of complexity from simplified analysis to ready-to-use online applications. We hope these examples will stimulate the creativity of external users."

In parallel, the CERN Open Data Portal gives access to additional event data sets from the ALICE, ATLAS, CMS and LHCb collaborations, which have been specifically prepared for educational purposes, such as the international masterclasses in particle physics benefiting over ten thousand high-school students every year. These resources are accompanied by visualisation tools.

"Our own data policy foresees data preservation and its sharing. We have seen that students are fascinated by being able to analyse LHC data in the past and so, we are very happy to take the first steps and make available some selected data for education" says Silvia Amerio, data preservation coordinator of the LHCb experiment.

"The development of this Open Data Portal represents a first milestone in our mission to serve our users in preserving and sharing their research materials. It will ensure that the data and tools can be accessed and used, now and in the future," says Tim Smith of the CERN IT Department.

All data on OpenData.cern.ch are shared under a Creative Commons CC0 public domain dedication; data and software are assigned unique DOI identifiers to make them citable in scientific articles; and software is released under open source licenses.

The CERN Open Data Portal is built on the open-source Invenio Digital Library software, which powers other CERN Open Science tools and initiatives.

Friday, September 26, 2014

New Horizons has One Last Sleep til Pluto

On Aug. 25, New Horizons crossed the orbit of Neptune-the last planetary orbit crossing during cruise.

Now the spacecraft is outbound for Pluto.

On Aug. 29 the team put New Horizons into hibernation for the final time, prior to its encounter with Pluto.

This last hibernation lasts 99 days and ends on Dec. 6.

After seven-plus years of hibernating through most of the 2.5-billion mile journey from Jupiter to Pluto and the inner reaches of the Kuiper Belt, the spacecraft has reached the final, short leg of cruise.

New Horizons will be re-awakened for the last time in just 10 weeks. Once this has been done, 'encounter' preparations will begin, and six weeks later, the Pluto encounter itself will begin.

At that time, the New Horizons team will have good cause to celebrate. They will have reached the outer end of our Solar System, twenty-five years after first wondering if Pluto might someday be explored.

This summer's eighth and final "pre-Pluto" spacecraft and payload Active Check Out (ACO-8) lasted from June through late August. All spacecraft subsystems-both prime and backup-were checked out and were found to be operating successfully.

Additionally, the team performed their first course-correction since 2010, uploaded the final autonomy system software for the encounter, checked out all seven payload instruments, conducted some final instrument calibrations, and performed their first optical navigation campaign to home in on Pluto using New Horizons' Long Range Reconnaissance Imager (LORRI).

Those activities went well, and so did many others, including more sampling of the heliospheric plasma and dust environment with PEPSSI, SWAP and Student Dust Counter instruments.

The only real anomaly of the entire ACO-8 was a failed startup of a single Alice ultraviolet spectrometer observation.

That observation was to study the distribution of interplanetary hydrogen near Neptune's orbit; it failed because Alice was much colder than was planned, and onboard software "safed" (or turned off) Alice's high-voltage power supply when it took too long to get to its set point voltages.

The team have now learned that they need to adjust some timing settings for future power-ons when Alice will be as cold or even colder, On its approach to Pluto.

Additionally, ACO-8 was the subject of a recent news story from New Horizons: While testing the methods to be used to search for hazards in the Pluto system on approach, the spacecraft detected Pluto's little moon Hydra.

The team didn't think it would be possible to see Hydra until early in 2015, when the spacecraft was much closer, but science team members John Spencer and Hal Weaver found Hydra in the July hazard-sequence test.

The New Horizons team sees the early detection of Hydra as good news, because it anticipates their ability to detect currently unknown moons and rings close to Pluto.

Tuesday, September 16, 2014

New Horizons: Awaiting New Results on Pluto's Atmosphere

Artist's impression of Pluto, with its wispy atmosphere.

Data from New Horizons' Alice ultraviolet spectrograph will answer a full range of questions about the composition and structure of that atmosphere.

