ESWW-2. Israeli semi-underground great plastic scintillation multidirectional muon telescope (ISRAMUTE) for space weather monitoring and forecasting

Transcription

1 ESWW-2 Israeli semi-udergrud great plastic scitillati multidirectial mu telescpe (ISRAMUTE) fr space weather mitrig ad frecastig L.I. Drma a,b, L.A. Pustil'ik a, A. Sterlieb a, I.G. Zukerma a (a) Israel Csmic Ray ad Space Weather Ceter ad Emili Segre Observatry, affiliated t Tel Aviv Uiversity, Techi, ad Israel Space Agecy; P.O.Bx 2217, Qazri 129, Israel (b) Csmic Ray Departmet, IZMIRAN Russia Academy f Sciece; Mscw regi, Tritsk 14292, Russia Nw i the frame f Israel Csmic Ray ad Space Weather Ceter uder cstructi is semi-udergrud great plastic scitillati multidirectial mu telescpe (ISRAMUTE) with mre tha tw thusad sigle telescpes i vertical ad may iclied directis at differet zeith ad azimuthally agles. By ISRAMUTE will be determied fr each hur the csmic ray distributi fucti ut f the Earth's magetsphere (by usig spectrgraphic methd ad cuplig fuctis), ad estimate the mvig frm the Su CME ad iterplaetary shck wave fr abut 15-2 hurs befre they captured the Earth (i.e. befre the start f big gemagetic strm). The scitillatrs f ISRAMUTE will be used als fr ctiue measurig f electr-pht ad mu EAS arrivig i vertical ad at differet iclied directis. This will expad the spectrum f measured primary csmic rays up t very high eergies. By usig ISRAMUTE i cmplex with ther csmic ray data (available i real time scale frm Iteret) we plae t realize the prgram f ctiue mitrig f space weather ad frecastig dagerus situatis.

2 1. Itrducti The Israel Csmic Ray ad Space Weather Ceter (ICR&SWC) ad Israeli- Italia Emili Segre' Observatry (ESO) were established i 1998, with affiliati t Tel Aviv Uiversity, t the Techi (Israel Istitute f Techlgy, Haifa) ad t the Israel Space Agecy (uder the aegis f the Miistry f Sciece). The mbile CR Neutr Mitr was prepared by the cllabrati f Israeli scietists f ICR&SWC /ESO (headed by Prf. Lev Drma) with Italia scietists f CR Grup f Rma-Tre Uiversity (headed by Prf. Nuzi Iucci) ad f the Csmic Radiati Sectr IFSI/CNR (headed by Dr. Girgi Villresi), ad trasferred i Jue 1998 Mt. Herm (33 18' N, ' E, 2,25 m abve sea level, vertical cut ff rigidity R c = 1.8 GV). The results f measuremets (data take at e miute itervals f CR eutr ttal itesities at tw separate 3NM- 64 sectis, as well as similar e miute data abut the itesities relatig t eutr multiplicities m = 1, 2, 3, 4, 5, 6, 7 ad 8) are stred i the cmputer. Similar e miute data relatig t the atmspheric electric field, wid speed, three cmpets f gemagetic field, air temperature utside, ad humidity ad temperature iside the CR Observatry are als recrded ad archived. Each mth e hur data f ESO are set t the Wrld Data Ceter i Bulder (USA, Clrad) ad t may CR Observatries i the wrld. A autmatic electric pwer supply usig Uiterruptible Pwer Supply (UPS) ad a diesel geeratr guaratees ctiuus pwer fr ESO. There is a direct radi cecti i real time frm ESO Mt. Herm t the Cetral Labratry f ICR&SWC i Qazri, ad t the Iteret. T exted the experimetal basis f ICR&SWC ESO Mt. Herm (see i [1]) ad a great semi-udergrud plastic scitillati multidirectial mu telescpe are w uder cstructi, with mre tha tw thusad tw-cicideces chaels fr vertical ad iclied directis at differet zeith ad azimuthal agles tgether with EAS istallati i a frmer bmb shelter i Qazri, which will be described shrtly belw. 2. Descripti f semi-udergrud multi-directial mu telescpe i Qazri A semi-udergrud multi-directial mu telescpe is presetly uder cstructi i cllabrati with the CR Grup f the Uiversity New Mexic (headed by Prf. H. Ahluwalia). Figure 1 shws the scitillati detectr fr this udergrud mu telescpe. Figure 1. Scitillati detectr fr the semi-udergrud multi-directial mu telescpe i Qazri (Israel). 1 bx with reflectr, 2 plastic scitillatr 5 cm 5 cm 1 cm, 3 phtmultiplier.

3 Figure 2 depicts the plaed udergrud multidirectial mu telescpe that will start t wrk i Qazri i ear future. Figure 2. The dispsiti f the semi-udergrud multidirectial mu telescpe i the i a frmer bmb-shelter i Qazri, Israel (with characteristics partly listed i Table 1). 1- scitillati detectrs (see Figure 1); 2- acquisiti system ad cmputers; 3 cecti ad pwer feeders. Dimesis are give i cm.

