6 research outputs found
Studien zu optischen Eigenschaften von flüssig Szintillatoren, Elektroniksimulation und Datenanalyse für das Neutrinoexperiment Borexino
No full textBorexino is a state-of-the-art solar neutrino experiment. Many results could be reported, but still some parts of the solar neutrino spectrum remain unseen.
In this thesis, some steps to achieve a better detector understanding are done:
Determining the Birks factor of electron quenching, monitoring the muon tagging efficiency, generating a detector simulation program and performing a neutron production analysis. All this will contribute to a possible detection of CNO and pp neutrinos.Borexino ist ein solares Neutrinoexperiment. Viele Ergebnisse wurden erzielt, dennoch bleiben Bereiche des Neutrinospektrums ungesehen. In dieser Arbeit werden Schritte unternommen, die ein besseres Detektorverständnis erzeugen:
Bestimmung des Birks Faktors für Elektronen, Überwachung der Myon-Nachweis Effizienz, Erzeugung eines Moduls für Detektor-Simulation und Durchführung einer Analyse zur Neutronenproduktion. Dies wird zu einem möglichen Nachweis von CNO und pp Neutrinos beitragen
Gastrodia thilakapremae Atthanagoda, C. Bandara & Kumar. Voucher 2023, sp. nov.
No full text<i>Gastrodia thilakapremae</i> Atthanagoda, C.Bandara & Kumar <i>sp. nov.</i> (Figs. 1 F–K, 4 & 5) <p> <b>Type:—</b> SRI LANKA. Central Province, Kandy District, Kondagala in Loolkandura Estate, 26 May 2022, <i>AKAG12.2022</i> (holotype PDA!; isotype PDA!-spirit); Sabaragamuwa Province, Ratnapura District, Galwangediya, Eratne –Sri Pada trail, Samanala Nature Reserve, 10 June 2022, <i>AKAG13.2022</i> (paratype PDA!; PDA!-spirit).</p> <p> <b>Diagnosis:</b> <i>Gastrodia thilakapremae</i>, a Sri Lankan endemic, is not easy to differentiate from a Japan and Taiwan native <i>G. gracilis</i> Blume (1856: 174) as they look similar in various morphological features, however they are different on a closer look. <i>Gastrodia thilakapremae</i> has green flowers with green opaque petals; triangular floral bracts, 4.5–6 mm long; orange labellum (darker towards apex and fading towards base), length slightly shorter than column with anther cap, almost triangular to ovate in shape abruptly narrowing towards the apex with constrictions on the margins, lacking distinct longitudinal bands of intermittent warts towards the centre, with a pair of triangular lamellae on the centre between the constrictions; hypochile broad (> 2 mm wide) and orange on upper and white on the lower surface; epichile lower margin slightly flat; column with stelidia wings broadening from nearly at the base of the column till just below the apex of stelidia and capsules fusiform, 2.5–3.5 cm long. Whereas, <i>G. gracilis</i> has dull greenish-brown flowers with darker pale brown petals; floral bracts ovate or elliptic shaped, 2–4 mm long; labellum orange with white longitudinal bands before the margin on either side, length slightly longer than the column with anther cap, almost triangular but gradually narrowing towards apex lacking any constrictions on the margin; distinct 5 longitudinal divergent bands of intermittent warts running from base to the middle of the labellum, with a pair of ellipsoid lamellae towards the apex; hypochile narrow (<2 mm wide) and orange on both surfaces; lower margin of epichile raised up to fill the gap caused due to lack of wings on lower margin of the column; column with broadening of stelidia wings not starting from base but after 1/3 rd of the length from base and obovoid or ellipsoid capsules that are 2–2.3 cm long (see Fig. 6).