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CRNS Cosmic Ray Neutron Sensing Probe FINAPP

We The CRNS Cosmic Ray Neutron Sensing FINAPP probe is able to count neutrons generated by the interaction between cosmic ray and water present in the soil, in the biomass, in the snow.

The FAO - Food and Agriculture Organization of the United Nations - affirms that the CRNS technology is the best for practising smart agriculture. https://www.iaea.org/sites/default/files/21/09/nuclear-science-and-technology-for-climate-adaptation-and-resilience.pdf

Thanks to CRNS technology, the Cosmic Ray Neutron Sensing FINAPP probe can provide real-time, large scale, in depth measurements of:

  • Average value of soil moisture
  • BWE: biomass water equivalent
  • SWE: snow water equivalent

CRNS FINAPP probe for soil moisture monitoring in large scale, in depth and in real-time

How does the Cosmic Ray Neutron Sensing FINAPP probe work?

Neutrons are naturally moderated by water molecules. The CRNS probe can relate the counting of cosmic neutrons with the water content of the soil, snow and biomass, with different FINAPP model options.

Since the neutron count depends on both the quantity of water present in that area, as well as on the availability of cosmic radiation at that given time, it is important to know the value of total incoming cosmic rays (fast neutrons). This is done by counting a subatomic particle strictly related to the cosmic neutrons: the mouns. FINAPP is the only instrument in the world that is capable of counting the total incoming mouns. Temperature and barometric pressure are also measured, to adjust the measurement to the local environmental conditions. 


The Cosmic Ray Neutron Sensing FINAPP probe has a detector containing Lithium-6. When a neutron hits the lithium molecule, a pulse of light is generated, and energy is released. The photo-multiplier next to the detector transports this light (energy) and amplifies it to the electronic board which is ultimately transforming the signal to electricity and interpreting it. The mouns are indeed electrically charged, therefore these are the particle measured when it comes to count total incoming neutrons (fast neutrons).

The Cosmic Ray Neutron Sensing FINAPP probe can also discriminate and count separately the slow or thermal neutrons (with lower energy), after they hit the water present in the soil.  The difference between the fast neutron incoming from the sky, and the slow neutrons bouncing back from the ground, will give the final count of neutrons related to water content in the soil. A decrease in the neutron counting is related to an increase of water content, and vice versa.

Since fast neutrons penetrate in the ground for many centimeters (meters, in the snow), the data provided is representative in depth, and not only superficially. Similarly, since slow and thermal neutrons are spatially distributed and scattered over large distances in the air, it is possible to monitor the water content over large areas, about 5ha at sea level and under standard conditions, or up to 20ha at high altitudes, as the thinner air allows slow neutrons to travel longer. The data obtained represents the average value of water content over the area covered by the probe.


This Cosmic Ray Neutron Sensing FINAPP probe can also count gamma rays. The gamma radiation count is used in scientific literature for both the estimation of the biomass water equivalent BWE and as a detector of precipitation (rain, snow or hails), since this reduces the value of gamma rays which are "washed away".

CRNS Cosmic Ray Neutron Sensing Probe for soil moisture
CRNS Cosmic Ray Neutron Sensing Probe for soil moisture in hazelnut


FINAPP probe options
FINAPP probe options

FINAPP probe modules
FINAPP probe modules



The probe is already equipped with a datalogger made up of:

  • Custom electronic board
  • Firmware and all necessary software to discriminate neutrons and muons from other particles and noise
  • Atmospheric pressure sensor
  • Internal temperature sensor
  • External temperature sensor - optional
  • External relative humidity sensor - optional
  • Auto diagnostic system

Measured data are saved locally on an SD card. The stored parameters are:

  • Time stamp (UTC)
  • Counting of neutrons - according to models
  • Counting of muons - according to the models
  • Counting of gamma - according to models
  • Atmospheric pressure (hPa)
  • Internal temperature (°C)
  • External temperature (°C) – according to models
  • External humidity (%) – according to models
  • GPS position – according to models
  • Voltage (V)

Finapp deisng
FINAPP design


Possible hardware:            Probe Integration time*
Finapp-3                              6 hours
Finapp-4                              5 hours
Finapp-5                              2 hours

*Soil moisture is updated every hour and is calculated as the rolling average of the last 6h – 5h – 2h depending on probe’s model


Soil moisture (gravimetric or volumetric if soil density is known) averaged (1 value) over a circular area of 5 hectares, up to a depth of 30-50cm in standard conditions.


