The CERN Neutrino to Gran Sasso (CNGS) project aims to produce a high energy,
wide band $\nu_{\mu}$ beam at CERN and send it toward the INFN Gran Sasso
National Laboratory (LNGS), 732 km away. Its main goal is the observation of
the $\nu_{\tau}$ appearance, through neutrino flavour oscillation. The beam
started its operation in August 2006 for about 12 days: a total amount of
$7.6~10^{17}$ protons were delivered to the target. The LVD detector, installed
in hall A of the LNGS and mainly dedicated to the study of supernova neutrinos,
was fully operating during the whole CNGS running time. A total number of 569
events were detected in coincidence with the beam spill time. This is in good
agreement with the expected number of events from Montecarlo simulations.Comment: Accepted for publication by the European Physical Journal C ; 7
  pages, 11 figure

Agafonova, N. Yu.

Aglietta, M.

Antonioli, P.

Bari, G.

Bonardi, A.

Boyarkin, V. V.

Bruno, G.

Fulgione, W.

Galeotti, P.

Garbini, M.

Ghia, P. L.

Giusti, P.

Kemp, E.

Kuznetsov, V. A.

Kuznetsov, V. V.

Malguin, A. S.

Menghetti, H.

Persiani, R.

Pesci, A.

Pless, I. A.

Porta, A.

Ryasny, V. G.

Ryazhskaya, O. G.

Saavedra, O.

Sartorelli, G.

Selvi, M.

Vigorito, C.

Votano, L.

Yakushev, V. F.

Zatsepin, G. T.

Zichichi, A.

English

arXiv

The CERN Neutrino to Gran Sasso (CNGS) project aims to produce a high energy, wide band $\nu_{\mu}$ beam at CERN and send it toward the INFN Gran Sasso National Laboratory (LNGS), 732 km away. Its main goal is the observation of the $\nu_{\tau}$ appearance, through neutrino flavour oscillation. The beam started its operation in August 2006 for about 12 days: a total amount of $7.6~10^{17}$ protons were delivered to the target. The LVD detector, installed in hall A of the LNGS and mainly dedicated to the study of supernova neutrinos, was fully operating during the whole CNGS running time. A total number of 569 events were detected in coincidence with the beam spill time. This is in good agreement with the expected number of events from Montecarlo simulations.The CERN Neutrino to Gran Sasso (CNGS) project aims to produce a high energy, wide band $\nu_{\mu}$ beam at CERN and send it toward the INFN Gran Sasso National Laboratory (LNGS), 732 km away. Its main goal is the observation of the $\nu_{\tau}$ appearance, through neutrino flavour oscillation. The beam started its operation in August 2006 for about 12 days: a total amount of $7.6~10^{17}$ protons were delivered to the target. The LVD detector, installed in hall A of the LNGS and mainly dedicated to the study of supernova neutrinos, was fully operating during the whole CNGS running time. A total number of 569 events were detected in coincidence with the beam spill time. This is in good agreement with the expected number of events from Montecarlo simulations

Agafonova, N.Yu.

Boyarkin, V.V.

Ghia, P.L.

Kuznetsov, V.V.

Kuznetsov, V.A.

Malguin, A.S.

Pless, I.A.

Ryasny, V.G.

Ryazhskaya, O.G.

Saavedra, Oscar

Selvi, Marco

Yakushev, V.F.

Zatsepin, G.T.

