PoS(ICRC2015)105 http://pos.sissa.it/ , for the LAGO . E-mail: e and Asorey H. c lagoproject.org/collab.html , Masías-Meza J.J. d , c , a f , full list of members and institutions at , Gulisano A.M. c , b , a Due to the geomagnetic shielding, particle detectors locatedof at high cosmic latitudes rays allow the (CRs) observation withAntarctica lower is a energies privileged than place to those study located CRsground having at level. the lowest middle energies The or that Latin can low be AmericanCherenkov latitudes. observed Giant detectors from (WCDs) Observatory Thus, located (LAGO) in consists nine ondetail countries a the of network flux Latin of of America, CRs water- toseveral from study problems ground with of level. extreme astrophysics, The space mainhas physics scientific started and objectives to atmospheric are develop physics. oriented a to SpaceMarambio In address Weather station, particular, program. LAGO located A at projectnode the to install of Antarctic WCDs LAGO. Peninsula, in In is the thisabout Argentinean being the work, developed site, we the as detector, present and the several studiesto first of aspects characterize geomagnetic antarctic of and several atmospheric useful the properties, properties that project, permit ofprovide including us important this insight information location. for Space Results Weather, and from willSun-Earth provide this coupling. knowledge new to LAGO better understand site the will Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. lagoproject.org Instituto Antártico Argentino, DNA, Buenos Aires, Argentina. Instituto de Astronomía y Física delDepartamento Espacio de (UBA-CONICET), Ciencias Buenos de Aires, la Argentina. Atmósfera y los Océanos, Facultad de Ciencias Exactas y Laboratorio de Detección de Partículas y Radiación, Instituto Balseiro y Centro Atómico Departamento de Física and IFIBA, Facultad de Ciencias Exactas y Naturales, Universidad de c f e Bariloche, Bariloche, Argentina. Escuela de FísicaBucaramanga, - Colombia. Universidad Industrial de Santander, Buenos Aires (UBA), Buenos Aires,d Argentina. a b Naturales, Universidad de Buenosc Aires (UBA), Buenos Aires, Argentina. The 34th International Cosmic Ray Conference, 30 July- 6 August, 2015 The Hague, The Netherlands Collaboration [email protected] Dasso S. A Project to Install Water-Cherenkov Detectorsthe in Antarctic Peninsula as part ofDetection the Network LAGO PoS(ICRC2015)105 2 One of the aims of the Latin American Giant Observatory (LAGO, previsouly known as Large The project is operated by the LAGO Collaboration, which is a collaborative, distributed, One the the recent main scientific aims of LAGO is focussed on the study of astroparticles in The trajectory of cosmic rays in the far space ambient of the terrestrial environment is mainly Aperture Gamma ray burst Observatory, seetion [1]) of is an the extended design, astroparticle observatory instalation, to deployment a and global opera- scale. and not centralized network, composedAmerica: Argentina, of Bolivia, researchers Brazil, Colombia, and Ecuador, Guatemala, studentsThey Mexico, have from Peru recently and nine joined Venezuela. institutions countries in in Spain.detectors, The Latin individual LAGO or detection in network is small formed arrays,a by located particle details at of ground level different andlatitudinal LAGO installed distribution detectors (currently at from different at Mexico sites. each toin For Patagonia LAGO the and development site, soon of in this see Antarctica, paper) as [2]. andasl), spans will covering a be an huge The seen extensive range range network of of altitudes geomagnetic coversand (from rigidities sea a reaction cutoff, level at and wide to the different over levels atmosphere. 5000 of m InLAGO absorption addition sites to are the also Antartic starting site orstrategy that of will is LAGO start presented to to in be operate able this to in paper,observations storage, other and LAGO catalogue simulations) (for and can more preserve be details its found see huge in amount [3, [6]. of 4, data 5]). (from both, The the context of space weather and atmosphericwith radiation. decreases Forbush events of (see cosmic e.g., rays [7]) flux areby at associated ground huge level, interplanetary due to transient theother structures, shielding ground in detectors, that the as are solar for instance wind, recorded water produced solar Cherenkov by detectors emission (WCDs) of neutron (e.g., cosmic [8]). monitors rays of Occasionally, as sufficientlevel, energy well can and intensity as be as detected by to by raise(GLEs). radiation neutron levels monitors. at GLEs ground are These of events major arepose interest a called hazard because Ground to an Level astronauts, enhanced Enhancements air relativistic crews,the proton and earliest also and aircraft direct electron electronics, indication flux then can its ofobserved observation with an can proper provide impending surface space detectors radiationglobe, located