</p> <p> <b>Terrestrial</b>, holomycoheterotrophic herbs, 55–75 cm tall. <b>Rhizome</b> tuberous, ellipsoid, 4–6 cm long, 1.0– 1.3 cm in diameter, sparse hairs dispersed along the gaps between closely placed membranous triangular scales emerging from the nodes. <b>Raceme</b> erect, peduncle 40–46 cm long, glabrous, pale brown or greyish-brown, with 8–10 membranous semi-transparent sheaths; sheaths tubular, pale brown, 5.5–7 mm long. <b>Inflorescence</b> erect with 4–6 flowers, rachis ca. 4–6 cm long. <b>Floral bracts</b> triangular, 4.5–6 mm, acute, dark brown, base surrounding the pedicel. <b>Pedicel</b> dull green-brown to dark brown, verrucose, ca. 4–6 mm long. <b>Flowers</b> resupinate, perianth tube formed by fusion of sepals and petals, apical end partially opened; perianth tube slightly arched downwards, nodding, 2.2–2.5 cm long, up to 1.6–1.8 cm wide, globose, outer surface dull green, verruculose; inner surface pale green; lobe of dorsal sepal broadly ovate, 9–10 × 6 mm, apex obtuse, slightly convex, fleshy, yellowish-green to pale green, margins entire; lobes of lateral sepals broadly ovate, 8–9 × 4.5–5.5 mm, obtuse, fleshy, margins entire, yellow-green on outside, pale green inside; petal lobes 2, orbicular with contracted base, curled, smaller than sepal lobes, 5.5 × 5 mm, obtuse, margin crenate, pale green; labellum adnate to column foot, ovate to rhomboid, 5.5–6.3 mm long, 2.3–4.5 mm wide, enclosed within the perianth tube, orange, longitudinally channeled underneath; epichile abruptly narrowing at the apex, 5.2–5.4 mm long, 3.5–4.5 mm wide, dark orange, apex yellow, irregularly crisped on the margin; hypochile contracted into a claw, ca. 0.6–0.8 mm long, 2.1–2.3 mm wide, pair of lamellae or ridge towards the apex; pair of globular, waxy calli at the base, 1.1–1.3 mm in diameter. <b>Column</b> erect, narrowly ovate to elliptic, 5–5.5 mm long, 3–3.2 mm wide, apex retuse, pale green-white with light brown colored on both sides, bearing stelidia on either sides and a short foot below; stelidia distinct, falcate, spread out, ca. 4.5 × 1.3 mm, apex acute with a pointed tip, base slightly angled, pale greenish; foot short, 1–1.2 mm long, brown-green; rostellum prominent; stigma located towards the base of the column on a raised, but inclined platform. <b>Anther cap</b> cucullate, ca. 2.2 mm in diameter; pollinia 2, clavate, ca. 2 mm long; ovary obconical, 3.5–3.8 mm long, ca. 2 mm wide, dark brown, verrucose, ribbed. <b>Capsule</b> erect, fusiform, verruculose, ca. 2.5–3.5 cm long, 0.7–0.9 cm wide, dark brown with darker stripes, borne on an elongated pedicel; pedicel with capsule up to 4–8 cm long, brown, slender and terete.</p> <p> <b>Phenology:—</b> Flowering and fruiting observed during May to December in separate subpopulations. Flowering season of the subpopulations in Samanala Nature Reserve show wide range than the other population in Loolkandura. Flowering and fruiting individuals were observed during May to November at the Samanala Nature Reserve in different years according to the field observations. The Loolkandura subpopulation flowered in December. However, flowering and fruiting individuals were observed simultaneously in same population.</p> <p> <b>Etymology:—</b> The specific epithet honors Mr. Atthanagoda Kankanamalage Thilakaprema, the second author’s father for his support and guidance.</p> <p> <b>Distribution:—</b> <i>Gastrodia thilakapremae</i> is endemic to Sri Lanka and occurs throughout sub-montane forest at Kondagala in Loolkandura Estate, Kandy District; in the sub-montane and montane forests of the Samanala Nature Reserve in Central Highlands of Sri Lanka at Galwangediya on Kuruwita–Eratne–Sri Pada trail and Mahagalthalawa on Moray Estate–Sri Pada trail in Ratnapura District (Fig. 7).