CERN Document Server

arXiv:0710.1536v1  [hep-ex]  8 Oct 2007EP J m anuscript N o.(willbe inserted by the editor)FirstCN GS events detected by LVDN.Yu.Agafonova1,M .Aglietta2,P.Antonioli3,G .Bari3,A.Bonardi2,V.V.Boyarkin1,G .Bruno2;4,W .Fulgione2,P.G aleotti2,M .G arbini3;5,P.L.G hia2;4,P.G iusti3,E.K em p6,V.V.K uznetsov1,V.A.K uznetsov1,A.S.M alguin1,H.M enghetti3,R.Persiani3,A.Pesci3,I.A.Pless7,A.Porta2,V.G .Ryasny1,O .G .Ryazhskaya1,O .Saavedra2,G .Sartorelli3,M .Selvi3a,C.Vigorito2,L.Votano8,V.F.Yakushev1,G .T.Zatsepin1,A.Zichichi3.1Institute forNuclearResearch,Russian Academ y ofSciences,M oscow,Russia2 Institute ofPhysicsofInterplanetary Space,INAF,Torino,University ofTorino and INFN-Torino,Italy3 University ofBologna and INFN-Bologna,Italy4INFN-LNG S,Assergi,Italy5M useo Storico della Fisica,Centro Studie Ricerche "E.Ferm i",Rom e,Italy6University ofCam pinas,Cam pinas,Brazil7M assachusettsInstitute ofTechnology,Cam bridge,USA8 INFN-LNF,Frascati,ItalyReceived:date / Revised version:dateAbstract. The CERN Neutrino to G ran Sasso (CNG S)projectaim sto produce a high energy,wide band beam atCERN and send ittoward the INFN G ran Sasso NationalLaboratory (LNG S),732 km away.Its m ain goalis the observation of the  appearance,through neutrino avour oscillation.The beamstarted itsoperation in August2006 forabout12 days:a totalam ountof7:6 1017protonswere deliveredto the target.The LVD detector,installed in hallA ofthe LNG S and m ainly dedicated to the study ofsupernova neutrinos,was fully operating during the whole CNG S running tim e.A totalnum ber of569eventsweredetected in coincidencewith thebeam spilltim e.Thisisin good agreem entwith theexpectednum berofeventsfrom M ontecarlo sim ulations.PACS. 14.60.Pq Neutrino m ass and m ixing { 29.27.Fh Beam characteristics { 29.40.M c Scintillationdetectors{ 95.55.Vj Neutrino,m uon,pion,and otherelem entary particle detectors;cosm ic ray detectors1 IntroductionTheCERN NeutrinostoG ran Sasso(CNG S)projectaim sto produce a high energy,wide band  beam atCERNand send ittoward the INFN G ran Sasso NationalLabo-ratory (LNG S).Itsm ain goalistheobservation ofthe appearance,through neutrino  avour oscillation,by theO pera experim ent.TheLVD detector,installed in theHallA oftheLNG S,ism ainly dedicated to the observation ofsupernova neu-trinos.As proven in [1],due to its large area and activem ass,LVD can actasa very usefulbeam m onitor,detect-ingtheinteraction ofneutrinosinsidethedetectorand them uonsgenerated bythe interaction in therockupstreamthe detector.TheCNG S beam started itsoperation in August2006,afterthreecom m issioning weeks.LVD wasfully operativeduring the whole rstrun ofthe CNG S beam .In this work we present the results ofthe events de-tected in coincidence with the beam spilltim e and showsom ecom parisonswith the M ontecarlo sim ulation.aCorresponding author:selvi@ bo.infn.it2 The CN GS beamThe inform ations about the CNG S beam characteristicsaretakenbytheLHCLO G CNG S O PERA database(here-after DB) [2].Two m ain quantities are relevantfor eachproton extraction:{ the UTC tim e ofthe spill(in ns),{ the num berofextracted protonson target(p.o.t.) 1.The CNG S beam started its rstrun ofoperation on18th August,2006 ( rst spillat 11:31:54.072 UTC) and nished on 30th August(lastspillat03:30:04.872 UTC).In the following we willrefer to this  rst run as Run1.Thetotalnum berofprotonsdeliveredagainstthegraphitetarget is 7:59 1017.The beam intensity per each spillisshown in  gure1.Itstarted with an average intensity of1:381013 p.o.t.perspilluntil23rd August;then therewasa prede ned stop called \M achine Developm ent" (M D).1D ue to som e known problem s (see [3]) it happened thatforsom e extraction there was only the UTC tim e oronly thenum berofp.o.t..In the following we willconsideronly thoseextraction where both the inform ationswere present.2 LVD collaboration:FirstCNG S eventsdetected by LVDO n 25th August the run restarted with a slightly higherintensity of1:64 1013 p.o.t.perspill,on