What is Pluto's atmosphere like? It seems like I've been wondering about that for decades!

We've known so little for so long about Pluto's atmosphere, other than it's low-pressure, made mostly of molecular nitrogen (with a little methane and carbon monoxide mixed in) and may be quite extended, it's nice to realise that we'll know a whole lot more after New Horizons visits in summer 2015.

Alice UV spectrograph
My professional interests on New Horizons lie with Pluto's upper atmosphere, what it's made of, how it interacts with space, and how it is processed by sunlight into different gases and aerosols.

A problem in planning atmospheric observations for New Horizons during the flyby is that we really don't know what to expect.

Only a few models have been made that try to predict the composition of Pluto's atmosphere, and they don't agree very much with each other because of the many present uncertainties.

So our plans generally include a lot of survey-type observations, where we try not to assume too much about what we will detect, but are ready for anything.

The best example of this is the Pluto solar occultation observation.

Just Joking!
The Alice ultraviolet spectrograph will watch the Sun set (and then rise again) as New Horizons flies through Pluto's shadow, about an hour after closest approach.

Watching how the different colours of sunlight fade (and then return) as New Horizons enters (and leaves) the shadow will tell us nearly all we could ask for about composition (all gases have unique absorption signatures at the ultraviolet wavelengths covered by Alice) and structure (how those the absorption features vary with altitude will tell us about temperatures, escape rates and possibly about dynamics and clouds).

When the New Horizons data start coming down, these are the data I'll be waiting for the most!

Saturday, January 25, 2014

ESA Rosetta: NASA instruments on comet spacecraft begin activation countdown

This artist's impression shows the Rosetta orbiter at comet 67P/Churyumov-Gerasimenko. 

Credit: ESA /ATG Medialab

Three NASA science instruments are being prepared for check-out operations aboard the European Space Agency's Rosetta spacecraft, which is set to become the first to orbit a comet and land a probe on its nucleus in November.

Rosetta was reactivated Jan. 20 after a record 957 days in hibernation. U.S. mission managers are scheduled to activate their instruments on the spacecraft in early March and begin science operations with them in August.

The instruments are an ultraviolet imaging spectrograph, a microwave thermometer and a plasma analyzer.

Claudia Alexander
"U.S. scientists are delighted the Rosetta mission gives us a chance to examine a comet in a way we've never seen one before—in orbit around it and as it kicks up in activity," said Claudia Alexander, Rosetta's U.S. project scientist at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

"The NASA suite of instruments will provide puzzle pieces the Rosetta science team as a whole will put together with the other pieces to paint a portrait of how a comet works and what it's made of."

Rosetta's objective is to observe the comet 67P/Churyumov-Gerasimenko up close. By examining the full composition of the comet's nucleus, and the ways in which a comet changes, Rosetta will help scientists learn more about the origin and evolution of our solar system and the role comets may have played in seeding Earth with water, and perhaps even life.

The ultraviolet imaging spectrograph, called Alice, will analyze gases in the tail of the comet, as well as the coma, the fuzzy envelope around the nucleus of the comet.

The coma develops as a comet approaches the Sun.

Alice also will measure the rate at which the comet produces water, carbon monoxide and carbon dioxide.

These measurements will provide valuable information about the surface composition of the nucleus.

The instrument also will measure the amount of argon present, an important clue about the temperature of the solar system at the time the comet's nucleus originally formed more than 4.6 billion years ago.

The Microwave Instrument for Rosetta Orbiter (MIRO)will identify chemicals on or near the comet's surface and measure the temperature of the chemicals and the dust and ice jetting out from the comet.

The instrument also will see the gaseous activity in the tail through coma.

The Ion and Electron Sensor is part of a suite of five instruments to analyze the plasma environment of the comet, particularly the coma.

The instrument will measure the charged particles in the Sun's outer atmosphere, or solar wind, as they interact with the gas flowing out from the comet while Rosetta is drawing nearer to the comet's nucleus.

Read the full article here