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Black Tea «TOP-RATED»

The Comprehensive Guide to Black Tea: Origins, Science, and Culture

Black tea is one of the most widely consumed beverages in the world, second only to water. Known for its bold flavor and deep amber color, it accounts for more than 78% of global tea consumption. While all "true" teas originate from the same plant—Camellia sinensis—it is the unique processing and full oxidation that gives black tea its signature strength and complexity. 1. From Leaf to Cup: The Production Process

Unlike green tea, which is steamed or pan-fired to prevent oxidation, black tea is allowed to fully oxidize. This transformation involves four key stages:

Withering: Freshly plucked leaves are spread out to lose moisture, making them pliable for rolling.

Rolling: The withered leaves are bruised or crushed to break cell walls, releasing enzymes that initiate the oxidation process.

Oxidation (Fermentation): Leaves are exposed to air in a temperature-controlled environment. During this stage, catechins convert into theaflavins and thearubigins, which create the tea's dark color and robust taste.

Drying: The final step applies heat to stop oxidation and lock in the flavor profile. 2. Popular Varieties and Flavor Profiles

Black tea flavors vary significantly based on terroir, leaf variety (assamica vs. sinensis), and processing.

Black tea is the most oxidized of all "true" teas, known for its bold flavor, dark amber infusion, and significant health profile . While all true teas come from the Camellia sinensis

plant, black tea’s unique character is defined by a complete oxidation process that transforms its chemical structure and color. Harney & Sons Fine Teas The Core Features of Black Tea Description

Fully oxidized, which darkens the leaves and creates deep, robust flavors. Flavor Profile

Ranges from malty and earthy to fruity, floral, or even smoky.

Higher than green or white tea (approx. 40–70 mg per 8oz cup), providing a sustained energy boost. Appearance

Leaves are dark brown or black; the brewed liquor is typically rich amber to burgundy. Processing: From Leaf to Brew

The distinct characteristics of black tea are achieved through a four-step traditional method: What is black tea? All you need to know. - Newby Teas

6. Health Benefits

Black tea is rich in theaflavins and thearubigins (antioxidants formed during oxidation). Research suggests:

Note: High tannins can inhibit iron absorption. If iron-deficient, wait 1+ hour after meals to drink.

5. Yunnan Black Tea (Dian Hong)

Contemporary Trends

Recent trends reshape black tea’s role in global consumption:

Conclusion Black tea is more than a beverage: it is a product of intricate agricultural processes, a driver of historical trade and colonial economies, and a living element of countless cultural rituals worldwide. Its flavor diversity, adaptability to various preparations, and substantial global market ensure that black tea will remain central to social life and economic activity, even as producers and consumers confront environmental and social challenges that require innovation and responsibility.

The Rich History and Benefits of Black Tea

Black tea, one of the most widely consumed types of tea globally, has a rich history dating back to the 17th century. Originating in China, black tea has become an integral part of various cultures, particularly in the UK, India, and Sri Lanka. The unique processing method, which involves withering, rolling, oxidation, and firing, sets black tea apart from other types of tea, such as green, white, and oolong.

History of Black Tea

The history of black tea dates back to the 1600s, during the Ming dynasty in China. Before this period, tea was only consumed in its green form, which was primarily produced in China. However, with the rise of European trade, the demand for a more robust and durable tea increased. Chinese tea producers experimented with different processing methods, leading to the creation of black tea.

The production of black tea involves four main steps:

  1. Withering: Freshly harvested tea leaves are spread out to allow excess moisture to evaporate.
  2. Rolling: The withered tea leaves are rolled to release the enzymes that cause oxidation.
  3. Oxidation: The rolled tea leaves are left to oxidize for a period of time, which turns the leaves dark brown to black in color.
  4. Firing: The oxidized tea leaves are heated to stop the oxidation process, resulting in a dry and stable product.

Types of Black Tea

Black tea comes in a variety of flavors and styles, depending on the region in which it is produced. Some of the most popular types of black tea include: black tea

  1. Assam Tea: Produced in the Assam region of India, Assam tea is known for its strong, malty flavor and rich, full-bodied taste.
  2. Darjeeling Tea: Grown in the Himalayan foothills of India, Darjeeling tea is famous for its light, floral flavor and hint of sweetness.
  3. Ceylon Tea: Produced in Sri Lanka, Ceylon tea is known for its balanced flavor and hint of spice.
  4. Keemun Tea: Originating from China, Keemun tea is known for its smooth, fruity flavor and floral aroma.
  5. Lapsang Souchong Tea: Smoked over pinewood fires, Lapsang Souchong tea has a distinctive smoky flavor.

Health Benefits of Black Tea

Black tea has been associated with numerous health benefits, including:

  1. Antioxidants: Black tea contains a high amount of antioxidants, which help protect the body against free radicals and oxidative stress.
  2. Cardiovascular Health: Regular consumption of black tea has been shown to lower cholesterol levels and reduce the risk of heart disease.
  3. Anti-Inflammatory Properties: Black tea contains polyphenols, which have anti-inflammatory properties and may help reduce the risk of certain cancers.
  4. Improved Cognitive Function: The caffeine and L-theanine in black tea may help improve focus, concentration, and memory.
  5. Digestive Health: Black tea has been shown to have prebiotic properties, which may help support gut health.

Preparation and Serving Suggestions

Black tea can be enjoyed in various ways, depending on personal preference. Here are some popular ways to prepare and serve black tea:

  1. Traditional English Breakfast: Brew strong black tea with milk and sugar for a classic breakfast tea.
  2. Afternoon Tea: Serve black tea with milk, sugar, and a selection of finger sandwiches, scones, and pastries.
  3. Iced Tea: Brew strong black tea and serve over ice with lemon or fruit infusions.
  4. Tea Latte: Mix black tea with steamed milk and a sweetener, such as honey or sugar.

Conclusion

Black tea, with its rich history, diverse flavor profiles, and potential health benefits, is a popular beverage enjoyed worldwide. Whether you prefer a strong and malty Assam tea or a light and floral Darjeeling tea, there's a black tea to suit every taste and preference. Experiment with different brewing methods, flavor combinations, and serving suggestions to discover the perfect cup of black tea for you.

The Rich History and Benefits of Black Tea

Black tea, one of the most widely consumed types of tea globally, has a rich history dating back to the 16th century. Originating in China, black tea has become a staple in many cultures around the world, particularly in the UK, India, and Sri Lanka. This type of tea is known for its distinct flavor profile, which is achieved through a unique processing method that involves fermentation. In this article, we will explore the history of black tea, its production process, and its numerous health benefits.