</p> <p> <b>Habitat and ecology:—</b> This species is found on montane and sub-montane forests between 1500–2000 m a.s.l and under the shade of <i>Strobilanthes</i> (Acanthaceae) shrubs among the thick leaf litter. Mostly prefers partially open canopy and humus rich soil. Other notable members of Orchidaceae family sharing the same habitat were, <i>Liparis elliptica</i>, <i>Calanthe masuca</i>, <i>Zeuxine</i> sp. and <i>Oberonia</i> sp. in Samanala Nature Reserve. <i>Oberonia scyllae</i>, <i>Peristylus aristatus</i>, <i>Chiloschista fasciata</i> and <i>Phaius wallichii</i> in Kondagala, Loolkandura Estate.</p> <p> <b>Conservation status:—</b> <i>Gastrodia thilakapremae</i> occurs in both montane and sub-montane forests at 3 different sites in Sri Lanka, one in Kandy District, Central Province and two in Ratnapura District, Sabaragamuwa Province. This species was recorded from Kondagala in Loolkandura Estate in 2012 where it was seen in bloom regularly in 2016, 2018, 2019, 2020, 2021 and 2022 with 4, 6, 2, 11, 5 and 6 individuals respectively (Fig. 8). Two other subpopulations were found in 2020 from Galwangediya area, Eratne–Sri Pada trail and Mahagalthalawa, Moray Estate–Sri Pada trail in Samanala Nature Reserve and both of sites were revisited in 2022. The subpopulation in Galwangediya area, Eratne–Sri Pada trail consisted of 11 mature plants in 2020 and 16 in 2022. Mahagalthalawa subpopulation is the smallest among all with 4 individuals in 2020 and 3 in the following visit in 2022. The habitats of this species in Sri Pada are also threatened due to the clearance of banks and roadsides during the pilgrim season. The population of Kondagala in Loolkandura Estate is faintly protected with a good forest cover but, not safe at all with the human interactions. There is an inferred threat of decline in the quality of habitat. Hence, three sites are considered as three locations. This species may remain dormant with underground tubers, and hence, an optimistic estimate of less than 50 mature individuals has been inferred. The Area of Occupancy (AOO) and the Extent of Occurrence (EOO) were 12 km 2 and ~ 186 km 2 respectively according to GeoCAT (Bachman <i>et al</i>. 2011). Based on available information this species can be assessed as Critically Endangered (CR D) owing to extremely small population size following IUCN guidelines (IUCN 2022).</p> <p> <b>Taxonomic notes:—</b> <i>Gastrodia thilakapremae</i> is morphologically similar with the group of species in <i>Leptogastrodia</i> M.A.Clem & D.L.Jones (≡ <i>Gastrodia</i>), but differs from all other species by having 55–75 cm tall plant habit; 2.2–2.5 cm long, up to 1.6–1.8 cm wide, dull green color flowers with ovate to rhomboid, 5.5–6.3 mm long, 2.3–4.5 mm wide, orange color labellum and 2.5–3.5 cm long, fusiform capsules.</p>Published as part of <i>Bandara, Champika, Atthanagoda, Anusha Gayan, Bandara, Nadeesha Lewke & Kumar, Pankaj, 2023, The study of the tribe Gastrodieae (Orchidaceae, Epidendroideae) in Sri Lanka I: two new species of Gastrodia, pp. 115-130 in Phytotaxa 622 (2)</i> on pages 121-126, DOI: 10.11646/phytotaxa.622.2.2, <a href="http://zenodo.org/record/10084582">http://zenodo.org/record/10084582</a>
Search for modulations of the solar 7Be flux in the next-generation neutrino observatory LENA
No full textA next-generation liquid-scintillator detector will be able to perform high-statistics measurements of the solar neutrino flux. In LENA, solar 7Be neutrinos are expected to cause 1.7×104 electron recoil events per day in a fiducial volume of 35 kilotons. Based on this signal, a search for periodic modulations on a subpercent level can be conducted, surpassing the sensitivity of current detectors by at least a factor of 20. The range of accessible periods reaches from several minutes, corresponding to modulations induced by helioseismic g-modes, to tens of years, allowing to study long-term changes in solar fusion rates
Gastrodia munasinghae Atthanagoda, C. Bandara & Kumar 2023, sp. nov.