average.The tim e structure ofthe CNG S beam is character-ized by two extractions,10:5 slong,separated by 50 m s;thispattern isrepeated each CNG S cycle,whosedurationcan change:during Run1 there were two m ain repetitioncycles:16:8 sand 22:8 s.Fig.1.Beam intensity (in protonson target)pereach spillofRun1.3 The LVD detectorLVD is a large volum e liquid scintillator detector dedi-cated to the study ofcore collapse supernova neutrinos.Theactivescintillatorm assisabout1000t,whiletheironand stainless steelsupport structure is  900 t.It hasa m odular structure,m ade of840 identicalscintillationcounters.Each counterisviewed on thetop by threepho-tom ultipliertubes.Thecountersaregrouped in threebigm odules,called \towers",with independentdata acquisi-tion.The energy calibration ofthe scintillation countersisdone each m onth through the (known)energy releasedby cosm ic m uons.The highestdetectable energy in eachcounterisbetween 200 and 400 M eV.The front area ofthe whole detector (orthogonaltotheCNG S beam )is 12 10m 2,see gure2.A detaileddescription ofthedetectorand itsperform ancesisin [7].During Run1 LVD was fully operative with 100% ofuptim e(de ned asthefraction oftim ewhereLVD isableto detectan event)and an averageactivem assof950 t.Fig.2.Frontview ofthe LVD detector.4 M C sim ulation ofthe expected eventsThe CNG S events in LVD can be subdivided into twom ain categories:{  charged current(CC) interactionsin the rock up-stream theLNG S;they produceam uon thatcan reachLVD and be detected,{  CC and neutralcurrent (NC) interactions in them aterial(liquid scintillator and iron of the supportstructure)ofLVD.W e developed a full M ontecarlo sim ulation that in-cludesthegeneration oftheneutrinointeraction products,the propagation ofthe m uon in the G ran Sasso rock andtheresponseoftheLVD detector.Thedetailsofthesim u-lation weredescribed in [1];however,with respectto thatpaper,som em odi cationsweredonewith up{to{datein-form ations.In particularwe now use the CNG S  ux cal-culated in 2005 by the Fluka group [4]and the neutrinocrosssection NUX-FLUK A [5].Therearealso som em od-i cationsin thedetector:thereareactually 7 activelevelsofscintillation counters instead ofthe 8 previously con-sidered,and the energy threshold for the de nition ofaCNG S eventisnow 100 M eV instead of200 M eV.Theresulting num berofexpected events,atthenom -inalintensity 4:5 1019 p.o.t./y is 32160/y,equivalent to7:147 10 16 events per p.o.t. (considering 200 e ectivedaysperyear,itcorrespondsto  160 CNG S eventsperday):78% arem uonsfrom the rock,17% areCC interac-tionsin the detectorand 5% areNC.During Run1 thetotalnum berofp.o.t.was7:59 1017,thus542 eventsareexpected in LVD.LVD collaboration:FirstCNG S eventsdetected by LVD 35 CN GS detected eventsThe LVD events are  ltered using a very loose selectioncut:we require to have at least one scintillation counterwith an energy releaselargerthat100M eV.Theresultingrate isquite stable,with an averagevalue of0:37 Hz,see gure3.Fig.3.Background rate ofeventsduring Run1.These eventspresentatleastonescintillation counterwith an energy releaselargerthan 100 M eV.Am ong thissam plethe  rstselection criteria isbasedon the coincidence ofthe LVD eventtim e with the beamspilltim e written in the DB.Two m ain correctionshavebeen done:the neutrino tim e of ight from Cern to theLNG S (2:440 m s) and the propagation ofthe G PS tim esignalfrom the outside laboratoriesto slaveclocksin theunderground hall(42116,42064and 42041nsrespectivelyfortower1,2and 3),m easured in July,2006togetherwiththe otherexperim entsatLNG S [6].During Run1 there were som e additionaltim e shiftsbetween theLNG S tim eand theUTC tim ewritten in theDB:from the beginning until18th 16:00 itwas+ 100 s,then + 10 s until22nd 9:00 and   2 m s until23rd 5:30.Afterthe M D there wasno additionalbias.Afterapplying allthese corrections,we search fortheCNG S events in the interval[  15;+ 25]s around thestart tim e ofthe beam spill.In this way 569 events areselected;theirdistribution