History of Black Tea

Black tea has its roots in China during the Ming dynasty (1368-1644). It was initially called "red tea" due to the reddish-brown color of the leaves. However, as trade and cultural exchange increased, black tea spread to other parts of Asia, including India and Sri Lanka. The British, who were major tea consumers, played a significant role in popularizing black tea in the 18th century. They established tea plantations in India and Sri Lanka, which became major producers of black tea.

The production of black tea involves several steps, including withering, rolling, oxidation, and firing. The leaves are first withered to remove excess moisture, then rolled to release the enzymes that cause oxidation. This process, which can take several hours, gives black tea its characteristic flavor and color. Finally, the leaves are fired in hot ovens to stop the oxidation process and preserve the tea.

Production Process

The production process of black tea is what sets it apart from other types of tea, such as green tea and white tea. While green tea is steamed or pan-fried to prevent oxidation, black tea is allowed to oxidize, which changes the flavor and color of the leaves. The level of oxidation can vary depending on the manufacturer, but most black teas are oxidized for several hours to achieve the desired flavor profile.

There are several types of black tea, including:

Health Benefits

Black tea has numerous health benefits, making it a popular choice among tea enthusiasts. Some of the key benefits include:

Caffeine Content

Black tea contains a moderate amount of caffeine, which can vary depending on the brand and brewing method. On average, an 8 oz cup of black tea contains around 40-70 mg of caffeine. This is less than coffee, but more than green tea. The caffeine content in black tea can provide a gentle energy boost and improve mental alertness.

How to Brew Black Tea

Brewing black tea is a straightforward process that requires some basic equipment and attention to detail. Here are some tips:

Conclusion

Black tea is a rich and complex type of tea with a long history and numerous health benefits. From its origins in China to its popularity around the world, black tea has become a staple in many cultures. Whether you prefer a strong, malty Assam tea or a light, floral Darjeeling tea, there is a black tea out there for everyone. With its antioxidant properties, heart health benefits, and immune-boosting compounds, black tea is a great addition to a healthy lifestyle. So next time you're looking for a hot cup of tea, consider trying a black tea and experience the rich flavors and benefits for yourself.

Black tea is the most widely consumed type of tea in the West, distinguished by its full oxidation process which yields a robust flavor, dark liquor, and higher caffeine content than green or white teas . All true teas come from the Camellia sinensis

plant; black tea is simply the version that has been allowed to fully "brown," similar to a sliced apple exposed to air. dofotea.com Core Characteristics Complete Guide to Black Tea - BornTea

Whether you’re a lifelong fan or just starting to swap your morning coffee for a kettle, there’s something undeniably special about a perfect cup of black tea. It’s more than just a caffeinated kick; it’s a ritual, a history lesson, and a science experiment all in one mug. The Comprehensive Guide to Black Tea: Origins, Science,

Here is a deep dive into the world’s most popular oxidized leaf. The Magic of Oxidation

What makes black tea different from green or white tea? It all comes from the same plant (Camellia sinensis), but black tea undergoes full oxidation.

When the leaves are harvested, they are withered, rolled, and exposed to air. This process turns the leaves from green to a deep, dark brown or black, developing those bold, malty, and sometimes fruity flavors we love. It also gives the tea its signature amber hue and a higher tannin profile, which provides that satisfying "body." The Heavy Hitters: Popular Varieties

If you’re looking to explore, these are the essential profiles to know:

Assam (India): The powerhouse. It’s bold, malty, and brisk. This is usually the base for "Breakfast" blends because it stands up beautifully to milk and sugar.

Darjeeling (India): Known as the "Champagne of Teas." Grown in the foothills of the Himalayas, it’s lighter and more floral, with a distinct "muscatel" (grape-like) finish.

Ceylon (Sri Lanka): Crisp and refreshing. It often has citrusy notes and a bright, golden color.

Lapsang Souchong (China): Not for the faint of heart! These leaves are smoke-dried over pinewood fires, giving the tea a campfire-like, savory aroma.

Earl Grey: Technically a flavored tea, this is a black tea base infused with oil from the rind of Bergamot oranges. Why We Drink It (Beyond the Taste)

Black tea is packed with polyphenols and antioxidants like theaflavins and thearubigins. While the science is always evolving, regular drinkers often enjoy:

Focused Energy: Thanks to the combination of caffeine and L-theanine (an amino acid), black tea provides a "calm alertness" rather than the jittery spike you might get from an espresso.

Heart Health: Studies suggest it may help improve cholesterol levels and lower blood pressure.

Gut Health: The polyphenols can help promote healthy gut bacteria. The Secret to the Perfect Steep

If your tea tastes bitter, you might be over-steeping it! To get the best flavor:

Water Temp: Use boiling water (around 212°F / 100°C). Black tea needs the heat to extract its complex oils.

Time: Aim for 3 to 5 minutes. Any longer and the tannins take over, leading to bitterness.

The Vessel: Warm your teapot or mug with a little splash of hot water before brewing to keep the temperature stable.

Whether you take yours plain, with a slice of lemon, or "builder's style" with a splash of milk, black tea is the ultimate comfort drink. It’s a bridge between cultures and a quiet moment in a busy day.

What’s in your mug today? Are you a purist or an Earl Grey enthusiast?

The Legend of the Golden Leaf

In the misty mountains of China, where the air was sweet with the scent of blooming flowers and the soil was rich with ancient secrets, there was a small village named Wuyuan. For generations, the villagers of Wuyuan had been known for their expertise in growing and processing the finest tea leaves in the land.

In the heart of the village, there lived a young apprentice named Lin. Lin was a curious and ambitious young man, with a passion for tea that rivaled his love for life itself. He spent every waking moment learning the art of tea-making from his wise and venerable master, Old Master Wu.

One day, Old Master Wu called Lin to his side and said, "Today, I will teach you the secret of making the finest black tea in all the land." Lin's eyes widened with excitement as his master led him to a hidden garden deep in the mountains.

In the garden, Lin saw rows of tea plants with leaves that shone like polished jade. Old Master Wu explained that these were the famous Wuyi tea plants, known for their robust flavor and rich aroma. He showed Lin how to pluck the leaves at just the right moment, when the sun was high and the dew was still glistening on the plants.

As they worked, Old Master Wu told Lin the legend of the Golden Leaf. It was said that many years ago, a magical golden leaf had fallen from the heavens and landed on the Wuyi tea plants. From that day on, the tea leaves had taken on a special quality, with a depth of flavor and a richness that was unmatched anywhere else. Heart Health: May lower LDL cholesterol and blood pressure

Lin listened with rapt attention as Old Master Wu explained the process of making black tea. They would allow the leaves to wither in the sun, then roll them to release the enzymes that would turn the leaves a deep reddish-brown color. Next, they would oxidize the leaves, allowing them to develop their complex flavor and aroma.

As the sun began to set, Lin and Old Master Wu made their way back to the village, carrying baskets of freshly picked tea leaves. They worked through the night, processing the leaves and filling the air with the sweet scent of black tea.