About 2m above the ground (detector at about 1.8m from the ground)


Up to 100 hectares if these conditions are valid:
1. There is a monoculture
2. Irrigation is the same over the entire extension
3. The texture of the soil within the 5 hectares actually scanned by the probe, is repeated in a similar way even on a larger scale. This does not mean that the soil must have a homogeneous composition (only clay, only sandy etc ..) but that the mix of different soils present within the 5 hectares is repeated approximately in the same way even larger.


1. Via API and/or access to FINAPP cloud
2. Via SDI-12 or RS-232 port

CRNS Cosmic Ray Neutron Sensing Probe for soil moisture
CRNS Cosmic Ray Neutron Sensing Probe for soil moisture


Possible hardware:                      Probe Integration time*
Finapp-3 + Finapp-Monitor          12 hours
Finapp-4 + Finapp-Monitor          10 hours
Finapp-5 + Finapp-Monitor           6  hours

*SWE updates every hour and it is the rolling average of the last 12h – 10h – 6h depending on probe’s model


SWE (mm) averaged (1 value) over a circular area of 20m, with a saturation limit of about 2’000mm. Point scale (radius of about 1m) backup measure with no saturation limit (> 10’000mm).


Finapp-Monitor: about 2m above the snow (consider historical maximum snow height)
Finapp-3: on the ground, then covered by snow fall


1. Via API and/or access to FINAPP cloud
2. Via SDI-12 or RS-232 port

CRNS Cosmic Ray Neutron Sensing Probe for soil moisture
CRNS Cosmic Ray Neutron Sensing Probe for soil moisture

More info on the CRNS Finapp Catalogue


BAROMETRIC PRESSURE It is a physical quantity that expresses the ratio between the weight force of the column of air bearing down on a surface, present at any point in the earth's atmosphere, and the measurement of the area of the surface itself. The measurement unit is following the international system in pascals with a barometer. Finapp probe measures atmospheric pressure to get more accurate neutron and muon counts
BWE - Biomass water Equivalent BWE represents the water present within the biomass as well as hydrogen present in the biomass tissue. It can give an excellent indication of the growth status of a crop. Finapp' probes are the only ones that can provide a representative large-scale, real-time BWE measurement.
Calibration Calibration verifies the precision and reproducibility of measurement instruments, such as sensors and measuring systems. The calibration of each Finapp' probe happens at the headquarters in Padova, Italy.
CLIMATE-SMART AGRICULTURAL PRACTICES Climate-smart agriculture (CSA) is an approach that helps guide actions to transform agri-food systems towards green and climate resilient practices. CSA aims to tackle three main objectives:

  • sustainably increasing agricultural productivity and incomes;
  • adapting and building resilience to climate change;
  • reducing and/or removing greenhouse gas emissions, where possible.

Finapp probes can help meeting this goal, by providing soil moisture data "at field scale"