No full text<i>Gastrodia munasinghae</i> Atthanagoda, C.Bandara & Kumar <i>sp. nov.</i> (Figs. 1 A–E, 2 & 3) <p> <b>Type:—</b> SRI LANKA, Sabaragamuwa Province, Ratnapura District, Maliboda –Sri Pada trail, Samanala Nature Reserve, 30 March 2022, <i>AKAG10.2022</i> (holotype PDA!; isotype PDA!-spirit); Sabaragamuwa Province, Ratnapura District, in a fragmented forest patch near a tea plantation between Panapola–Pothupitiya, 4 April 2022, <i>AKAG11.2022</i> (paratype PDA!).</p> <p> <b>Diagnosis:—</b> <i>Gastrodia munasinghae</i> is morphologically allied with <i>G. uraiensis</i> Hsu & Kuo (2010: 244) and <i>G. fontinalis</i> Lin (1987: 129) in having similar rough-surfaced brown coloured perianth tube, petals attached at the tip of junction of lateral sepals, orange winged column, stigma placed towards the base of the column and two rounded callus at the base of the labellum, however, the new species differ in having taller plants in former, 10–18 cm tall (vs. 1–4 cm tall plants in <i>G. uraiensis</i> and 7–12 cm tall in <i>G. fontinalis</i>), inflorescence with 4–8 flowers (vs. 1–3(–5) flowers in <i>G. uraiensis</i> and 1–3 flowered in <i>G. fontinalis</i>), labellum 4–4.5 mm long (vs. 6–7 mm long labellum in both <i>G. uraiensis</i> and <i>G. fontinalis</i>) and dull green-blue mesochile and bright orange color epichile in the labellum (vs. reddish brown coloration in <i>G. uraiensis</i> and <i>G. fontialis</i>). <i>G. munasinghae</i> can be also distinguished from <i>G. bambu</i> Metusala (2017: 212) in having 12 mm long, up to 10 mm wide, widely opening smaller flowers (not widely opening, 17 <i>–</i> 20 mm long and 14 <i>–</i> 16 mm wide larger flowers in latter), ovate-orbicular, 4–4.5 mm long and 3–3.2 mm wide labellum (oblonglanceolate, 10 <i>–</i> 12 mm long × 3.5 <i>–</i> 4 mm wide labellum in latter) and erect, 5–5.5 mm long, 2.8–3 mm wide column (slightly arcuate, 10 <i>–</i> 12 mm long, 2 <i>–</i> 2.5 mm wide column in latter).</p> <p> <b>Terrestrial</b> holomycoheterotrophic herbs, 10–18 cm tall. <b>Rhizome</b> tuberous, fusiform or cylindrical, 7–13 × 1.2–2.3 cm, plagiotropic, hairy, membranous triangular scales emerging from the nodes. <b>Raceme</b> erect, peduncle 8–13 cm long, glabrous, pale brown in color, with 3–5 membranous semi-transparent sheaths; sheaths tubular, 4–5.5 mm long. <b>Inflorescence</b> erect with 4–8 flowers, rachis <i>ca</i>. 4–6 cm long. <b>Floral bracts</b> triangular, 5–6 mm, acute, dark greyish brown to dark brown in color, membranous, margin slightly lacerate, base surrounding the pedicel. <b>Pedicel</b> orange-brown, <i>ca.</i> 8–11 mm long, 2.5–3.2 wide. <b>Flowers</b> resupinate, sepals and petals fused to form perianth tube, widely opening; apical part free, forming a five-lobed front; ridges 4; 12 mm long, up to 10 mm wide, outer surface greyish brown, verrucose, inner surface dark brown in color with dull orange-brown under lateral sepals and greyish under dorsal sepal and petals; lobe of dorsal sepal triangularly ovate, 6 × 4.5 mm, obtuse, slightly convex, brown, margins entire; lobes of lateral sepals triangularly ovate, 4.5 × 5 mm, brown, margins entire; petal lobes ovate-elliptic, smaller than sepal lobes, 3.5 × 2 mm, pale brown; labellum adnate to the foot of column, ovate-orbicular, 4–4.5 × 3–3.2 mm, hypochile short, ca. 1 mm long, broader at the base and narrowing towards the epichile, inflated, with 2 globose calli at the base, callus 0.5–0.8 mm in diameter, pale orange-yellow colored with dark brown shiny surface; epichile ovate, 3.5–3.8 mm long, 3.1–3.3 mm wide, obtuse, bright orange at the apex, pale yellowish green along the middle and pale brownish-orange at the base, slightly tapering toward apex with a pair of lamellae or short ridge on the upper surface, longitudinally channeled underneath of the lip from base to the tip. <b>Column</b> erect, 5–5.5 × 2.8–3 mm, whitishcream