The next morning, Lin and Old Master Wu sat down to taste their handiwork. They brewed a pot of the black tea, and as the steam rose, Lin was amazed by the rich, smooth flavor that filled the air. It was as if the Golden Leaf had truly imparted its magic to the tea.

Old Master Wu smiled, his eyes twinkling with pride. "You see, Lin, the secret to making great black tea is not just in the technique, but in the passion and love that you put into it." From that day on, Lin was known throughout the land as a master of black tea, and his tea was sought after by emperors and commoners alike.

Years went by, and Lin continued to perfect his craft, experimenting with different techniques and flavors. But he never forgot the legend of the Golden Leaf, and the magical properties that it was said to have imparted to the Wuyi tea plants. And every time he sipped a cup of his finest black tea, he felt a deep connection to the land, the plants, and the ancient secrets that had been passed down through generations of tea masters.

Across history and culture, has evolved from a practical preservation method into the world's most consumed tea variety. While all tea begins with the Camellia sinensis plant, the defining characteristic of black tea is its full oxidation. This chemical transformation creates a robust, complex beverage that offers unique benefits for both cognitive clarity and physical health. The Alchemy of Oxidation

Unlike green or white teas, black tea undergoes an extensive manufacturing process that fundamentally changes its chemical profile:

Withering and Rolling: Fresh leaves are wilted to reduce moisture and then rolled to rupture cell walls. This exposes enzymes (polyphenol oxidase) to oxygen, initiating a "fermentation" phase.

Polyphenol Transformation: During oxidation, simple catechins found in green tea convert into complex theaflavins and thearubigins. These compounds provide black tea's signature copper-red color and "malty" or "brisk" flavor.

Firing: The process is halted by high-heat drying, which stabilizes the flavor and allows for the long shelf life that historically made it a prime global trade commodity. 6 health benefits of drinking black tea | UCLA Health

In the context of tea, "piece" typically refers to of the black tea leaf , or to an ingredient (like fruit or flower pieces) added to a blend. 1. Leaf Grade and "Pieces"

The term "piece" often describes the size and state of the tea leaves after processing. This significantly affects the flavor, strength, and brewing time of the tea: Broken Leaves

: These are intentionally broken into smaller pieces to allow flavors to release more quickly. Examples include Broken Orange Pekoe (BOP)

, which is commonly used in high-quality tea bags for a robust brew. CTC (Crush, Tear, Curl)

: This processing method mechanically shreds leaves into very fine, uniform pieces. This creates a greater surface area, leading to a faster, stronger, and more astringent infusion, typical for standard commercial tea bags. Fannings and Dust

: These are the smallest pieces—essentially the "crumbs" left over from sorting larger leaf grades. They are used in tea bags because they infuse almost instantly and produce a very dark color. Le T Fine Tea 2. Blends with Added "Pieces"

"Piece" also refers to specific non-tea ingredients added to flavored black tea blends to enhance aroma and taste. Common examples include: Fruit Pieces : Dried bits of apple, peach, lemon peel, or strawberry. Floral Pieces

: Petals from cornflowers, rose hips, or hibiscus often mixed into blends like Tess Pleasure French Earl Grey Spice Pieces

: Whole or crushed pieces of ginger, cinnamon, or cardamom used in Masala Chai Thés & Traditions 3. Packaging Units

Tea Bags - Manchester Breakfast - Black Tea - 10 Pieces - Wright Tea


Cultural and Social Roles

Black tea’s cultural significance is diverse:

Caffeine Content in Black Tea

How much caffeine is in a cup of black tea?

For reference, a cup of green tea averages 20–45 mg. Black tea provides a gentler, longer-lasting energy boost than coffee due to the L-theanine buffering effect.

How to Brew the Perfect Cup of Black Tea

Making great black tea is simple, but most people get one crucial element wrong: water temperature.

Cosmic-ray dataset

The dataset consists of 10% of all the events recorded by the Pierre Auger Observatory that pass high-level quality selection checks (explained below). The periods of data recording are: from January 2004 to August 2018 for the SD1500 events; from December 2004 to December 2017 for the hybrid events (SD1500 & FD); from January 2014 to August 2018 for the SD750 events and for the hybrid events involving the HEAT-Coihueco telescopes. These Open Data have been subjected to the reconstruction procedures used by the Auger Collaboration in their official software [Nucl. Instr. Meth. A 580 (2007) 1485–1496 (arXiv)] and explained in [ JCAP 08(2014) 019 (arXiv)], [ JINST 15 (2020) P10021 (arXiv)] and [ Eur. Phys. J. C 81, 966 (2021) (arXiv)].

Pseudo-raw data for the observed cosmic rays are released in JSON format files, one for each event, named "Auger_yydddsssssxx.json", where "yydddsssssxx" is the "id" number which identifies the event. Files consist of different sections, whose number and type depend on the kind of event. Sections and variables are listed below.

In addition, summary files (CSV format) contain the high level information for each reconstructed event in the specific data sample. More details are also given in the semantics section. Note that events observed by multiple FD sites (Eyes) appear once per Eye in the summary file and this has to be taken into account to avoid double counting.

Download the JSON pseudo-raw data for all cosmic ray events (826 MB - individual event JSON data can also be downloaded individually from the event display page).

Download the CSV summary files (8 MB). This file includes all the reconstruction information and should be enough for most physics analyses.

All Auger Open Data have a DOI that you are requested to cite in any applications or publications. The DOI of the main dataset is 10.5281/zenodo.4487612, which always points to the current version. The Auger Collaboration does not endorse any work, scientific or otherwise, produced using these data, even if available on, or linked from, this portal.

How were the cosmic-ray Open Data selected?

The Open Data includes 10% of the data set used in the Auger physics analyses presented at the International Cosmic Ray Conference in 2019. They correspond to the events for which the identification number ("sdid") ends with a zero.

The Open Data recorded with the water-Cherenkov detector arrays are the result of a set of selection criteria applied to detected events. The first requires that the WCD with the highest signal, or closest to the core, is surrounded by a hexagon of six stations that are operational. This requirement ensures adequate sampling of the shower and allows for the evaluation of the aperture of the surface detector in a purely geometrical manner in the energy regime where the array is fully efficient [Nucl.Instrum.Meth.A 613 (2010) 29-39 (arXiv), JCAP 08(2014) 019 (arXiv)], [ Eur. Phys. J. C 81, 966 (2021) (arXiv)]. The detection-efficiency of the SD1500 array is greater than 97% for events with energy above 2.5 x 1018eV arriving from a zenith angle (θ) less than 60°, and 4 x 1018 eV for showers arriving between 60° and 80°. For the SD750 array, the detection efficiency becomes greater than 98% at around 1017eV.