mainly storm at at (see high different latitude e.g., appropriate regions. [9]). locations of They the can terrestrial be affected by the electromagneticachieve fields significant that effects are on the there. fieldsas (i.e. to Due they be to are significant the notparticles enough sources fact embeded and of that in they electric these have pre-set not fields fields. particles enoughmagnetic or In do energy fields particular, electric not can interplanetary currents), produce conditions very they or importantparticle the can effects modulation presence be on that of these treated can geo- particles, be as and observedgetting passive frequently using closer they ground to produce particle the detectors. terrestrial When surface,of these primary the particles cosmic atmosphere, are rays producing a interact huge withbetween amount the primaries of background secondary and particles particles, the generated atmospheric fromterpretation components. the of interaction the Thus, signals in from order the toas particle be detectors, accurately as able as the to possible LAGO get ones, theseby a it effects, the is correct in necessary atmosphere. in- to particular quantify those produced by the geomagnetic field and WCDs of LAGO in Antarctic Peninsula 1. Introduction PoS(ICRC2015)105 14’24.96"S and ◦ we quantify several effects of the 3 we present a comparison of the pressure 4 we present a Summary and our conclusions of 5 3 Protopype of the detector. Figure 2: Two views of the LAGO Antarctic facility location. Figure 1: we describe the place where the detectors will be installed. We then present 2 37’30.34"W, at 196 meters above sea level. Due to the low temperatures during winter, ◦ The Marambio station of the argentine Antarctic regions is located at Lat. 64 In Section Long. 56 WCDs at Marambio should beand thermally the isolated consequent to lost avoidbe the in uncontrolled allocated. sensitivity. freezing of The To the do laboratoryequipment, water design this, while allows in we the this designed installationthe first facilities of stage Instituto where up only de the to two Astronomía WCDsby three WCDs y will will WCDs the Física be and Centro del deployed, additional Atómico Espacio one Bariloche (IAFE, detector (CAB, UBA-CONICET) provided CNEA). and by This the building another takes one into account the gateway our studies to characterize the site. In particular,height in profile Section observed incannonical the shower local simulators. atmosphere Finally, in with Section the balloons present with paper. the typical ones available in 2. The site at Marambio geomagnetic field on primary particles, and in Section WCDs of LAGO in Antarctic Peninsula PoS(ICRC2015)105 shows the place where the LAGO 1 4 shows a prototype of the detector that was contructed at zenith incidence and eight equispaced incidence azimuth 2 ◦ shows the asymptotic directions of protons arriving at the LAGO Marambio site 3 Asymptotic directions of primary protons before interacting with the geomagnetic field, for dif- The analysis of the data from this WCD at Antartic will allow us to make studies of the In this section we present results of numerical simulations of the trajectory of charged particles Figure (projected on the Earth’s surface) for 15 background cosmic rays rate, similar(e.g., to at the Chacaltaya ones [10]), but that with LAGO higherhaving is counting lower currently rates energies. and making with in the different impact from sites primary particles 3. Geomagnetic field effects: Numerical Simulations arriving to Marambio site, using the MAGCOS codeFor (http://cosray.unibe.ch/ laurent/magnetocosmics). details of the simulationsMarambio, developed but for see another [11]. LAGO sites Similar can studies be found as in the [12]. ones presented here for the Instituto de Astronomía ycan Física be del noticed Espacio, that the in basethe Buenos of level Aires. the of PMT In humidity. is the isolatedzero left Several above Celsius, pieces panel the to of water of container, ensure the the in its figure regimes detector order in quality has to the after decrease been Antarctic suffering soil. tested any at unforeseen temperatures situation well with below low temperatures building will be constructed and Figure Figure 3: ferent energies and different incidence azimuth angles (MAGCOS numerical simulations). accesibility, it has permafrostThe characteristics, whole structure and will be optimal anchored construction tobase the will materials permafrost be with and a elevated assembly. depth 1 ofbuilding m at will least be from one built ground, meter. next The to tobase, steel the diminish and current will the location have impact access of by the of using central snow an scientific external accumulation. pavillon corridor. of Figure The the Marambio new WCDs of LAGO in Antarctic Peninsula PoS(ICRC2015)105 also 4 400 nT. ∼ − index. Dst Dst 1 GV for ∼ as low as ). For this calculation we use the Inter- ◦ Rc -0.003GV/nT at Marambio. ∼ 5 is , and 360 ◦ Dst values, getting , 315 ◦ with Dst Rc , 270 =0, -100, -200, -300 and -400nT). We note the shift in longitude ◦ 2 RE, where the configuration of the geomagnetic field is strongly Dst ∼ ( , 225 ◦ Dst index as the proxy and considering the Tsyganenko 2001 (TSY01) model , 180 ◦ Dst we show the asymptotic directions of particles with vertical incidence and rigidi- , 135 ◦ 4 , 90 ◦ Asymptotic directions for vertical incidence, covering different levels of geomagnetic activity. However, during periods of geomagnetic storms, the non-dipolar component of Bgeo (pro- Numerical simulations of cosmic particle cascades in the terrestrial atmosphere require a de- duced mainly by magnetospheric electricparticles. currents) can We significantly develope affect simulationsconditions the using to trajectory the compute of asymptotic these directions[13]. for In figure different geomagnetic national Geomagnetic Reference Fieldshows (IGRF10) these for asymptotic modeling directions for the rigiditiesthe Earth 3.1, particle 4.6, magnetic rigidity 10, field. decreases, 20, the 50 asymptotic and Figure a 100 trajectories detailed GV. get analysis We can closer of see to the that the simulationsdeflected as equatorial done at region. it heights lower is From than possible todominated conclude by that a these dipolar particles component. are mostly shows the rigidity cutoff for different tailed knowledge of the pressure height profilecode) in need the specific site. information Some about numerical the modelsTRAN height (e.g. models profiles CORSIKA of are the commonly simulated used site. in Ten CORSIKA different simulations. MOD- ties for different values of for these asymptotic directions, to eastward for higher geomagnetic activity. The inset of 4. Study of the Atmosphere at Marambio The inset shows the rigidity cutoff for different geomagnetic conditions, according to the values (45 We find that the rate of variation of Figure 4: WCDs of LAGO in Antarctic Peninsula PoS(ICRC2015)105 10% for the ’Stan- ∼ . In particular, we compare our 5 10 km) and make significantly overestimations at 6 ∼ A comparison of atmospheric density models from MODTRAN with the observed with baloons Presently, a typical CORSIKA shower simulation at the LAGO Marambio site can be done A comparison between the characterization that we obtain and the ones frequently used in results with three pre-defined atmospheric’Sub-Artic (MODTRAN) Summer’, models and of c) CORSIKA: ’Sub-Artic a) Winter’.ferent ’Standard’, We seasons. make b) the comparisons We using findfrom appropriate the that dif- local the profile profile observed (betweenthe for 10% deviation the of and ’Sub-Artic 40% the for density Winter’ altitudes profilesto model larger from the deviates than the ones significantly 25km). ’Standard’ observed and However, withdifferences ’Sub-Artic the can Summer’ baloons affect models, a of respect proper SMN simulation. atdard’ In Marambio, and particular is it even not differs less in solarger (less less high. differences than than correspond However, that to the larger 5%) found the altitudes. for observations And at the lower in ’Sub-Artic altitudes general (lower Summer’ the than model. models lightly underestimate We notice that the assuming one of the available atmosphericdepiction MODTRAN for models. the In profile order to atat accomplish this 12 a site, UTC detailed in by this thefrom section argentine 1998 we National until analyze 2014, Weather Service at balloonpressure (Servicio Marambio. soundings and temperature Meteorológico data We profiles Nacional, computed measured observed from the SMN) thetypical density soundings atmospheric height as follows: composition, profile we their based take molecular on intofor account masses the ideal the and height gases. the Dalton Thus, lawdensity from for height the profile. partial pressure pressures and temperature data for each altitude, wesimulations compute performed the with CORSIKA, is presented in Figure Figure 5: at Marambio base. Thesubartic atmospheric summer, and MODTRAN c) models the subartic compared winter. here are: a) the standard one, b) the WCDs of LAGO in Antarctic Peninsula PoS(ICRC2015)105 7 1 TeV, e.g., neutron monitors, muon telescopes and ∼ 1GeV up to ∼ 15 km, where details of the shower simulations are crucial. The presented ∼ In this work we presented the project of the LAGO collaboration for installing WCDs in the It is a unique moment for making combined studies of astroparticles flows, combining onboard While neutron monitors are proportional counters that measure the total number of particles The new site of LAGO in Antartic will be ableThese to combined observe studies two particular are classes complementary of and physical will make it possible to achieve a deeper This work was partially supported by the Argentinean grants PICT-2013-1462 (FONCyT- WCDs of LAGO in Antarctic Peninsula altitudes higher than results can help to takefor the decision Marambio, of based what on