with grey-brown colored at base, slightly extended into a short foot, ca. 1.5 mm long, 2–2.5 mm wide; stelidia falcate, 2.5–3 × 0.5–0.6 mm, apex acute, extended slightly beyond the anther cap, red-orange; rostellum prominent; stigma located towards the lower half of the column on a raised but slightly inclined and convex platform. <b>Anther cap</b> cucullate, ca. 1.5 mm in diameter. <b>Pollinia</b> 2, clavate, ca. 1.2 mm long. Ovary obconical, 3.5–4 mm long, ca. 2.5 mm wide, dark brown, verrucose, ribbed. <b>Capsule</b> erect, fusiform, verruculose, ca. 2.3–2.7 cm long, 4.5–5 mm wide, on a longer stalk of variable length,> 2 cm long, pale orang-brown with darker stripes, borne on an elongated pedicel, up to 18–32 cm long, pale brown, slender and terete.</p> <p> <b>Phenology:—</b> Flowering and fruiting individuals were observed from early January to April in different subpopulations. The subpopulations in Samanala Nature Reserve begin flowering from January to April and the population in lowland wet zone flowering only in March and April.</p> <p> <b>Etymology:—</b> The specific epithet honors Mrs. Liliyan Chandralatha Munasinghe, the second author’s mother for her unconditional love, support and encouragement.</p> <p> <b>Distribution:—</b> <i>Gastrodia munasinghae</i> is endemic to Sri Lanka and thus far known from the sub-montane forests in Maliboda–Sri Pada trail and Kuruwita–Eratne–Sri Pada trail in Samanala Nature Reserve, Central Highlands of Sri Lanka and fragmented forest patch of the lowland rain forests bordering to a tea plantation near Pothupitiya in Ratnapura District (Fig. 7).</p> <p> <b>Habitat and ecology:—</b> This species grows under the shade of <i>Strobilanthes lupulina</i>, <i>Strobilanthes zeylanica</i> (Acanthaceae) and <i>Ochlandra stridula</i> (Poaceae) species in the lowland forests between 400 and 715 m a.s.l and between 600 and 1000 m a.s.l in foothills of the Adam’s Peak on humus-rich decaying leaf litter. The rhizomes are buried up to 2–4 inches deep in the ground. Other notable Orchidaceae members sharing the same habitat were <i>Sirhookera lanceolata</i>, <i>Zeuxine regia</i>, <i>Anoectochilus</i> sp., <i>Habenaria crinifera</i>, and <i>Oberonia</i> sp. at Pothupitiya and <i>Zeuxine reginasilvae</i> from Maliboda–Sri Pada trail.</p> <p> <b>Taxonomic notes:—</b> <i>Gastrodia munasinghae</i> morphologically close resembles <i>G. uraiensis</i>, <i>G. fontinalis</i> and <i>G. bambu</i> but, is readily distinguished in having 10–18 cm tall plant habit; 4–8 flowered inflorescence; 12 mm long and 10 mm wide flowers; ovate-orbicular, 4–4.5 mm long and 3–3.2 mm wide, dull green-blue colored mesochile and bright orange colored epichile in the labellum and erect, 5–5.5 mm long, 2.8–3 mm wide column. The brown-colored <i>Gastrodia</i> species are morphologically similar to each other on their external appearances but, all species have unique morphological characters and distribution ranges. Clements and Jones (2019), combined this group of brown color <i>Gastrodia</i> species <i>s.l.</i> to the genus <i>Demorchis</i> M.A.Clem. & D.L.Jones. However, this genus is not accepted and synonymized under the genus <i>Gastrodia</i> (Jones & Clements 2004, Clements & Jones 2019, POWO 2023).</p> <p> <b>Conservation status:—</b> <i>Gastrodia munasinghae</i> grows in sub-montane and lowland forests in Sabaragamuwa Province with a small population size of 8 mature individuals found during the first visit in Eratne–Sri Pada trail in Samanala Nature Reserve far back in 2005. Unfortunately, this species was never seen again at this locality after repeated visits until 2022. Later, another subpopulation was discovered in 2012 in Maliboda–Sri Pada trail and the number of mature individuals varied in 2012, 2016, 2020 and 2022 with 6, 3, 8 and 4 respectively (Fig. 8). Recently, another subpopulation has been discovered in 2022 at a fragmented forest patch adjacent to a tea plantation along Panapola– Pothupitiya road, containing 11 flowering individuals. At the first two sites, the habitat is heavily disturbed due to the frequent clearance of the existing pilgrim trails of the Sri Pada (Adam’s Peak) and pollution. The other subpopulation in Pothupitiya is also facing the risk of extinction due to anthropogenic disturbances and land use changes. Area of Occupancy (AOO) and the Extent of Occurrence (EOO) was estimated using GeoCAT (Bachman <i>et al</i>. 