4 I Table 1 is give shrt ifrmati ly fr 997 duble-cicidece telescpes frm ttal 241. The cutig rates f duble-cicidece telescpes at the same zeith ad azimuth directi are summarized. Table 1. Chaels f plaed semi-udergrud multi-directial mu telescpe i ICRC/ESO. N. Chael title Azimuth agles, degree Zeit h agle, degre e Number f telescpes i each directi Expected cutig rate per hur Statistical errr fr 1 hur, % 1 Vertical N1, W1, S1, E1, 9, 18, NW1, SW1, SE1, NE1 45, 135, 225, N2, W2, S2, E2, 9, 18, NW2, SW2, SE2, NE2 45, 135, 225, N3, W3, S3, E3, 9, 18, N4, W4, S4, E4, 9, 18, NW3, SW3, SE3, NE3 45, 135, 225, N5, W5, S5, E5, 9, 18, N4W4, S4W4, S4E4, N1E4 45, 135, 225, N6, W6, S6, E6, 9, 18, N5W5, S5W5, S5E5, N5E5 45, 135, 225, Ttal i 45 directis Descripti f EAS array cmbied with semi-udergrud multi-directial mu telescpe i Qazri By cicideces i differet cmbiatis f upper scitillatrs, we btai cutig f EAS (electr-pht cmpet). This array ca be csidered as lcal because the distaces betwee detectrs are much smaller tha the effective radius f EAS the level f bservatis. I this case, passage f EAS f desity ρ (mea umber f particles per 1 m 2 ) the prbability that t a sigle particle will pass thrugh a detectr f effective area σ will be exp ( ρσ). The prbability f at least e particle crssig thrugh a detectr will be ω = 1 exp( ρσ). The particle distributi i EAS may be represeted i the frm ρ r = u r N, where r is the distace frm the EAS axes, ( ) ( ) e N is the ttal umber f particles i electr-pht cmpet f EAS, ad ( r) e satisfyig the rmalizati cditi ad has the frm: π u( r) rdr = 1; ( r) 2 ( r r ) u is the fucti ar exp if r r, u = (1) 2.6 u( r) = br if r r. Here r is the effective radius f the shwer ( r = 55 m fr sea level bservatis, ad r = 8 m fr mutai bservatis the level abut 3 km). Cefficiets a ad b are determied frm the cditi f rmalizig ad f tie-i f the fucti u ( r) at the pit r = r. It gives the basis f Eq. (1):.6. 6 [ π( e( 1 e) + 1.6) ] = r ; b= r [ 2π( e( 1 e) + 1.6) ] =.472 r a = er 2. (2)

5 Eq. (2) gives fr the level f mutai (altitude 3 km, r = 8 m) a = m 1, b =.6518 m.6 ; fr Mt Herm (altitude 2 km, r = 72 m) a = m 1, b =.6119 m.6 ; fr sea level ( r = 55 m) a = m 1, b =.526 m.6 ; Let us suppse that the axis f EAS with ttal umber f particle N e crssed the bservati level i sme pit P ad actuated simultaeusly ay detectrs f array with ttal m detectrs (meaig that thrugh each f these detectrs crssed at least e particle frm ttal umber N e i EAS) ad t actuated ther ay m detectrs. Let the distace frm pit P t the detectr i is r i (i = 1, 2, m). I this case the prbability t detect this EAS will be m ωm( P) = Cm ( 1 exp( ρiσ) ) exp( ρiσ) Cm( 1 exp( u( r) ) exp( ( m ) u( r) (3) i= 1 i= + 1 where C m = m!(! ( m )!) 1. I Eq. (3) we take it accut that i ur case the distaces betwee detectrs << r, therefre we ca put fr all r i r, where r is the distace frm pit P t the ceter s f istallati. Let us take it accut als that Ne. 3E, where E is the eergy f primary particle i GeV, ad s 1. 1 at mutai level 3 km, ad s 1. 2 at sea level. Because P may be elsewhere, the ttal prbability t detect EAS with N e particles (geerated by primary particle with eergy E ) simultaeusly by ay detectrs f the lcal istallati with ttal m detectrs will be i the uity f time ω m( Ne, r, σ) dne 2πCm D( Ne) dne ( 1 exp( u( r) ) exp( ( m ) u( r) rdr; (4) ωm( E, r, σ) de 2πCm D( E) de s ( 1 exp(.3834r r exp( r r ) E σ ) exp.3834r r ( m ) exp( r r ) s ( E σ) r rdr+ + r s s ( 1 exp(.1411r r E σ ) exp(.1411r r ( m ) E σ) rdr, (5) where D ( N e ) ad ( E ) m 2. The expected cutig rate ( ) D are differetial spectrums f EAS, ad E is i GeV, r is i m, σ is i I m r,σ (i.e. umber f detected EAS per uity f time by ay cicideces frm ttal m detectrs with effective area σ each) will be I m σ. (6) ( r, ) = ωm( Ne, r, σ) dne = ωm( E, r, σ) de The cuplig fuctis characterized the sesitivity f istallati t detect EAS will be ( N, r, σ) ω ( N, r, σ) I ( r, σ) ; W ( E, r, σ) ω ( E, r, σ) I ( r, σ). W m e = m e m m = m m (7) It is easy t see that these cuplig fuctis are rmalized fr ay W m ( N, r, ) dn = W ( E, r, σ) de = 1 e E, σ, ad m: σ e m. (8)

6 The differetial eergy spectrum f primary CR ca be represeted by (i uits m -2 sec -1 GeV -1 sr -1 ): D ( E ) E, = E, if if 6 E 3 1 GeV 6 E 3 1 GeV (9) The expected depedece f cutig rate i depedece f is shw i Figure 3. The cuplig fuctis fr sea level fr differet at m = 45 are shw i Figure 4. Figure 3. The expected depedece f cutig rate f EAS per sec i depedece f fr the EAS istallati i the bmb-shelter i Qazri.

7 Figure 4. The cuplig fuctis fr sea level fr differet at m = 45 fr the EAS istallati i the bmb-shelter i Qazri. Frm right t left fr frm 2 up t 48. Ackwledgemets: Our great gratitude t Prf. Yuval Ne'ema fr ctiue supprt f the wrk f Israel Csmic Ray ad Space Weather Ceter ad Emili Segre' Observatry. This paper is i the frame f COST-724.