Ammosov, V V

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29th International Cosmic Ray Conference Pune (2005) 3, 357360The modern concept of the INCA project elementsV.V. Ammosov , G.I. Britvich , A.P. Chubenko, P.A. Chubenko, V.I. Drobzhev,A.D. Erlykin, G.I. Kol’tsov, O.N.Kryakunova, S.V.Kryukov, G.I. Merzon,B.N. Mukashev, K.K. Mukashev, R.A. Mukhamedshin  , V.N. Murashev,M.I. Panasyuk, V.P. Pavlyuchenko, S.A. Petrochenkov, V.A. Ryabov,O.G. Ryazhskaya  , T. Saito	, A.L. Shchepetov, N.M. Sobolevskii  , A.P. Soldatov ,V.M. Sultangazin, I.S. Trostin, V.G. Vasil’chenko , G.T. Zatsepin  , and A.P. Zhukov (a) Institute for High-Energy Physics, Protvino, 142284 Russia(b) Lebedev Physical Institute, Moscow, 119991 Russia(c) Ionosphere Institute, Almaty, Kazakhstan Republic(d) Moscow State Institute of Steel and Alloys, Moscow, 117936 Russia(e) Physical-Technnical Institute,Almaty, Kazakhstan Republic(f) Abai Almaty State University, Almaty, Kazakhstan Republic(g) Institute for Nuclear Research, Moscow, 117312 Russia(h) Skobel’tsyn Institute of Nuclear Physics, Moscow, 119992 Russia(i) Joint Institute for Nuclear Research, Dubna, 141980 Russia(j) Institute for Advanced Studies, 1-29-6 Shinjuku, Tokyo, 162-0022 Japan(k) Institute for Space Research, Almaty, Kazakhstan Republic(l) Institute for Theoretical and Experimental Physics, Moscow, 117259 RussiaPresenter: R.A. Mukhamedshin (muhamed@sci.lebedev.ru), rus-mukhamedshin-R-abs2-og15-posterThe modern concept of elements of a device designed to study the spectrum and composition of the primarycosmic radiation up to energies of  eV and based on new technologies is considered.1. IntroductionThe main goal of the INCA project [1] is the design of a multipurpose spectrometer for fundamental studiesof the primary cosmic radiation (PCR), in part, for measurements of the spectrum and composition of PCRcomponents at ”knee” energies up to  eV. The project employs a new-type device, namely, ionization-neutron calorimeter (INCA), measuring both ionization and neutron signals and exploiting bipolar pixel silicon-based detectors developed in the framework of this project.2. Properties of INCAGeneral Properties. Basic characteristics of the current INCA conception are listed in Tables 1 – 3 and schemat-ically shown in Figs. 1 – 4. A layout of INCA is shown in Fig. 1. The INCA’s exterior consists of two layers(  and  ) separated with a gap (Figs. 1 and 3). The layer  constitutes a 1-cm thick polyethylene layercontaining a 1-mm thick charge detector (CD) divided into ﬀﬂﬁﬃﬀ cm  sections and coated by a 3-mmthick polyethylene film. The layer  is made of 5-cm thick polyethylene; PMTs and phototriodes are comingthrough its openings. ”Helium-2” neutron counters are placed inside this layer. The interior calorimeter has50 levels, each consisting of the alternating lead and polyethylene layers with a thickness of 1 and 29 mm, re-spectively, and the layer of the long (200 cm) plastic scintillator blocks with the thickness 10 mm (see Fig. 2).Each of the scintillation blocks may include the light spectrum shifters (optical fibers or strips). Polyethyleneand lead constitute  78% and 22% of the total weight. This is equivalent respectively to 4.3 and 0.3 in proton358 V.V. Ammosov et al.Table 1. The basic technical and scientic characteristics of the INCA deviceParameter ValueTotal weight 11050 kgTotal dimensions:  ! "ﬁ  # "ﬁ  #  cm $Calorimeter dimensions  #"ﬁ  !"ﬁ  ! cm $Thickness of the polyethylene reflector 5Thickness of the charge detector’s platform 1Gaps between calorimeter, reflector, CD platform 4Number of scintillators ( "ﬁ%&ﬁ  ! cm $ ) 2000Number of photodetectors (PMT, phototriodes) 4000Number of avalanche photodiodes 400Number of silicon detector plates ( ﬀ'ﬁ()  cm  ) 8000Number of ADC channels 16000Number of the neutron- and * -pulse counting channels 525Power consumption 500 WPrimary information volume of registered event 51 kbActive life time of scientific equipment + 3 yearsThickness in proton’s mean free paths for interaction 4.6 ,.