2011) as 12 km 2 and ~ 32 km 2 respectively. These mycoheterotrophic species are extremely habitat specific and are susceptible to even minor disturbance. Hence, based on the available data, three sites are considered as three locations. As such the total number of mature individuals encountered so far is 27, however, as these mycoheterotrophic species sometimes remain dormant with underground tubers, hence we optimistically estimate total number of mature individuals to be less than 50. Accordingly, the species is assessed as Critically Endangered (CR D), based on current data and following IUCN guidelines (IUCN 2022).</p>Published as part of <i>Bandara, Champika, Atthanagoda, Anusha Gayan, Bandara, Nadeesha Lewke & Kumar, Pankaj, 2023, The study of the tribe Gastrodieae (Orchidaceae, Epidendroideae) in Sri Lanka I: two new species of Gastrodia, pp. 115-130 in Phytotaxa 622 (2)</i> on pages 116-117, DOI: 10.11646/phytotaxa.622.2.2, <a href="http://zenodo.org/record/10084582">http://zenodo.org/record/10084582</a>
The next-generation liquid-scintillator neutrino observatory LENA
No full textAs part of the European LAGUNA design study on a next-generation neutrino detector, we propose the liquid-scintillator detector LENA (Low Energy Neutrino Astronomy) as a multipurpose neutrino observatory. The outstanding successes of the Borexino and KamLAND experiments demonstrate the large potential of liquid-scintillator detectors in low-energy neutrino physics. Low energy threshold, good energy resolution and efficient background discrimination are inherent to the liquid-scintillator technique. A target mass of 50 kt will offer a substantial increase in detection sensitivity.At low energies, the variety of detection channels available in liquid scintillator will allow for an energy - and flavor-resolved analysis of the neutrino burst emitted by a galactic Supernova. Due to target mass and background conditions, LENA will also be sensitive to the faint signal of the Diffuse Supernova Neutrino Background. Solar metallicity, time-variation in the solar neutrino flux and deviations from MSW-LMA survival probabilities can be investigated based on unprecedented statistics. Low background conditions allow to search for dark matter by observing rare annihilation neutrinos. The large number of events expected for geoneutrinos will give valuable information on the abundances of Uranium and Thorium and their relative ratio in the Earth's crust and mantle. Reactor neutrinos enable a high-precision measurement of solar mixing parameters. A strong radioactive or pion decay-at-rest neutrino source can be placed close to the detector to investigate neutrino oscillations for short distances and sub-MeV to MeV energies.At high energies, LENA will provide a new lifetime limit for the SUSY-favored proton decay mode into kaon and antineutrino, surpassing current experimental limits by about one order of magnitude. Recent studies have demonstrated that a reconstruction of momentum and energy of GeV particles is well feasible in liquid scintillator. Monte Carlo studies on the reconstruction of the complex event topologies found for neutrino interactions at multi-GeV energies have shown promising results. If this is confirmed, LENA might serve as far detector in a long-baseline neutrino oscillation experiment currently investigated in LAGUNA-LBNO