The Open Data of the surface detector arrays have also been subjected to criteria that guarantee good performance of operation: for example, time intervals during which the data acquisition was unstable are excluded; photomultipliers with unstable baseline, loss of calibration data, unstable ratio between high- and low-gain channels, etc., are also excluded.

The Open Data for the hybrid events are selected by requiring the fulfillment of several criteria, including hardware status (at the level of the telescope and pixels) and requiring the quality of the reconstruction of shower geometry and profile (including uncertainties associated with the energy and depth of maximum). Additionally, the atmospheric characterization (including information on the presence of aerosols and clouds, and the vertical optical transparency) is taken into account. Specific fiducial volume cuts are applied for different analyses in order to achieve uniform acceptance and minimize the uncertainties on the corresponding observables. Events passing the selection for the energy spectrum, the calibration, and/or the depth of maximum analyses, are flagged accordingly ("hdSpectrum","hdCalib","hdXmax").

How were the cosmic-ray Open Data reconstructed?

To illustrate the reconstruction procedures used for events recorded with WCD arrays and with the air-fluorescence telescopes (and the related variables) two exemplary events are used. One (event 81847956000) triggered simultaneously the SD1500 array and two FD sites, the other (event 141476578900) triggered the SD750 array and the HEAT-Coihueco telescopes. The figures are extracted from the event-display, where these events are available: event 81847956000, event 141476578900.


Footprint of an extensive air shower hitting WCD stations in the SD750 array (see text)


Footprint of an extensive air shower hitting WCD stations in the SD1500 array (see text)

In the adjacent figures the ground view of each event is shown. The colored squares indicate the FD sites that observed the shower. The colored dots correspond to SD1500 (SD750) stations which were hit by the shower particles and that have been selected for the reconstruction process ("recstations"). The areas of the dots are proportional to the logarithm of the magnitude of the signal sizes, while the colors represent the time of arrival ("t") at the different stations (green: early stations; red: late stations). The grey dots indicate detectors which have recorded no signal, while the black dots represent those which, even if a signal was recorded, were not part of the shower event ("isSelected=0"), but due to an unassociated cosmic ray (usually a muon). The position of the core ("x", "y", "z"), where the highest signal would be observed, is marked by the head of the blue arrow, which indicates the azimuth angle ("phi") of the shower direction of arrival.

The signal timing and signal sizes measured in each selected station, as well as the positions of the stations (the stations coordinates can be found in sdMap.csv), are the inputs for the reconstruction of the events [JINST 15 (2020) P10021 (arXiv)].

The signal features are computed from the output of the flash analogue-to-digital converters (FADCs) associated with each photomultiplier (PMT). Examples of such signals in two stations in the event are displayed in the figure below.


FADC traces of the PMTs signals in two different WCD stations hit by the shower

The FADC trace, shown for each of the 3 PMTs with different colors, are for a station 565 m away from the core (top figure) and one 2602 m away (bottom figure). They are expressed in terms of VEMs (Vertical Equivalent Muons) where one VEM is the signal due to a single muon traversing a detector. The FADCs are digitised so as to give a measurement every 25 ns. The traces from the closer detector are relatively smooth and are compressed into ~1000 ns while at the greater distance the signal arrives over a period of ~4000 ns. Most of the large spikes seen in the more distant FADC signals are probably due to muons which cross the detector, though high-energy electrons that would penetrate the full depth of the water may be present close to the shower axis and are expected to arrive early in the time window. More typically, however, the mean energy of an electron or photon in a shower at several 100 metres from the shower axis is ~10 MeV in contrast to typical muon energies of > 500 MeV. The energy loss of a relativistic particle that traverses a tank in a vertical direction is ~250 MeV.

The signal timing, in terms of start- and stop-times (located at "signalStartBin", "signalStopBin" in the trace, respectively), is determined from a separate analysis of the structures of the FADC traces, after the subtraction of the baselines, in the high-gain channel of each working PMTs in a station. By merging the extracted information from the PMTs, the start-time ("t") that is determined represents the best estimate of the beginning of the passing shower front. The procedure applied to determine the stop-time ensures that all particles belonging to the shower are included while excluding as many accidental signals as possible. The signal size ("signal") is obtained by integrating the final trace (converted in VEMs), which consists of the bin-by-bin average of the traces of the PMTs in the high-gain channel ("sat=0"), or low-gain channel if the high-gain is saturated ("sat=1", "sat=2"), between the determined start and stop times.

To initiate the reconstruction of the zenith and azimuth angles of the shower arrival direction ("theta", "phi"), an estimation of the location of the core on the ground is obtained as the signal-weighted center-of-mass of the selected stations in an event. Then the start-times of the signals in each station are fitted to a model that describes the shower particles as moving with the speed of light in a curved shower front. Thus the two directional cosines and the time at which the core strikes the ground are determined. The radius of curvature ("R") is also set as a free parameter when five or more stations are selected for the event reconstruction. The arrival direction is determined to a precision of about 1°, a figure that falls as the energy (and hence the multiplicity of stations triggered) rises.


Fall-off of the signals size as a function of the distance to the shower core (blue dots) fitted with the lateral distribution function (yellow line)

The reconstruction of the arrival direction of the shower is followed by the calculation of the energy estimator and of the position of the impact point at the ground ("x", "y", "z"). For vertical events, a fit to a lateral distribution function (ldf) is performed. In the adjacent figure the fall-off of the signal sizes (blue dots) with distance ("spDistance"), in a plane perpendicular to the direction of the shower, is shown together with a yellow line that defines the ldf used to fit the event. The signal at an “optimal distance”, which depends predominantly on the spacing between detectors and can be found accurately independent of knowledge of the exact shape of the ldf, represents the shower size and acts as a surrogate for the energy of the primary particle which has initiated the shower. For a spacing of 1500 m the optimal distance is 1000 m, thus the reference signal is S(1000), ("s1000"), while for a spacing of 750 m the optimal distance is 450 m and the reference signal is is S(450), ("s450"). The uncertainty in the measurement of S(1000) decreases from 15% at a shower size of 10 VEM (roughly corresponding to E ~ 2.5 x 1018 eV) to 5% at the highest shower sizes. The uncertainty on the impact point is of order 50 m. The reference signal is influenced by changes in atmospheric conditions that affect shower development [JINST 12 (2017) P02006 (arXiv)] and by the geomagnetic field that impacts on the shower particle-density [JCAP11 (2011) 022 (arXiv)]. Corrections of order 2% and 1% for the atmospheric and geomagnetic effects ("wcorr", "gcorr"), respectively, are made to the reference signal.

black tea

Parameterized densities of muons for a 10 EeV proton shower at zenith angles of 60°, 70° and 80°arriving from azimuth, φ = 0°. Radial units are in kilometers. The coordinate system is defined in the plane perpendicular to the shower direction with the y-axis parallel to the projection of the Earth’s magnetic field on that plane. The magnitude of the muon densities are indicated along the solid line.

