Dorman, L I

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 29th International Cosmic Ray Conference Pune (2005)  2, 469-472  New multi-directional muon telescope and EAS installation on Mt. Hermon (Israel) in combination with NM-IQSY  L.I. Dormana,b, D.S. Applbaumc, L.A. Pustil'nika, A. Sternlieba, I.G. Zukermana and V.G. Yankeb (a) Israel Cosmic Ray and Space Weather Center and Emilio Segre’ Observatory, affiliated to Tel Aviv University,         Technion, and Israel Space Agency; P.O.Box 2217, Qazrin 12900, Israel (b) Cosmic Ray Department, IZMIRAN Russian Academy of Science; Moscow region, Troitsk 142092, Russia (c) Dept. of Astronomy, Columbia University, 1328 Pupin Physics Laboratories, Mail Code 5246, 550 W. 120th St.  New        York, NY 10027 Presenter: Victor G. Yanke (yanke@izmiran.ru), rus-yanke-VG-abs3-sh36-poster  On Mt. Hermon in the Emilio Segre' Observatory of the Israel Cosmic Ray and Space Weather Center, a plastic scintillation multidirectional muon telescope is under construction, with 144 two-coincidence channels in combination with NM-IQSY. We calculate the angle diagrams of telescope sensitivity and coupling functions for many directions at different zenith and azimuthal angles. We give a description of the electronics scheme and registration system. We also discuss possibly using the telescope in combination with the detection of the total neutron component and different neutron multiplicities. The scintillators of the telescope will be used also for continued measurement of electron-photon and muon EAS arriving in vertical and at different inclined directions. We also calculate the expected coupling functions (or response) functions for different types of EAS. We consider also how NM-IQSY will work in combination with EAS installation for measuring of nucleonic component of EAS.    1. Israeli-Italian Emilio Segre’ Observatory on Mt. Hermon: short description   In Figure 1 we show a block scheme of the main components of the Emilio Segre' Observatory (ESO) on Mt. Hermon and their connection with the Central Laboratory of Israel Cosmic Ray and Space Weather Center in Qazrin and with the Internet.   Figure 1. Schematic description of the main components of the Israeli–Italian Emilio Segre' Observatory (ESO) and their connection with the Central Laboratory in Qazrin and with Internet. Also shown multi-directional muon telescope which will work in combination with NM-IQSY and EAS (see Figure 2).    470          L.I. Dorman et al.  2. Muon telescope and EAS installation combined with NM IQSY  Figure 2 depicts the cross-section of Emilio Segre' Observatory and disposition of both sections of NM-IQSY, as well as the multi-directional muon telescope to be installed in combination with NM-IQSY.     Figure 2. Schematic view of the Israeli-Italian Emilio Segre' Observatory (ESO) on Mt. Hermon, showing both sections of NM-IQSY and the multi-directional muon telescope (the lead of NM will be used as a shield for the muon telescope): the top – vertical cross-section; the bottom – view from above. 1 – two 3-counters sections of NM-IQSY; 2 – polyethylene plates; 3 – polyethylene tubes; 4 – neutron counter 10BF3; 5 – lead tubes; 6 – scintillation detector; 7 – photo-multiplayer; 8 – plastic scintillator 50 cm×50 cm×10 cm; 9 –acquisition system; 10 – sensor of humidity inside Observatory; 11 - sensor of air temperature inside Observatory; 12 – the system of continuous electric power supply; 13 – radio-modem; 14 – recording instrument of EFS-1000 (for measurements of atmospheric electric field); 15 – 1-st computer (DOS-system); 16 – 2-nd computer (Windows system); 17 – 3 rd computer for geomagnetic field (Windows system); 18 - recording instrument for registration of the 3 components of geomagnetic field; 19 – control panel of electric power; 20 – UPS.    From Figure 2 it can be seen that multidirectional muon telescope consisted 24 scintillation detectors 50 cm ×  50 cm × 10 cm (12 under NM and 12 above NM, see Figure 3) with 144 double coincidences formed 12 vertical and 132 inclined telescopes at different zenith and azimuthally angles (see Table 1).  Figure 3. Scintillation detector for the semi-underground multi-directional muon telescope in Qazrin (Israel). 1 – box with reflector, 2 – plastic scintillator 50 cm × 50 cm × 10 cm, 3 – photomultiplier.   