in thetim ewindow isshown in gure4.Thefoureventswith tim edi erencebetween   13 and  8 soccured on 19th Augustwhen therewasa failureintheLNG S m asterclock.Thesecond m asterwasswitchedon and atim eshiftofabout10swaspresent.Thusthoseeventsareconsidered in the analysis.Fig. 4. D istribution ofthe detection tim e ofthe 569 CNG Sevents,with respectto the initialtim e ofthe beam spill.In  gure5 (left)weshow thecom parison between theexpected and detected event rate per each day ofdataacquisition;in  gure5 (right)thecom parison oftheinte-gralnum berofevents,hourby hour,isshown.G iven thepresently lim ited statistics,theagreem entisrathergood.Two exam ples of typical CNG S events in LVD areshown in  gure6 (m uon from the rock)and 7 (neutrinointeraction inside the detector).5.1 Com parison with the M C sim ulationIn the following we show the com parison between theCNG S detected eventsand the resultsofourM C sim ula-tion,norm alized to the sam e num berofevents.In  gure8 we show the distribution ofthe num berofscintillationcountershit per each event,with an energy threshold of10 M eV,norm alized to the totalsam ple of569 detectedevents;giventheavailablestatisticstheagreem entisgood.In ordertoselecttheeventsgenerated in therock,pro-ducingapenetratingm uon insidethedetector,weperformthem uon track reconstruction with a linear tto thecen-tersofthe hitscintillation counters.Requiring atleast3hitcountersand a good 2 (probability largerthan 1% inboth theTOP and SIDE projections)weselect319events.From the M C sim ulation we estim ate that,using thisse-lection cut,thee ciency todetect\m uonsfrom therock"isabout80% and the contam ination of\internalevents"islow (lessthan 5% ).In  gure9 thetotalam ountofenergy detected by thescintillation countersin \m uonic" eventsisdisplayed.Forthisselected sam ple ofeventswe can reconstructthe m uon direction and com pare itwith the expectation4 LVD collaboration:FirstCNG S eventsdetected by LVDFig.5.Com parison between the expected and detected num berofeventsduring Run1.In the leftpanelthere is the num berofeventsperday:observed (black circles)and expected (blue line).In the rightone the integrated num berofevents:observed(black solid line)and expected (blue dashed line).from the reconstruction of M C events. The results areshown fortheanglebetween the m uon and the m ain axisofthe hallA:itsprojectionsin the SIDE and TOP viewofthe detectorarein  gure10 and 11 respectively.The events are alm ost horizontaland the m ain partofthem are reconstructed exactely at 0 because ofthediscretenessofthescintillation counters(crosssection 1 1m 2).In the TOP view the beam isparallelto the hallAaxis,while in the SIDE view the beam \com esout" fromthe  oorwith an angle of3:2,asseen in  gure10.Theagreem entofthedataand theM C sim ulation isvery goodin both the projections.5.2 BackgroundThebackgroundisestim ated consideringtherateofeventsshownin gure3am ongwhichtheCNG S eventsaresearchedfor,with an averagevalueof0:37 Hz.W erem ind thatthetim e window where we search for the events around thebeam spilltim e is 40 s wide,and the num ber ofusefulspillsin the DB is51581.Thusthe num berofeventsdueto the background,during Run1,isN bkg = 0:37 H z 40 s 51581= 0:764practically negligible.6 ConclusionsW epresented theresultsofthe rsteventsdetected by theLVD detector in coincidence with the CNG S beam .The rstrun ofthe CNG S beam wasstarted in August2006,with an overallnum ber of7:6 1017 protons delivered tothe target.The LVD detectorwasfully operative duringthe wholerun,with an averageactivem assof950 t.LVD can detectthe CNG S neutrinosthrough the ob-servation ofpenetrating m uons originated by  CC in-teractions in the rock upstream the LNG S and throughinternalCC and NC neutrino interactions.The expected num ber ofevents,as predicted by ourM ontecarlosim ulation,is542.W esearched fortheCNG Seventsby looking atthe tim e coincidence with the beamspilltim e;the num berofdetected eventsis569.Thereisagoodagreem ent,betweenthedetected eventsand