pre-setsimulation local model for observations. to cosmic use, rays So but showers also at that, the to they atmosphere construct will at a Marambio. improve new the one quality of5. numerical Summary and Conclusions argentine Antarctica. We also presented sometation studies of for the this acquired site that data.rigidities, will and allow Our also a rigidities results better cutoff quantify interpre- the for asymptotic different typical directions geomagnetic atmospheric of conditions. conditions primaries Wewith for presented for the a this different MODTRAN study site models of commonly usingconclude used baloons that in observations, CORSIKA, the and quantifying ’Sub-Artic relative comparedmonths Summer’ differences. them December, model January We and is February. the The resultsof most we showers appropriated found here numerical one will simulations at improve theLAGO we Marambio collaboration, development plan for getting a the to better do simulation ofto in these develope secondary showers the simulations showers. near using In new future particular, we models in plan based the on these Antarctic balloon node observations. spacecraft of detectors (for the nucleons with energies between ae.g., few tens instruments of keV aboard to 100 the MeV(covering ACE, per nucleon, energies SOHO from and SAMPEX probes) with ground particle detectors (without energy discrimination), theto modern measure WCDs the histogram that ofsingle will the geographic be energy localization. installed deposited by These atof the histograms Antarctic the secondary can are primary particles be cosmic able observing re-interpreted raysmeasure only in from for at function numerical the a of first simulations, time the and thegalactic energy thus effects cosmic for of rays the instance at passage will the of terrestrial be a environment. possible magnetic to cloud on the energyevents spectrum (Forbush of drecreases and GLEs), which are of major interest in spaceunderstanding weather. of the space environment. They willeffects contribute to of a the better Sun-Earth comprehension of coupling different onenvironment the and cosmic also radiation at levels the at ground different level levels of of Earth. the terrestrial 6. Acknowledges ANPCyT), UBACyT 20020120100220 (UBA), and PIP-11220130100439CO (CONICET).knowledge We ac- SMN for providing baloons data for Marambio, and also to Viviana Lopez for helping WCDs from the LAGO and Auger observatories). PoS(ICRC2015)105 this this , vol. in , vol. 9, this Proc. , vol. 107, p. 1179, Sun and Geosphere , vol. in press, 2015. , vol. 6, p. P01003, 2011. , vol. in press, 2015. Transient effects and disturbed condi- this Proc. JINST this Proc. 8 , vol. 83. 1998. Journal of Geophysical Research (Space Physics) , vol. 771, p. 92, July 2013. , vol. in press, 2015. , vol. in press, 2015. , vol. in press, 2015. this Proc. this Proc. AstroPhysical J. , vol. in press, 2015. , vol. in press, 2015. this Proc. Proc. in water-cherenkov detector in sierra negra, méxico.,” in in peru,” in wcd detectors for space weather research: first results and further developments,” in Proc. trustworthiness with lago data repositories,” in Aug. 2002. Mathematical structure,” press, 2015. ferent conditions for Buenos Airespp. 41–47, and Jan. Marambio, 2014. Argentina,” rectional geomagnetic effects, background fluenceysis,” calculations in and multi-spectral data anal- ray rate in the 2010-2012 period from the LAGO detectors at chacaltaya,” in tions: observations and simple models solar activity modulation of galactic cosmic rays,” Enhancement of Relativistic Solar Protonstions,” on 2005 January 20. I. Spaceship Earth Observa- [1] H. Asorey for the LAGO Collaboration, “LAGO: the latin american giant observatory,” in [2] I. Sidelnik for the LAGO Collaboration, “The sites of the latin[3] americanA. giant Galindo observatory,” and others for the LAGO Collaboration, “Sensitivity of lago and calibration of a [4] L. Otiniano and others for the LAGO Collaboration, “Development of a high altitude lago site [5] S. Vargas and others for the LAGO Collaboration, “LAGO ecuador, implementing a set of [6] H. Asorey and others for the LAGO Collaboration, “Data accessibility, reproducibility and [7] G. Wibberenz, L. R. J.A., M. Potgieter, and J. Bieber, [8] The Pierre Auger Collaboration, “The Pierre Auger Observatory scaler mode for the study[9] of J. W. Bieber, J. Clem, P. Evenson, R. Pyle, A. Sáiz, and D. Ruffolo, “Giant Ground Level WCDs of LAGO in Antarctic Peninsula us to understand its format. Thecontinuous LAGO support. Collaboration thanks the Pierre Auger Collaboration for its References [13] N. A. Tsyganenko, “A model of the near magnetosphere with a dawn-dusk asymmetry 1. [11] J. Masias-Meza and S. Dasso, “Geomagnetic effects on cosmic ray propagation under dif- [12] M. Suarez and others for the LAGO Collaboration, “The LAGO space weather program: Di- [10] C. Sarmiento-Cano and others for the LAGO Collaboration, “Analysis of background cosmic