New multidirectional muon telescope …                        471  Table 1. Channels of multi-directional muon telescope on Mt. Hermon, combined with 3NM-IQSY. No Channel title Azimuth angle, degree Zenith angle, degree Number of telescopes Expected counting rate Statistical error for 1 hour, % 1 VERTICAL (0) 0 12 162000 0.08 2 N1, S1 0, 180 26.6 8 552960 0.13 3 W1, E1 90, 270 26.6 9 622080 0.13 4 NW1, SW1, SE1, NE1 45, 135, 225, 315 35.3 6 240000 0.20 5 N2, S2 0, 180 45.0 4 19999 0.71 6 W2, E2 90, 270 45.0 6 30000 0.58 7 N1W2, S1W2, S1E2, N1E2 63.4, 116.6, 243.4, 296.6 48.2 4 47407 0.46 8 N2W1, S2W1, S2E1, N2E1 26.6, 153.4, 206.6, 333.4 48.2 3 35555 0.53 9 NW2, SW2, SE2, NE2 45, 135, 225, 315 54.7 2 33750 0.54 10 W3, E3 90, 270 56.3 3 11797 0.92 11 N1W3, S1W3, S1E3, N1E3 71.6, 108.4, 251.6, 288.4 57.7 2 6298 1.26 12 N2W3, S2W3, S2E3, N2E3 56.3, 123.7, 236.3, 303.7 60.7 1 1759 2.38 13 TOTAL 144 4094748 0.05  3. Description of EAS array combined with multi-directional muon telescope and neutron monitor on Mt. Hermon   By coincidences in different combinations of upper scintillators, we obtain a counting of EAS (electron-photon component). This array can be considered as local because the distances between detectors are much smaller than the effective radius of EAS on the level of observations. In this case, on the passage of EAS of density ρ (mean number of particles per 1 m2) the probability that not a single particle will pass through detector of effective area σ will be ( )ρσ−exp . The probability of at least one particle crossing through detector will be ( )ρσω −−= exp1 . The particle distribution in EAS may be represented in the form ( ) ( ) eNrur =ρ , where r is the distance from the EAS axes, eN  is the total number of particles in electron-photon component of EAS, and ( )ru  is the function satisfying the normalization condition and has the form: ( ) 120=∫∞rdrruπ ;      ( ) ( )( )≥=≤−= −−.if,ifexp6.21ooorrbrrurrrrarru                                       (1)  Here or  is the effective radius of the shower. Coefficients a and b are determined from the condition of normalizing and of tie-in of the function ( )ru  at the point r = or .  This gives on the basis of Eq. (1): ( )( )[ ] ( )( )[ ] 6.016.0111 04702.06.01112;12781.06.01112 oooo reerbreeera ×=+−=×=+−= −−−− ππ .      (2) Eq. (2) gives for Mt Hermon (altitude 2 km, or = 72 m) a = 1.775×10–3 m–1, b = 0.6119 m0.6.  Let us suppose that the axis of EAS with total number of particles eN  crossed the observation level in some point P and actuated simultaneously any n detectors of array with total m detectors (meaning that through each of these n detectors crossed at least one particle from total number eN in EAS) and not actuated other any m – n detectors. Let the distance from point P to the detector i is ir  (i = 1, 2, … m). In this case the probability to detect this EAS will be   ( ) ( )( ) ( ) ( )( )( ) ( ) ( )( )σσσρσρω enenmmniiniinmnm NrunmNruCCP −−−−≈∏ −∏ −−= +== expexp1expexp1 11 ,  (3)    472          L.I. Dorman et al.  where nmC ( )( ) 1!!! −−= nmnm . In Eq. (3) we take into account that in our case the distances between detectors << or , and therefore we can put for all rri ≈ , where r is the distance from point P to the center of installation. Let us take into account also that soe EN 3.0≈ , where oE  is the energy of primary particle in GeV, and 1.1≈s  at mountain level 3 km, and 2.1≈s  at sea level (so we expect that for Mt Hermon it will be 13.1≈s ). Because P may be elsewhere, the total probability to detect EAS with eN  particles (generated by primary particle with energy oE ) simultaneously by any n detectors of the local installation with total m detectors (in our case m = 12) will be in the unity of time ( ) ( ) ( )( )( ) ( ) ( )( )∫ −−−−≈ ∞0;expexp12,, rdrNrunmNrudNNDCdNrN eneeenmeoenm σσπσω      (4) ( ) ( )( )( )( ) ( ) ( )( )( )( ) ( )( ) )5(,01411.0exp01411.0exp1exp03834.0expexp03834.0exp12,,6.26.06.26.001111∫ −−−−+∫ +−−−−−−××≈∞ −−−−−−oorsoonsoorsooonsooooonmooonmrdrEnmrrErrrdrErrnmrrErrrrdEEDCdErEσσσσπσωwhere ( )eND  and ( )oED  are differential spectrums of EAS, and oE  is in GeV, or  is in m, σ is in m2. The expected counting rate ( )σ,onm rI  (i.e. number of detected EAS per unity of time by any n coincidences from total m detectors with effective area σ each) will be ( ) ( ) ( ) ooonmeoenmonm dErEdNrNrI ∫=∫= ∞∞00,,,,, σωσωσ .                               (6) The coupling functions characterized the sensitivity of installation to detect EAS will be ( ) ( ) ( ) ( ) ( ) ( ).,,,,,;,,,,, σσωσσσωσ onmoonmoonmonmoenmoenm rIrErEWrIrNrNW ==               (7) It is easy to see that these coupling functions are normalized for any oE , σ, n and m: ( ) ( ) 1,,,,00=∫=∫∞∞ooonmeoenm dErEWdNrNW σσ .                                      (8) The differential energy spectrum of primary CR can be represented by (in units m-2sec-1GeV-1sr-1): ( )×≥×××≤××= −−GeVEifEGeVEifEEDooooo 62.3767.24103,108105.3103,102.2                                        (9) The dependence of expected counting rate ( )σ,onm rI  for Mt. Hermon (m = 12, σ = 0.25 m2) from number of coincidences n is shown in Figure 4, and the coupling functions − in Figure 5.            Figure 4. Expected of EAS counting rate per sec for          Figure 5. The coupling functions for  Mt Hermon installation.                                                         Mt Hermon installation 

New multi-directional muon telescope and EAS installation on Mt. Hermon (Israel) in combination with NM-IQSY

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