For inclined events, the method used for reconstruction of the energy estimator and core position is modified. Due to their long path in the atmosphere, muons, the particles that contribute most of the signal for inclined showers, are deflected in the Earth’s magnetic field. As a result, the near-cylindrical symmetry of the showers is lost and the distribution of the signals at the ground is described with a 2D ldf (so-called muon map). By scaling the muon map of a reference proton shower at 1019 eV an energy estimator, N19 ("n19"), is obtained. The uncertainty in N19 decreases from 13% at E ~ 4 x 1018 eV to 4% at the highest energy. The uncertainty on the impact point is of order 100 m [ JCAP 08(2014) 019 (arXiv)].

For a cosmic ray of a given energy, the shower size estimators depend on the zenith angle because, once it has passed the depth of shower maximum, a shower is attenuated as it traverses the atmosphere. The intensity of cosmic rays, defined as the number of events per steradian above some S(1000)/S(450)/ N19 threshold, is thus dependent on zenith angle. Given the highly isotropic flux, the intensity is expected to be independent from the zenith angle after correction for the attenuation. Based on this principle, an empirical procedure, the so-called Constant Intensity method, is used to determine the attenuation curve as a function of the zenith angle and therefore an energy estimator, independent of the zenith angle. This can be thought as being the signal at 1000 (450) meters, or N19, that a shower would have produced had it arrived at 38° (35°) or 68°, the median angles of the zenith distribution for the SD1500 (SD750) array in the respective angular ranges (vertical or inclined). The energy ("energy") associated with the SD event is derived from a calibration between the energy estimator S38 (S35) or N68, "s38" ("s35") or "n68", and the energy measured by the FD ("totalEnergy") in golden-hybrid events. The SD1500 energy resolution is about 20% at 2x1018 eV and about 7% above 2x1019 eV. The systematic uncertainty on the energy scale is 14% [Physical Review D 102, 062005 (2020) (arXiv)]. The SD750 energy resolution is about 22% at 1017 eV and about 12% above 1018 eV [ Eur. Phys. J. C 81, 966 (2021) (arXiv)].
Camera view for Los Leones
Camera view for Coihueco
Camera view for HEAT-Coihueco

In the adjacent figure the shower images observed with the Los Leones, Coihueco, and HEAT-Coihueco fluorescence telescopes are displayed. The colors show the time at which the light reaches each pixel ("pixelTime"). The trigger conditions require some pixels to be aligned, but background light can also be recorded (the variable "pixelStatus" will also tell up to which level they are used to reconstruct the shower).

Together with the telescope position, the direction that the pixels point to in the sky (shown in Elevation and Azimuth angles -- from fdPixelMap.csv) determine a plane containing the shower development in the atmosphere ("SDP") . The shower axis within this plane is obtained from the time of arrival of the light at the camera ("TimeFit"), summing the contributions of two distances traveled at the speed of light: the distance crossed by the shower front to a point where light is emitted and the distance this light crosses to the telescope. The time at which the shower front reaches the ground, given by the timing information from the WCD station with the highest signal ("hottestStationId"), sets a strong constraint on the hybrid geometrical reconstruction, (providing "theta", "phi", "x", "y", "z"). For this event, the hottest WCD station is found at ("distSdpStation") around 500 m from the shower detector plane defined with Los Leones and around 250 m for the plane defined with Coihueco (at slightly larger distances from the reconstructed shower axis, "distAxisStation").

The next figure shows the energy deposited ("energyDepositProf") in the atmosphere as a function of the slant depth crossed by the cosmic ray ("atmDepthProf"), as seen independently in the two FD sites. LL is shown in blue and CO in green: the density of points and the uncertainty changes with the position from which the shower is seen.

The integral of this curve gives a direct measurement of the calorimetric energy ("calEnergy") of the primary particle, while the depth at which the maximum of the energy deposition occurs ("xmax") is used to infer the primary particle properties. The reconstruction of each point in the profile from the light seen on the camera ("pixelCharge") depends on the distance to the telescope and on the height in the atmosphere at which the energy is deposited ("distXmax" and "heightXmax").

The detected fluorescence light is proportional to the energy deposition and is emitted isotropically. Cherenkov light is emitted in the forward direction and enters the telescope directly when the shower axis is viewed from the telescope at a small angle ("minViewAngle"). It can also be scattered and reach the telescope at later times, which usually accounts for a fraction of the total detected photons ("cherenkovFraction"). For this example, the minimum viewing angles are 18° and 52°, at LL and CO, respectively; with corresponding Cherenkov fractions of 17% and 7%. Both Fluorescence and Cherenkov light are used in the reconstruction [Nucl.Instrum.Meth.A 798 (2015) 172-213 (arXiv)]. The light is attenuated and scattered when crossing the atmosphere, so both the distance traveled and the atmospheric parameters must be taken into account when estimating the expected number of detected photons that correspond to the emission at each position in the shower development, which is proportional to the deposited energy. The energy deposited per unit depth (dE/dX) in the atmosphere increases, at first, with the multiplication of particles in the shower, and then decreases as the energy loss by ionisation starts to exceed that by Bremsstrahlung. This behavior gives rise to a reasonably universal profile shape, where the position of the maximum Xmax depends on the primary particle type (and its energy). The shape of the profile is described by xmax and the corresponding dEdXmax and two other variables (upsL and uspR) [JCAP 03 (2019) 018 (arXiv)]. The integration of the profile provides a direct calorimetric measurement of the total energy of the primary cosmic ray (calEnergy), pending the correction from the energy taken away by muons (that can be partially detected in the SD) and neutrinos (which will go undetected) [Phys. Rev. D 100, 082003 (2019) (arXiv)] to finally obtain the totalEnergy.

The Comprehensive Guide to Black Tea: Origins, Science, and Culture

Black tea is one of the most widely consumed beverages in the world, second only to water. Known for its bold flavor and deep amber color, it accounts for more than 78% of global tea consumption. While all "true" teas originate from the same plant—Camellia sinensis—it is the unique processing and full oxidation that gives black tea its signature strength and complexity. 1. From Leaf to Cup: The Production Process

Unlike green tea, which is steamed or pan-fired to prevent oxidation, black tea is allowed to fully oxidize. This transformation involves four key stages:

Withering: Freshly plucked leaves are spread out to lose moisture, making them pliable for rolling.

Rolling: The withered leaves are bruised or crushed to break cell walls, releasing enzymes that initiate the oxidation process.

Oxidation (Fermentation): Leaves are exposed to air in a temperature-controlled environment. During this stage, catechins convert into theaflavins and thearubigins, which create the tea's dark color and robust taste.