COSMIC RAYS Cosmic Rays are high-energy particles and atomic nuclei that, moving almost at the speed of light, strike the Earth from all directions. As the name implies, they come from the Cosmos, that is, from the space around us. The vast majority of Cosmic Rays are protons (about 90%). We then have atomic nuclei (i.e., atoms without their electrons) of a variety of elements, from the lightest ones such as helium (about 9%) to the heaviest (about 1%) such as iron and uranium.
CRNPs Cosmic ray neutron sensing probes are cosmic rays and neutrons detection probes.
CRNS Cosmic Ray Neutron Sensing - is an innovative technique for measuring water content using cosmic rays. It bridges the gap between point-scale and satellite, measuring water content on the hectare scale. The scientific community has been validating the CRNS technology since many years, but it is not widespread outside of academia. For Finapp is new way of measuring water, a new scale for new applications. You can use CRNS for precision agriculture, estimate of the water resource, early warning for hydrogeological instability and water leaks pre-localization.
Data Logger: A data logger is a device used to store data. Often, a data logger is a complete (stand-alone) instrument, capable of reading different types of electrical signals and storing the data in internal memory, then making it downloadable by a user. The Finapp' probe has a data logger embedded into the electronic board: this makes it much easier to download data, lowering instrumentation size, power consumption, and cost.
Digital I/O Ports: The digital I/O ports are Input/output ports that sense status, read external sensors such us, temperature, humidity, rain gauges, barometric pressure etc. Finapp datalogger has additional modules that make it compatible with popular communication protocols such as SD-12, LoRa and RS-232.
DRIP IRRIGATION Drip irrigation or trickle irrigation is a type of micro-irrigation system that has the potential to save water and nutrients by allowing water to drip. Drip irrigation involves placing tubing with emitters on the ground alongside the plants. The emitters slowly drip water into the soil at the root zone. This type of irrigation made it very difficult to measure soil moisture with point probes, since a few cm differences in probe placement results in a large variation in soil water content. Thanks to Finapp, you can overcome this problem. The CRNS probes provide a soil moisture value representative of the entire plot, including both the wet part near the plant and the dry part of the inter-row.
DROUGHT Drought arises from inadequate rainfall or snowfall, resulting in water scarcity, parched soil, and crop harm. The beginning and end of droughts are uncertain, while prolonged ones significantly disrupt both water and food supply, sometimes even prompting involuntary migration. The effects of climate change (for example) include sea level rises, and increased frequencies of droughts, storms, and extreme temperatures.
Early Warning Pre-warning is used to predict a hazard situation that will affect a given geographic area, in a given time frame, due to one or more adverse phenomena such as flooding, landslides, fire. Finapp produces a forecast for the risk of landslides, floods, and fires, based on soil moisture data measured by Finapp' probes, past and future weather data, and ad hoc models.
EMERGENCY IRRIGATION Water stress is a temporary or prolonged condition of lack of water, usually lacking at ground level. As all plant stresses, it can result in primary damage or secondary damage to a plant. Irrigation in viticulture is the process of applying extra water in the cultivation of grapevines.
Epithermal neutrons A neutron with low kinetic energy, generated by the interaction between fast neutrons and water molecules present in the soil and snow. Measurable only with heavy and expensive probes. For Finapp, it is the most important particle: it is the messenger that brings the information about the amount of water in the soil or snow, tens of meters away from the probe, precisely because it is able to travel long distances before decaying.
Evapotranspiration (Et0)  The evapotranspiration means the amount of water no longer available in the soil due to evaporation and transpiration. Transpiration is the movement of liquid through a plant and release through the stomata of the plant as water vapor. There are several methods for estimating evapotranspiration, the most common are the Penman Monteith equation and Bowen ratio technique. Using Finapp probes, it is possible to evaluate the result of actual evapotranspiration, i.e., soil moisture loss.
Fast neutron (FN) A neutron with high kinetic energy, part of the particle cascade that forms cosmic radiation. Impossible to measure without very expensive and complex instrumentation. For Finapp is a particle of fundamental importance because it provides the initial reference number to calculate how much water is present around the probes. Fast neutrons can be easily measured thanks to muons: this innovation is part of Finapp' patent.
