Press Release September 2024

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Ultrafast digitizers used to identify neutrinos
in huge international project
ADC cards by Spectrum Instrumentation used for largest liquid-neutrino-detector of mankind
Leading scientific research
Grosshansdorf, Germany – 04.09.2024. Until recently, neutrino particles were thought to have no mass but now the theoryis that they actually have mass with a very tiny value as well as coming in three different ‘flavours’ which they can switch
back and forth. Often called ghost particles, studying them is very difficult as they typically pass through most normal matter
unimpeded and undetected, so specialist detectors have to be built to hunt for them. The latest one is called JUNO, located750m below ground in Jiangmen, China, and it is made possible by 17 different countries with 730 scientists working in 74
Universities and national laboratories, that have joined forces on this 400-million-euro project. To develop the core part ofthe detector, the liquid scintillator, ultrafast digitizer cards by Spectrum Instrumentation are used.
JUNO is precisely positioned betweeneight existing nuclear reactors thatprovide a source of neutrinos for study.
At its heart is a gigantic, highlytransparent, acrylic sphere with an innerdiameter of 34.5 m, filled with 20,000
tons of a specially developed oil-like
substance. This liquid scintillator createsphotons when a neutrino interacts withit, and it is encased in a large 35,000 tons
water pool. The photons are detected byan array of ca. 45,000 photo multipliertubes (PMTs) that surround the sphere.
The teams at the Technical University ofMunich (TUM) and at the Johannes
Gutenberg University in Mainz are using
M4i.2212 digitizer cards by Spectrum
Instrumentation in their high-precision,lab-scale experiments to characterize theThe JUNO main detector 750m underground in a dedicated laboratory. The photo shows the (stillliquid scintillators, which requireempty) water pool of the detector with the central scaffolding. Inside this globe, the acrylic sphereadvanced data acquisition. When thewith 34.5m diameter is placed, filled with the liquid scintillator. The white cover just protects
JUNO detector is commissioned at thesensitive components during mounting.
end of 2024, it will be the largest, liquid
neutrino detector built by mankind. The detector will drastically enhance our knowledge about interactions and properties ofthese elusive ghost particles.
Neutrino detection
The central acrylic sphere contains the liquid scintillator surrounded by a layer of water. Both have to be ultra-pure as thesmallest amount of contamination could contain a radioactive material. During construction, workers had to wear two pairs ofgloves as even the sweat from a fingerprint could contaminate and ruin the entire project. The detector sits in a specially dug
space that is 750 m below ground to shield it from ambient radiation.
When a neutrino interacts with the liquid scintillator (LS), it deposits the energy of the interaction with the molecules of thissubstance. The enormous light output of the LS (typically > 10.000 Photons / MeV) ensures a precise determination of thedeposited energy. It would be highly beneficial if the direction of the incident neutrino could also be reconstructed. Here, thefaint but directional Cherenkov light from neutrino’s initial passage through the water is paired to give physicists this information.

Headquarters

US OfficeSpectrum Instrumentation GmbH, Germany
Phone: +49 4102-6956-0
Email: Info@spec.de

Spectrum Instrumentation Corp., USA
Phone: (201) 562-1999
Email: Sales@spectrum-instrumentation.com

https://www.spectrum-instrumentation.com

Press Release September 2024

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The aim of the current development of liquid scintillators in
Munich and Mainz is to separate the fast but faint Cherenkov
light from the dominant scintillation light in order to enable
simultaneous energy and directional reconstruction. Therefore,
the team under Dr. Hans Steiger constructed several, precision,table-top experiments with enhanced light-collection
capabilities and time-resolution.
“We chose the digitizer cards from Spectrum as they provide us
with state-of-the-art performance but, unlike rival offerings,
Typical light emission kinematics for a slow liquid scintillation mixtur.
they are not expensive or custom creations,” said Dr. Hans
The Cherenkov light (red line) in form of a sharp peak in time isfollowed by the slower scintillation light decay (green line)
Steiger, who is leading the project. “Spectrum’s modular
approach means that we could specify exactly what we needed
the cards to do so we were not having any compromises or
wasting money on unwanted features. I love the fact that they are a standard PCIe product so that we can expand the systemon a standard computer chassis as we received more funds. As a university taking part in major long-term international projects,
we need to have reliable parts and Spectrum’s five-year warranty gives us piece of mind.”
JUNO results also push astronomy research
Beyond the work on event reconstruction, the team contribute a calibration project to JUNO. This characterizes the detectormaterial using radioactive gamma and neutron sources where the energy and incident direction are pre-determined. “Ourcharacterizations of the liquid scintillators are only possible because of the ultrafast digitizer cards that enable us to work with
timeframes that are measured in picoseconds. Also, the dynamic range of 5V is much better than rivals that are typically 1V
which means they can easily manage the 3V pulses in our PMTs that we encounter,” Meishu Lu, a PhD student in the TUM group
pointed out. And Manuel Böhles working in Mainz added, “Spectrum has been really supportive in helping us working out thebest solutions for our project and helping resolve any issues that we encounter with a phone call directly with one of theirengineers. It’s great that they are committed to supporting fundamental research in many universities such as ours.”
The diagram shows the first pulse from the Cherenkov radiation followed by thescintillation signal that gives the energy information. This happens in less than twonanoseconds. By combining this information, the type of particle can be determined
and where it came from. This could be from one of the Chinese reactors, the sun,the heart of the earth or deep space. “We have never been able to know exactly
where a neutrino was coming from in scintillation detectors before, so this opens up
whole new areas of research,” explained Dr. Steiger. “If, for example, a dying star, or
so-called supernova, emits large amounts of neutrinos in the sky, we are now able
not only to see the neutrinos but also reconstruct with high precision, the point inthe sky, where this explosion took place. Effectively we now have a telescope to look
into these different neutrino sources to better understand the processes. By
detecting light over the entire spectrum, gravitational waves and now also neutrinos
with high statistics, energy resolution and directionality start a new era of multimessenger astronomy.”

The M4i.2212-x8 PCIe digitizer by Spectrum
Instrumentation with 1.25 GS/s sampling
speed on 4 channels.

About Spectrum Instrumentation
Spectrum Instrumentation, founded in 1989, uses a unique modular concept to design and produce a wide range of more than
200 digitizers and generator products as PC-cards (PCIe and PXIe) and stand-alone Ethernet units (LXI). In over 30 years, Spectrum
has gained customers all around the world, including many A-brand industry-leaders and practically all prestigious universities.
The company is headquartered near Hamburg, Germany, known for its 5-year warranty and outstanding support that comes
directly from the design engineers. More information about Spectrum can be found at www.spectrum-instrumentation.com

Headquarters

US OfficeSpectrum Instrumentation GmbH, Germany
Phone: +49 4102-6956-0
Email: Info@spec.de

Spectrum Instrumentation Corp., USA
Phone: (201) 562-1999
Email: Sales@spectrum-instrumentation.com

https://www.spectrum-instrumentation.com