-/ 021Thickness in radiation lengths 13 354Device aperture 2.7 6Geometry factor87%9#: m  srinteraction paths, ,)- ;=<?> , or to 4 and 9 3 4 in radiation lengths. Figure 3 shows the INCA’s section in the planetraversing through one of the SNM17 counters. Figure 4 demonstrates a side view of one scintillator block.Scintillators. The plastic scintillation strips are used as position-sensitive detectors of the neutron and ion-ization signals. PMTs, photo-triodes, and avalanche diodes are used as photodetectors. At the ends of the80% of scintillation strips, phototriodes are placed for registering the ionization component in the amplitude-measurement mode. Light-guide fibers passing through scintillators transmit neutron-produced single lightpulses to avalanche diodes, which are used together with PMTs placed at the ends of 20% of strips for neutronregistration in the pulse-counting mode. The use of difference in signal intensity at the ends of scintillator barsmakes it possible to measure the cascade axis coordinates with an accuracy down to @&AB mm that correspondsto an angular resolution of CED . The usage of Cd or Gd admixtures introducing into scintillators or coating ofscintillation detectors makes it possible to increase essentially the efficiency of neutron-capture registration.Table 2. Distribution of the INCA’s power consumptionFunction Voltage, V Power, WStabilised power supply of phototriodes and neutron counters 2000 50Stabilised power supply of the charge detector and avalanche photo-diodes 100 10Power supply of the calorimeter and charge detector registration channels 5 240Control and data acquisition systems – 100Power reserve – 100Total 500The modern concept of the INCA project ... 359Table 3. Primary information content of registered event.System ChannelsnumberContent of dataper channelAdditionalconditionsTotal,KbCalorimeter 8000 12 bit 2 ADC per phototriode 12Charge detector 8000 12 bit 1 ADC per section 12Pulse counting system 525 1 bite 50 bins per channel 26Monitor/control systems – – – 1Total 51Figure 1. Layout of INCA: (1) lead; (2) polyethylene ; (3) plastic scintillators; (4) SNM-17 gas detectors; (5) Helium-2gas detectors; (6) electronics boards; (7) photodetectors; (8) charge detectors. F and G are outward layers.As scintillators detect mainly signals from delayed * -rays produced in neutron captures and passing to rela-tively big distances from the point of their origin, 100 SNM17 200-cm long gas neutron counters destined todetect just neutrons are placed inside the each fifth polyethylene layer at 20 cm intervals.Charge Detectors. The preferable charge detector (CD) version is a double-layer semiconductor one. However,360 V.V. Ammosov et al.Figure 2. a) Section of one calorimeter layer; b) layout of scintillation block with photodetectors and light guides. Notation:1)  8) are the same as in Fig. 1; 9) photo plates; 10) ber with avalanche photo diode; 11) wavelength-shifting light guide;12) layer containing Cd or Gd. Proportions are not fullled.Figure 3. Cross section of scintillation unit and outer partof INCA. Notations are the same as in Figs. 1 and 2.Figure 4. Side view of scintillation unit. Notation: 1) 12) are the same as in Figs. 1 and 2; 13) amplitude-digitalconverter AD7888AR; 14) operational amplier 5442; 15)shifting register (CMOS- based serial-to-parallel code con-verter) 564IR13.instead of microstrip detectors, it is supposed to apply newly-developed detectors exploiting the concept ofbipolar n-p-n transistor pixels. First high-sensitive matrix-structural detector have been developed and tested.Experimental results correspond to our expectations.This work is partially supported by Russian Foundation for Basic Research, project no. 05-02-17599-; andMinistry of Education and Science of Russian Federation, project no. LSS 1782.2003.2.References[1] Aleksandrov K.V. et al., Nucl. Phys. B (Proc. Suppl.) 122 (2003) 427; ibid, 113 (2002) 344; Nucl. Instr.Meth. in Phys. Res. A459 (2001) 135.

The modern concept of the INCA project elements

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