Drying: The final step applies heat to stop oxidation and lock in the flavor profile. 2. Popular Varieties and Flavor Profiles

Black tea flavors vary significantly based on terroir, leaf variety (assamica vs. sinensis), and processing.

Black tea is the most oxidized of all "true" teas, known for its bold flavor, dark amber infusion, and significant health profile . While all true teas come from the Camellia sinensis

plant, black tea’s unique character is defined by a complete oxidation process that transforms its chemical structure and color. Harney & Sons Fine Teas The Core Features of Black Tea Description

Fully oxidized, which darkens the leaves and creates deep, robust flavors. Flavor Profile

Ranges from malty and earthy to fruity, floral, or even smoky.

Higher than green or white tea (approx. 40–70 mg per 8oz cup), providing a sustained energy boost. Appearance

Leaves are dark brown or black; the brewed liquor is typically rich amber to burgundy. Processing: From Leaf to Brew

The distinct characteristics of black tea are achieved through a four-step traditional method: What is black tea? All you need to know. - Newby Teas

6. Health Benefits

Black tea is rich in theaflavins and thearubigins (antioxidants formed during oxidation). Research suggests:

Note: High tannins can inhibit iron absorption. If iron-deficient, wait 1+ hour after meals to drink.

5. Yunnan Black Tea (Dian Hong)

Contemporary Trends

Recent trends reshape black tea’s role in global consumption:

Conclusion Black tea is more than a beverage: it is a product of intricate agricultural processes, a driver of historical trade and colonial economies, and a living element of countless cultural rituals worldwide. Its flavor diversity, adaptability to various preparations, and substantial global market ensure that black tea will remain central to social life and economic activity, even as producers and consumers confront environmental and social challenges that require innovation and responsibility.

The Rich History and Benefits of Black Tea

Black tea, one of the most widely consumed types of tea globally, has a rich history dating back to the 17th century. Originating in China, black tea has become an integral part of various cultures, particularly in the UK, India, and Sri Lanka. The unique processing method, which involves withering, rolling, oxidation, and firing, sets black tea apart from other types of tea, such as green, white, and oolong.

History of Black Tea

The history of black tea dates back to the 1600s, during the Ming dynasty in China. Before this period, tea was only consumed in its green form, which was primarily produced in China. However, with the rise of European trade, the demand for a more robust and durable tea increased. Chinese tea producers experimented with different processing methods, leading to the creation of black tea.

The production of black tea involves four main steps:

  1. Withering: Freshly harvested tea leaves are spread out to allow excess moisture to evaporate.
  2. Rolling: The withered tea leaves are rolled to release the enzymes that cause oxidation.
  3. Oxidation: The rolled tea leaves are left to oxidize for a period of time, which turns the leaves dark brown to black in color.
  4. Firing: The oxidized tea leaves are heated to stop the oxidation process, resulting in a dry and stable product.

Types of Black Tea

Black tea comes in a variety of flavors and styles, depending on the region in which it is produced. Some of the most popular types of black tea include:

  1. Assam Tea: Produced in the Assam region of India, Assam tea is known for its strong, malty flavor and rich, full-bodied taste.
  2. Darjeeling Tea: Grown in the Himalayan foothills of India, Darjeeling tea is famous for its light, floral flavor and hint of sweetness.
  3. Ceylon Tea: Produced in Sri Lanka, Ceylon tea is known for its balanced flavor and hint of spice.
  4. Keemun Tea: Originating from China, Keemun tea is known for its smooth, fruity flavor and floral aroma.
  5. Lapsang Souchong Tea: Smoked over pinewood fires, Lapsang Souchong tea has a distinctive smoky flavor.

Health Benefits of Black Tea

Black tea has been associated with numerous health benefits, including:

  1. Antioxidants: Black tea contains a high amount of antioxidants, which help protect the body against free radicals and oxidative stress.
  2. Cardiovascular Health: Regular consumption of black tea has been shown to lower cholesterol levels and reduce the risk of heart disease.
  3. Anti-Inflammatory Properties: Black tea contains polyphenols, which have anti-inflammatory properties and may help reduce the risk of certain cancers.
  4. Improved Cognitive Function: The caffeine and L-theanine in black tea may help improve focus, concentration, and memory.
  5. Digestive Health: Black tea has been shown to have prebiotic properties, which may help support gut health.

Preparation and Serving Suggestions

Black tea can be enjoyed in various ways, depending on personal preference. Here are some popular ways to prepare and serve black tea:

  1. Traditional English Breakfast: Brew strong black tea with milk and sugar for a classic breakfast tea.
  2. Afternoon Tea: Serve black tea with milk, sugar, and a selection of finger sandwiches, scones, and pastries.
  3. Iced Tea: Brew strong black tea and serve over ice with lemon or fruit infusions.
  4. Tea Latte: Mix black tea with steamed milk and a sweetener, such as honey or sugar.

Conclusion

Black tea, with its rich history, diverse flavor profiles, and potential health benefits, is a popular beverage enjoyed worldwide. Whether you prefer a strong and malty Assam tea or a light and floral Darjeeling tea, there's a black tea to suit every taste and preference. Experiment with different brewing methods, flavor combinations, and serving suggestions to discover the perfect cup of black tea for you.

The Rich History and Benefits of Black Tea

Black tea, one of the most widely consumed types of tea globally, has a rich history dating back to the 16th century. Originating in China, black tea has become a staple in many cultures around the world, particularly in the UK, India, and Sri Lanka. This type of tea is known for its distinct flavor profile, which is achieved through a unique processing method that involves fermentation. In this article, we will explore the history of black tea, its production process, and its numerous health benefits.

History of Black Tea

Black tea has its roots in China during the Ming dynasty (1368-1644). It was initially called "red tea" due to the reddish-brown color of the leaves. However, as trade and cultural exchange increased, black tea spread to other parts of Asia, including India and Sri Lanka. The British, who were major tea consumers, played a significant role in popularizing black tea in the 18th century. They established tea plantations in India and Sri Lanka, which became major producers of black tea.

The production of black tea involves several steps, including withering, rolling, oxidation, and firing. The leaves are first withered to remove excess moisture, then rolled to release the enzymes that cause oxidation. This process, which can take several hours, gives black tea its characteristic flavor and color. Finally, the leaves are fired in hot ovens to stop the oxidation process and preserve the tea.

Production Process

The production process of black tea is what sets it apart from other types of tea, such as green tea and white tea. While green tea is steamed or pan-fried to prevent oxidation, black tea is allowed to oxidize, which changes the flavor and color of the leaves. The level of oxidation can vary depending on the manufacturer, but most black teas are oxidized for several hours to achieve the desired flavor profile.