FINAPP Finapp is an innovative Startup, Spinoff of the University of Padua, which brings innovation to CRNS probes. The name comes from "FIsica Nucleare APPlicata" - the Physics Department of the University of Padua (Italy), where the innovative idea of producing small, lightweight, compact, inexpensive, highly efficient CRNS sensors was born.
RISK Risk, in the field of civil protection, is the product of: Hazard x Vulnerability x Exposed Value: Hazard is the probability that a phenomenon - like flood, land slide, fire - will occur over a certain period of time, in a given area. The vulnerability of an element (people, buildings, infrastructure, economic activities) is the propensity to suffer damage as a result of an adverse event. Exposed value is the value of each of the elements at risk in a given area, such as human lives or settlements. Finapp, by integrating meteorological data and specific modelling with soil moisture data, can provide early warnings for landslides, flooding, and fires, so as to mitigate risk.
FREQUENCY DOMAIN REFLECTOMETRY (FDR) / Time Domain reflectometry (TDR) Frequency domain (FD) sensor is an instrument developed for measuring soil moisture content. The instrument has an oscillating circuit, the sensing part of the sensor has to be in good contact with the soil, and the operating frequency will depend on the value of soil's dielectric constant. Time domain reflectometer (TDR), determine the water content of the soil by measuring the dielectric properties of the soil through the travel time of an electromagnetic pulse through conductors located in the soil. TDR probes are more accurate, although more expensive, and were the standard for measuring soil moisture. The great limitation of this technology is that it is representative only at point scales. Finapp overcomes this limitation by providing representative soil moisture values "at field level".
GAMMA RAY A gamma ray, also known as gamma radiation (symbol γ or γ\gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. Finapp uses its gamma-ray detector to assess BWE - biomass water equivalent - on a large scale and in real time.
GPS (Global Positioning System) A satellite system used to determine geographic position and deviation. Finapp devices can interrogate some GPS receivers then store the GPS position data. Knowing the location is critical for geo referencing the neutron and muon counts that are the basis of Finapp soil moisture maps and the pre-location of water losses along aqueducts.
HIGH ENERGY NEUTRONS Read the description about Fast neutrons
IRRIGATION ADVICE The amount of water needed for irrigation at any moment depends on four factors: soil moisture level, soil type, crop type and its phenological phase, weather forecast. There are many companies that provide irrigation advice, but none have any real knowledge of soil moisture because the FDR/TDR probes provide representative data of a few cm, while the satellite cannot penetrate deep into the soil. Finapp overcomes these limitations with its CRNS probes that measure soil moisture on a large scale, in depth and in real time.
LANDSLIDES Landslides, also known as landslips, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, shallow or deep-seated slope failures, mudflows, and debris flows. Gravity is the primary driving force for a landslide to occur, but there are other factors affecting slope stability that produce specific conditions that make a slope prone to failure. In many cases, specific events can trigger landslides i (such as a heavy rainfall, an earthquake, a slope cut to build a road, and many others), although this is not always identifiable. Landslide mitigation describes the policy and practices for reducing the risk of human impacts of landslides, reducing the risk of natural disaster. For the mitigation of this risk, Finapp provides a fundamental parameter for assessment, which is the soil water saturation index, through the areal measurement of soil moisture.
LoRa The acronym LoRa refers to a long-range telecommunications technology, better known as LoRaWAN (Low Power Wide Area Network). The Finapp probe integrates within it a module for data transmission and reception with LoRa protocol.
LOW ENERGY NEUTRONS Read the description of epithermal neutrons
MUONS An unstable subatomic particle of the same class as an electron (a lepton), but with a mass around 200 times greater. Muons make up much of the cosmic radiation reaching the earth's surface. For Finapp, muons are misunderstood particles, and therefore not considered by the CRNS community. Until the day Finapp realized that it could be used to easily and cheaply calculate how many fast neutrons reach the ground.
Non-invasive and non-contact measures. With non-invasive measurement means an investigation that does not change the object being analysed in any way. Non-contact is an investigation that does not involve physical contact between the object being analysed and the instrument analysing it. Finapp probes, installed 2m above the ground, measure soil moisture without being in contact with it and without altering its structure in any way.