theM C sim ulation,in thedistribution ofthenum berofhitcounters,thetotalenergy released in theapparatusand the direction ofthe reconstructed m uons.W eestim atethatthenum berofeventsduetotheback-ground islowerthan one in the whole Run1 tim e.Thus,this rstrun oftheCNG S beam con rm ed that,as it was proposed in [1],LVD can act as a very usefulCNG S beam m onitor.AlsotheO peracollaborationreportedabouttheirm ea-surem ents[8]:they detect319 eventsagainsta predictionof300,obtaining results very sim ilar to ours.A detaileddiscussion about the com parison ofexpected and detecteventsin LVD ispostponed tothenextCNG S runs(sched-uled in fall2007),when a large num berofeventswillbeavailableand thebeam characteristicswillbebetterundercontrol.LVD collaboration:FirstCNG S eventsdetected by LVD 5Fig.6.D isplay ofa CNG S events:typicalcharged currentinteraction in therock upstream LVD ,producing a m uon thatgoesthrough the detector.The colours represent the am ount ofenergy released in the scintillation counters,sum m ed along eachprojected view;the legenda isexpressed in G eV.The black straightline isthe resultofa lineartto the hitcounters.7 Acknowledgem entsW e thank G .Battistoni,A.Ferrariand P.Sala for pro-viding usthe tablesofthe neutrino cross-sectionsand A.G uglielm iforthedetailsoftheCNG S M C sim ulation.W ealso would liketo thank D.Autiero forhishelp in access-ing the inform ation in the CERN databaseand form anydiscussions aboutthe details ofthe beam characteristicsand statusduring Run1.References1. M .Aglietta etal.,CNG S beam m onitorwith theLVD detec-tor,Nuclear Instrum ents and M ethods in Physics ResearchA 516,(2004)96.2. C. Roderick, LHC LO G G ING - CNG S-O PERA gatewaydatabase userguide,https://edm s.cern.ch/le/750206/1/LHCLO G CNG S O PERA G W D B G UID E.pdf.3. D .Autiero,private com m unication.See also his presenta-tion atthe G ran Sasso sem inar \First eventsfrom CNG S",January 2007, available at http://www.lngs.infn.it in thesem inarweb page.4. A. Ferrari et al., An updated M onte Carlo calcula-tion of the CNG S neutrino beam , CERN-AB-Note-2006-038, ED M S No. 745389. Fluxes available athttp://www.m i.infn.it/ psala/Icarus/cngs.htm l5. G . Battistoni et al., The FLUK A nuclear cascade m odelapplied to neutrino interactions,Proceedings ofNUINT’02,D ecem ber2002,University ofCalifornia,Irvine,USA.Availableonlineathttp://nuint.ps.uci.edu/proceedings/sala.pdf6. D .Autiero et al.,M easurem ent ofthe bre delays for theG PS signalunderground distribution,internalnote,(2006).7. M .Agliettaetal.,Them ostpowerfulscintillatorsupernovaedetector,Nuovo Cim ento A 105,(1992)1793.8. R.Acquafredda etal.[O PERA Collaboration],Firsteventsfrom theCNG S neutrino beam detected in theO PERA exper-im ent,New J.Phys.8,(2006)303;[arXiv:hep-ex/0611023].6 LVD collaboration:FirstCNG S eventsdetected by LVDFig.7.D isplay ofa CNG S events:neutrino interaction insidethe LVD detector.The colours represent the am ount of en-ergy released in the scintillation counters,sum m ed along eachprojected view;the legenda isthe sam e asin gure 6.Fig. 8. D istribution of the num ber of scintillation countershitpereach CNG S event:com parison between thedata (blackcrosses)and M C sim ulation (red line).Fig. 9. D istribution ofthe totalenergy detected in the ap-paratuspereach CNG S eventwhere a m uon isreconstructed:com parison between the data (black crosses)and M C sim ula-tion (red line).LVD collaboration:FirstCNG S eventsdetected by LVD 7Fig. 10. D istribution ofthe \side" projection ofthe angle between the reconstructed m uon track and the m ain axis oftheLNG S hall:com parison between thedata (black crosses)and M C sim ulation (red line).In therightpicturethereisa descriptionofthe considered angle zy.Fig.11.D istribution ofthe\top" projection oftheanglebetween thereconstructed m uon track and them ain axisoftheLNG Shall:com parison between the data (black crosses) and M C sim ulation (red line).In the rightpicture there is a description ofthe considered angle xy.