There are several types of black tea, including:

Health Benefits

Black tea has numerous health benefits, making it a popular choice among tea enthusiasts. Some of the key benefits include:

Caffeine Content

Black tea contains a moderate amount of caffeine, which can vary depending on the brand and brewing method. On average, an 8 oz cup of black tea contains around 40-70 mg of caffeine. This is less than coffee, but more than green tea. The caffeine content in black tea can provide a gentle energy boost and improve mental alertness.

How to Brew Black Tea

Brewing black tea is a straightforward process that requires some basic equipment and attention to detail. Here are some tips:

Conclusion

Black tea is a rich and complex type of tea with a long history and numerous health benefits. From its origins in China to its popularity around the world, black tea has become a staple in many cultures. Whether you prefer a strong, malty Assam tea or a light, floral Darjeeling tea, there is a black tea out there for everyone. With its antioxidant properties, heart health benefits, and immune-boosting compounds, black tea is a great addition to a healthy lifestyle. So next time you're looking for a hot cup of tea, consider trying a black tea and experience the rich flavors and benefits for yourself.

Black tea is the most widely consumed type of tea in the West, distinguished by its full oxidation process which yields a robust flavor, dark liquor, and higher caffeine content than green or white teas . All true teas come from the Camellia sinensis

plant; black tea is simply the version that has been allowed to fully "brown," similar to a sliced apple exposed to air. dofotea.com Core Characteristics Complete Guide to Black Tea - BornTea

Whether you’re a lifelong fan or just starting to swap your morning coffee for a kettle, there’s something undeniably special about a perfect cup of black tea. It’s more than just a caffeinated kick; it’s a ritual, a history lesson, and a science experiment all in one mug.

Here is a deep dive into the world’s most popular oxidized leaf. The Magic of Oxidation

What makes black tea different from green or white tea? It all comes from the same plant (Camellia sinensis), but black tea undergoes full oxidation.

When the leaves are harvested, they are withered, rolled, and exposed to air. This process turns the leaves from green to a deep, dark brown or black, developing those bold, malty, and sometimes fruity flavors we love. It also gives the tea its signature amber hue and a higher tannin profile, which provides that satisfying "body." The Heavy Hitters: Popular Varieties

If you’re looking to explore, these are the essential profiles to know:

Assam (India): The powerhouse. It’s bold, malty, and brisk. This is usually the base for "Breakfast" blends because it stands up beautifully to milk and sugar.

Darjeeling (India): Known as the "Champagne of Teas." Grown in the foothills of the Himalayas, it’s lighter and more floral, with a distinct "muscatel" (grape-like) finish.

Ceylon (Sri Lanka): Crisp and refreshing. It often has citrusy notes and a bright, golden color.

Lapsang Souchong (China): Not for the faint of heart! These leaves are smoke-dried over pinewood fires, giving the tea a campfire-like, savory aroma.

Earl Grey: Technically a flavored tea, this is a black tea base infused with oil from the rind of Bergamot oranges. Why We Drink It (Beyond the Taste)

Black tea is packed with polyphenols and antioxidants like theaflavins and thearubigins. While the science is always evolving, regular drinkers often enjoy:

Focused Energy: Thanks to the combination of caffeine and L-theanine (an amino acid), black tea provides a "calm alertness" rather than the jittery spike you might get from an espresso.

Heart Health: Studies suggest it may help improve cholesterol levels and lower blood pressure.

Gut Health: The polyphenols can help promote healthy gut bacteria. The Secret to the Perfect Steep

If your tea tastes bitter, you might be over-steeping it! To get the best flavor:

Water Temp: Use boiling water (around 212°F / 100°C). Black tea needs the heat to extract its complex oils.

Time: Aim for 3 to 5 minutes. Any longer and the tannins take over, leading to bitterness.

The Vessel: Warm your teapot or mug with a little splash of hot water before brewing to keep the temperature stable.

Whether you take yours plain, with a slice of lemon, or "builder's style" with a splash of milk, black tea is the ultimate comfort drink. It’s a bridge between cultures and a quiet moment in a busy day.

What’s in your mug today? Are you a purist or an Earl Grey enthusiast?

The Legend of the Golden Leaf

In the misty mountains of China, where the air was sweet with the scent of blooming flowers and the soil was rich with ancient secrets, there was a small village named Wuyuan. For generations, the villagers of Wuyuan had been known for their expertise in growing and processing the finest tea leaves in the land.

In the heart of the village, there lived a young apprentice named Lin. Lin was a curious and ambitious young man, with a passion for tea that rivaled his love for life itself. He spent every waking moment learning the art of tea-making from his wise and venerable master, Old Master Wu.

One day, Old Master Wu called Lin to his side and said, "Today, I will teach you the secret of making the finest black tea in all the land." Lin's eyes widened with excitement as his master led him to a hidden garden deep in the mountains.

In the garden, Lin saw rows of tea plants with leaves that shone like polished jade. Old Master Wu explained that these were the famous Wuyi tea plants, known for their robust flavor and rich aroma. He showed Lin how to pluck the leaves at just the right moment, when the sun was high and the dew was still glistening on the plants.

As they worked, Old Master Wu told Lin the legend of the Golden Leaf. It was said that many years ago, a magical golden leaf had fallen from the heavens and landed on the Wuyi tea plants. From that day on, the tea leaves had taken on a special quality, with a depth of flavor and a richness that was unmatched anywhere else.

Lin listened with rapt attention as Old Master Wu explained the process of making black tea. They would allow the leaves to wither in the sun, then roll them to release the enzymes that would turn the leaves a deep reddish-brown color. Next, they would oxidize the leaves, allowing them to develop their complex flavor and aroma.

As the sun began to set, Lin and Old Master Wu made their way back to the village, carrying baskets of freshly picked tea leaves. They worked through the night, processing the leaves and filling the air with the sweet scent of black tea.

The next morning, Lin and Old Master Wu sat down to taste their handiwork. They brewed a pot of the black tea, and as the steam rose, Lin was amazed by the rich, smooth flavor that filled the air. It was as if the Golden Leaf had truly imparted its magic to the tea.

Old Master Wu smiled, his eyes twinkling with pride. "You see, Lin, the secret to making great black tea is not just in the technique, but in the passion and love that you put into it." From that day on, Lin was known throughout the land as a master of black tea, and his tea was sought after by emperors and commoners alike.

Years went by, and Lin continued to perfect his craft, experimenting with different techniques and flavors. But he never forgot the legend of the Golden Leaf, and the magical properties that it was said to have imparted to the Wuyi tea plants. And every time he sipped a cup of his finest black tea, he felt a deep connection to the land, the plants, and the ancient secrets that had been passed down through generations of tea masters.