Probe A device used to send back information. Finapp uses CRNS probes to measure the water content on large scale, in depth and in real time.
RAIN GAUGE Rain gauge is a device used for measuring rainfall.
RELATIVE HUMIDITY (RH) Relative humidity (RH) (expressed as a percent) also measures water vapor, but RELATIVE to the temperature of the air. In other words, it is a measure of the actual amount of water vapor in the air compared to the total amount of vapor that can exist in the air at its current temperature.
SALINITY / ELECTRICAL CONDUCTIVITY (EC) Electrical resistivity (also called volume resistivity or specific electrical resistance) is a fundamental specific property of a material that measures its electrical resistance or how strongly it resists electric current. Soil resistivity is a measure of how much the soil resists or conducts electric current. It is a critical factor in design of systems that rely on passing current through the Earth's surface. Electrical conduction in soil is essentially electrolytic and for this reason the soil resistivity depends on moisture content, salt content, temperature (above the freezing point 0 °C)
Because of the variability of soil resistivity, IEC standards require that the seasonal variation in resistivity be accounted for in transmission system design. Soil resistivity can increase by a factor of 10 or more in very cold temperatures.
SDI-12 protocol SDI-12 protocol is the communication protocol for transferring data between battery-powered data recorders and sensors. Sensors can measure one or more parameters, then transmit the data back to the data logger following the SDI-12 protocol. Both the sensor and the data logger must follow the protocol specifications. It means “Serial Data Interface at 1200 baud”. Finapp integrates the SDI-12 protocol within its data logger.
SNOW PILLOW A snow pillow is a device for measuring snowpack, especially for automated reporting stations. The snow pillow measures the water equivalent of the snowpack based on the weight of the overlying snow. It represented the standard for automatic SWE measurements despite various limitations such as not very precise measurements for bridging phenomena, significant sizes and weights, need for perfectly flat terrain, and, most importantly, poor representativeness of the large-scale data. Finapp overcomes all these limitations with CRNS probes that provide large-scale SWE data with a lightweight and compact probe.
Snow water Equivalent (SWE) Measurement of the amount of water contained in snowpack. Result in mm of water.
When the SWE increases, the intensity of natural background neutrons decreases.
SOIL MOISTURE Soil Moisture (SM) is “the total amount of water, including the water vapor, in an unsaturated soil.” Soil moisture —sometimes also called soil water — represents the water in land surfaces that is not in rivers, lakes, or groundwater, but instead resides in the pores of the soil. The level of soil moisture is determined by a host of factors beyond weather conditions, including soil type and associated vegetation. Finapp measures soil moisture on any type of soil, even in the presence of many stones or rocks, because it is sensitive to the presence of water molecules. Why measure soil moisture? Soil moisture plays a key role in the life of the plant. Nutrients in the soil solution provide the plant with the "food" it needs to grow. Water is also essential for regulating plant temperature through the process of transpiration. Plant root systems are better developed when growing in a proper moist soil. Excessive levels of soil moisture, however, can lead to anaerobic conditions that can promote the growth of plant and soil pathogens. Finapp provides the intermediate-scale soil moisture measurements by using cosmic-ray hydro metrology, the ground-based technique that can average over hundreds of meters.
SOIL SATURATION Soil Saturation is the threshold at which all the pores (empty spaces between the solid soil particles) are filled with water. The VWC at this threshold varies from 30 percent in sandy soils to 60 percent in clay soils. It is one of the key parameters for providing proper irrigation advice.
SOIL TEXTURE Soil texture is classified by the fractions of each soil separate (sand, silt, and clay) present in a soil. The twelve classifications are sand, loamy sand, sandy loam, loam, silt loam, silt, sandy clay loam, clay loam, silty clay loam, sandy clay, silty clay, and clay Soil type determines the water-holding capacity and thus the moisture content of the soil. It is an extremely local parameter with great spatial variability: for this reason, you would need dozens of point probes to know soil moisture "at field scale," which Finapp solves with a single CRNS probe capable of providing a representative value on the hectare scale.