First CNGS events detected by LVD

Porta, Amanda

HAL: Hyper Article en Ligne

The CERN Neutrino to Gran Sasso (CNGS) project aims to produce a high energy, wide band nu(mu) beam at CERN and send it toward the INFN Gran Sasso National Laboratory (LNGS), 732 km away. Its main goal is the observation of the nu(tau) appearance, through neutrino flavour oscillation. The beam started its operation in August 2006 for about 12 days: a total amount of 7.6 x 10(17) protons were delivered to the target. The LVD detector, installed in hall A of the LNGS and mainly dedicated to the study of supernova neutrinos, was fully operating during the whole CNGS running time. A total number of 569 events were detected in coincidence with the beam spill time. This is in good agreement with the expected number of events from Monte Carlo simulations.52484985

Agafonova, NY

Aglietta, M

Antonioli, P

Bari, G

Bonardi, A

Boyarkin, VV

Bruno, G

Fulgione, W

Galeotti, P

Garbini, M

Ghia, PL

Giusti, P

Kemp, E

Kuznetsov, VV

Kuznetsov, VA

Malguin, AS

Menghetti, H

Persiani, R

Pesci, A

Pless, IA

Porta, A

Ryasny, VG

Ryazhskaya, OG

Saavedra, O

Sartorelli, G

Selvi, M

Vigorito, C

Votano, L

Yakushev, VF

Zatsepin, GT

Zichichi, A

Repositorio da Producao Cientifica e Intelectual da Unicamp

The European Physical Journal C

The CERN Neutrino to Gran Sasso (CNGS) project aims to produce a high energy, wide band $nu_{mu}$ beam at CERN and send it toward the INFN Gran Sasso National Laboratory (LNGS), 732 km away. Its main goal is the observation of the $nu_{tau}$ appearance, through neutrino flavour oscillation. The beam started its operation in August 2006 for about 12 days: a total amount of $7.6~10^{17}$ protons were delivered to the target. The LVD detector, installed in hall A of the LNGS and mainly dedicated to the study of supernova neutrinos, was fully operating during the whole CNGS running time. A total number of 569 events were detected in coincidence with the beam spill time. This is in good agreement with the expected number of events from Montecarlo simulations

N. Y.u. Agafonova

M. Aglietta

P. Antonioli

G. Bari

A. Bonardi

V. V. Boyarkin

G. Bruno

W. Fulgione

P. Galeotti

P. L. Ghia

P. Giusti

E. Kemp

V. V. Kuznetsov

V. A. Kuznetsov

A. S. Malguin

H. Menghetti

A. Pesci

I. A. Pless

A. Porta

V. G. Ryasny

O. G. Ryazhskaya

O. Saavedra

M. Selvi

C. Vigorito

L. Votano

V. F. Yakushev

G. T. Zatsepin

GARBINI, MARCO

PERSIANI, RINO

SARTORELLI, GABRIELLA

ZICHICHI, ANTONINO

Archivio istituzionale della ricerca - Alma Mater Studiorum Università di Bologna

First CNGS events detected by LVD

Abstract

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CERN Document Server

HAL: Hyper Article en Ligne

Repositorio da Producao Cientifica e Intelectual da Unicamp

Archivio istituzionale della ricerca - Alma Mater Studiorum Università di Bologna