Across history and culture, has evolved from a practical preservation method into the world's most consumed tea variety. While all tea begins with the Camellia sinensis plant, the defining characteristic of black tea is its full oxidation. This chemical transformation creates a robust, complex beverage that offers unique benefits for both cognitive clarity and physical health. The Alchemy of Oxidation

Unlike green or white teas, black tea undergoes an extensive manufacturing process that fundamentally changes its chemical profile:

Withering and Rolling: Fresh leaves are wilted to reduce moisture and then rolled to rupture cell walls. This exposes enzymes (polyphenol oxidase) to oxygen, initiating a "fermentation" phase.

Polyphenol Transformation: During oxidation, simple catechins found in green tea convert into complex theaflavins and thearubigins. These compounds provide black tea's signature copper-red color and "malty" or "brisk" flavor.

Firing: The process is halted by high-heat drying, which stabilizes the flavor and allows for the long shelf life that historically made it a prime global trade commodity. 6 health benefits of drinking black tea | UCLA Health

In the context of tea, "piece" typically refers to of the black tea leaf , or to an ingredient (like fruit or flower pieces) added to a blend. 1. Leaf Grade and "Pieces"

The term "piece" often describes the size and state of the tea leaves after processing. This significantly affects the flavor, strength, and brewing time of the tea: Broken Leaves

: These are intentionally broken into smaller pieces to allow flavors to release more quickly. Examples include Broken Orange Pekoe (BOP)

, which is commonly used in high-quality tea bags for a robust brew. CTC (Crush, Tear, Curl)

: This processing method mechanically shreds leaves into very fine, uniform pieces. This creates a greater surface area, leading to a faster, stronger, and more astringent infusion, typical for standard commercial tea bags. Fannings and Dust

: These are the smallest pieces—essentially the "crumbs" left over from sorting larger leaf grades. They are used in tea bags because they infuse almost instantly and produce a very dark color. Le T Fine Tea 2. Blends with Added "Pieces"

"Piece" also refers to specific non-tea ingredients added to flavored black tea blends to enhance aroma and taste. Common examples include: Fruit Pieces : Dried bits of apple, peach, lemon peel, or strawberry. Floral Pieces

: Petals from cornflowers, rose hips, or hibiscus often mixed into blends like Tess Pleasure French Earl Grey Spice Pieces

: Whole or crushed pieces of ginger, cinnamon, or cardamom used in Masala Chai Thés & Traditions 3. Packaging Units

Tea Bags - Manchester Breakfast - Black Tea - 10 Pieces - Wright Tea


Cultural and Social Roles

Black tea’s cultural significance is diverse:

Caffeine Content in Black Tea

How much caffeine is in a cup of black tea?

For reference, a cup of green tea averages 20–45 mg. Black tea provides a gentler, longer-lasting energy boost than coffee due to the L-theanine buffering effect.

How to Brew the Perfect Cup of Black Tea

Making great black tea is simple, but most people get one crucial element wrong: water temperature.

Auxiliary files

In addition to data, auxiliary data are available here, namely the list of the positions of the SD detectors and of the FD pixels, as well as the SD exposure and the FD acceptance.

The "sdMap.csv" file contains the position in UTC coordinate system of all stations of the surface detector and time period of activity, in the following format:

  • id : identification number of the station
  • northing,easting,altitude: UTC coordinates [m]
  • start: GPS time of the first event detected by the station
  • stop: GPS time of the last event detected by the station. The value is 1 if the station is still in operation
  • sd1500: the value is 1 if the station is part of the SD1500 array
  • sd750: the value is 1 if the station is part of the SD750 array

The "fdPixelMap.csv" file contains information about the position of a pixel in the FD telescopes and its pointing direction:

  • pixel: identification number of the pixel: [0-2639] for eyes 1-4, [0, 1319] for eye 5, [0-3959] for eye 6
  • eye: identification number of the FD site [1-6]
  • pixelTel: identification number of the pixel in an FD telescope [1-440]
  • tel: identification number of the telescope [1-6]
  • col,row: number of column [1-20] and row [1-22] of the pixel in the telescope
  • backwallAngle: angle of the right wall of the FD site with respect to the East (backwallAngle = 0), growing anticlockwise [deg]
  • elevation,azimuth: pointing direction of the pixel [deg]

The exposure files ("sd1500exposure.csv", "sd1500exposureInclined.csv" and "sd750exposure.csv") contain, for each SD event, the value of the exposure cumulated up to the time of its detection. Above the full efficiency threshold, (2.5 EeV for SD1500 vertical events, 4 EeV for the inclined ones, and 0.1 EeV for SD750 events) the calculation of the exposure is purely geometrical, obtained from the integration of the geometrical aperture over the observation time:

  • gpstime: GPS time
  • sd_exposure: value of the exposure at the corresponding GPS time (taking into account the 10% data released) [km2·sr·yr]
  • sd_exposure_all: full Auger exposure without the 10% rescaling [km2·sr·yr]

The FD-related "fdXmaxAcceptance.csv" and "fdXmaxResolution.csv" files are CSV versions of the Tables Appendix B.II and Appendix B.III as published in [Phys. Rev. D 90, 122005 (2014) (arXiv)] Appendix A. In these tables energy-dependent properties of the acceptance and resolution of FD-reconstructed Xmax are tabulated:

  • The column fields of "fdXmaxAcceptance.csv" are
    • energyBin: index of energy bin
    • lgMinEnergy: start of energy bin [log(E/eV)]
    • lgMaxEnergy: end of energy bin [log(E/eV)]
    • Xacc1: the Xmax value below which acceptance effects become relevant [g/cm2]
    • Xacc1err: statistical error of former [g/cm2]
    • Xacc2: the Xmax value above which acceptance effects become relevant [g/cm2]
    • Xacc2err: statistical error of former [g/cm2]
    • lambda1: exponential slope of acceptance for Xmax < Xacc1 [g/cm2]
    • lambda1err: statistical error of former [g/cm2]
    • lambda2: exponential slope of acceptance for Xmax > Xacc2 [g/cm2]
    • lambda2err: statistical error of former [g/cm2]
  • The column fields of "fdXmaxResolution.csv" are
    • energyBin: index of energy bin
    • lgMinEnergy: start of energy bin [log(E/eV)]
    • lgMaxEnergy: end of energy bin [log(E/eV)]
    • sigma1: width of first Gaussian [g/cm2]
    • sigma1Err: statistical error of former [g/cm2]
    • sigma2: width of second Gaussian [g/cm2]
    • sigma2Err: statistical error of former [g/cm2]
    • f: relative weight between two Gaussians

Download the "sdMap.csv" file.

Download the "fdPixelMap.csv" file.

Download the "fdXmaxAcceptance.csv" file.

Download the "fdXmaxResolution.csv" file.

Download all auxiliary files (400 kB ZIP file).