SPRINKLER IRRIGATION An irrigation sprinkler is a device used to irrigate (water) agricultural crops, lawns, landscapes, golf courses, and other areas.  Sprinkler irrigation system allows application of water under high pressure with the help of a pump. It releases water similar to rainfall through a small diameter nozzle placed in the pipes. Water distributes through a system of pipes, then into air and irrigates in most of the soil type due to wide range of discharge capacity. We advise to consider  type of irrigation, sprinkler or drip, is one of the parameters considered in our irrigation advice.
Surface soil moisture Surface soil moisture is the water that is in the upper 10 cm of soil, whereas root zone soil moisture is the water that is available to plants—generally considered to be in the upper 200 cm of soil.
Surface soil water content (SWC) Soil water content (WC) refers to the amount of water in the soil, whereas available water content (AWC) refers to the amount of water in the soil profile that can be used by plants
TENSIOMETERS (SOIL MATRIC POTENTIAL SENSORS) Soil matric potential (SMP) is realistic criterion for measuring soil water availability to plants as it constitutes the force with which water is held by soil matrix (soil particles and pore space) and is measured by tensiometer.
Thermal neutron (TN) Thermal neutron, any free neutron (one that is not bound within an atomic nucleus) that has an average energy of motion (kinetic energy) corresponding to the average energy of the particles of the ambient materials. Relatively slow and of low energy, thermal neutrons exhibit properties, such as large cross sections in fission, which make them desirable in certain chain-reaction applications. Furthermore, the long de Broglie wavelengths of thermal neutrons make them valuable for certain applications of neutron optics. Thermal neutrons are produced by slowing down more energetic neutrons in a substance called a moderator after they have been ejected from atomic nuclei during nuclear reactions such as fission.
TIME DOMAIN TRANSMISSOMETRY (TDT) The term time domain transmissometer (TDT) describes time measurement methods used to characterize the quality of signal transmissions. In time domain transmissometer, the time required for an electromagnetic wave to propagate along a given length of the transmission line is measured. TDT measures the time from the start to the end of the loop for the propagation of an electrical pulse. Similar to TDR, a pulse measured via TDT will be slower in wetter soils than drier soils. The velocity of the pulse is related to the dielectric constant
TOTAL DISSOLVED SOLIDS (TDS) Total Dissolved Solids (TDS) are all the good and bad elements in your drinking water. These can be organic and inorganic substances such as minerals, salts, metals, cations, or anions dissolved in water. The TDS level is measured in parts per million (PPM) and milligrams per Liter (mg/L)
Volumetric water Content (VWC) The volumetric water content is the ratio of the volume of water to the unit volume of soil. Volumetric water content can be expressed as ratio, percentage or depth of water per depth of soil (assuming a unit surface area), such as inches of water per foot of soil. Finapp probe returns volumetric soil moisture if the bulk density is known.
Water potential Water potential is the force with which water is retained by the soil and, therefore, the work that must be carried out to remove it from it.
Weather Forecast Weather forecast are the application of knowledge of atmospheric science and technology to predict the state of the atmosphere (weather) at a future time and at a specific place.  Numerical forecasting models can calculate weather prediction, which are mathematical models of the Earth's atmosphere that use current weather conditions (atmospheric state) as input or initialization and the fundamental equations of the model itself for weather prediction at later times (prognosis). Finapp integrates weather forecasts to predict future soil moisture conditions, to provide early-warning for the risk of landslides, floods, fires, and to provide irrigation advice in agriculture.
Weather Station An application-specific data acquisition system that monitors meteorological conditions. Finapp stations could eventually include a limited quantity of meteorological sensors (for example, rain gauge, temperature and RH probe, punctual soil moisture probe, wind vane, anemometer, and pyranometer).
WILDFOREST FIRE Wildfire, forest fire, bushfire, wildland fire or rural fire is an unplanned, uncontrolled and unpredictable fire in an area of combustible vegetation. The fire danger indicators are components of the Canadian Forest Fire Weather Index (FWI) System. Finapp, with large-scale, in-depth, real-time knowledge of soil moisture, is able to provide more accurate fire risk.
WILTING POINT Water content in a soil when most cultivated plants can no longer extract water from it.  It is one of the key parameters for providing proper irrigation advice.
CRNS Cosmic Ray Neutron Sensing Probe for soil moisture