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Curie, 6, Dubna, Moscow region, 141980 Russia,Curie, 6,Moscow region, Dubna, - ation ation of the TUS ground - 00U600 LEDs and on the use of the "Simeiz - LZ4

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ns ns in the UV filter ahead of the photomultiplier, as well as other terrestrial sources based system of light sources for the in the for sources light of system based - Volvach, Andrei Dmitrotsa, Dmitrij Neyachenko Neyachenko Dmitrij Dmitrotsa, Andrei Volvach, the Lomonosov [email protected] stations are presented. Other calibration options are being studied: the use of signals from cosmic from signals of use the studied: being are options calibration Other presented. are stations ray interactio nature. a of different prototypes based on LedEngin a ground a of the possible UV light sources are presently under consideration for this purpose: LEDs laser and stations. The design and fabric The TUS space experiment is aimed to study the energy spectrum and arrival direction of Ultra Cosmic Rays (UHECR) High Energy at E ~ 10 in the atmosphere. The "Lomonosov" satellite, with TUS, was launched at the placollaborationTUSApril The operational. fully and orbit in 16,is now Satellite 2016. 20 July, 2017 20 July, - mail: Copyright owned by the author(s) under the terms of the Creative Commons of the under the by terms owned the Creative Copyright author(s) -

Alexandr Volvach Alexandr Institute of SpaceRomania. Science, Magurele, 35th International Cosmic Ray Conference 10 1  4.0(CC License International Attribution-NonCommercial-NoDerivatives Bexco, Busan, Korea Crimean Astrophysical Observatory RAS, Yalta, Simeiz 298688 Crimea ObservatoryAstrophysical RAS,Crimean Yalta, L. Tkachev M. Lavrova, Gorbunov, N. Grebenyuk, V. Joint InstituteJoliot for Nuclear Research, on behalf Alexandr Alexandr flight in calibration experiment: space TUS The Volvach Alexandr 98688 Crimea ObservatoryAstrophysical RAS,Crimean Yalta E Radu Andrei Aurelian Chiritoi, Gabriel Caramete, Ana E. Popescu,

PoS(ICRC2017)177

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19 alkali cathode cathode alkali

- ortium ortium together 500 km. This will be - or the whole detector or the whole diameter tube and UV glass glass diameter and tube UV f -

2 mm - e same systematics. Besides the , number of pixels 16x16 and light light and 16x16 pixels of number , ○ al system of the TUS detector (Fig.1). There There (Fig.1). detector TUS the of system al

type R1463 PMT with type a 13 R1463 PMT - launched launched to the orbit with altitude 500 km on April 28, 2016. The in north one may be understood. However the EAS signal at the space space the at signal EAS the However understood. be may one north in

mamatsu

s. One pixel FoV is ≈ 0.1 which msr, corresponds to a spatial spot of 5x5

and a focal distance of 1.5 m. The DAQ electronics forms 256 channels with with channels 256 forms electronics DAQ The m. 1.5 of distance focal a and μ

the CR spectrum, composition and arrival directions at E > 7x10 > E at directions arrival and composition spectrum, CR the Figure 1. The TUS detector on board the Lomonosov satellite. Lomonosov the on board TUS detector The 1. Figure 2

t = 0.8 Δ The TUS detector. TUS The Introduction

The EAS UV radiation is collected by the optic the by collected is radiation UV EAS The Important Important advantage of this detector will be a possibility to obtain data from the different The The TUS detector was n area of 2.0 m 2.0 of area n on the Earth surface for the 500 km orbit height and 80x80 km and orbit height 500 km the for on the surface Earth Earth Earth atmosphere from the orbital space platform at altitudes 400 2. 1.

window. A PMT quantum efficiency is ~20% for the wavelength 350 nm. The multi The nm. 350 wavelength the for ~20% is efficiency quantum PMT A window. was chosen for operation in linear regime in a wider range of temperatures. The Fresnel mirror a has a time step km are two main parts of this: a ±4.5 (FoV) view of (field [3] modular electronics DAQ corresponding Fresnel mirror and a photo receiver matrix guides). is pixel One a Ha with the based study. With such a data the difference between the results of the Auger detector in the south south the in detector Auger the of results the between difference the data a such With study. based detector TA and hemisphere radiation albedo background to due problem difficult a to leads that weaker times ~100 in is orbit atmosphere. Earth of the beyond beyond the GZK energy limit. The SINP MSU, JINR and Space Regatta Cons preparation. TUS detector the in collaborate Universities Mexican and Korean with several directions of the sky ground with compared as orbit with space at research EAS the the at stable more is conditions same atmospheric apparatus and with th TUS project task is experimental study of UHECR. The fluorescent and Cherenkov radiation of of side night the at detected be will particles UHECR by generated (EAS) Showers Air Extensive the measure to possible The TUS space experiment: calibration in flight PoS(ICRC2017)177

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- TUS TUS

○ Volvach consider consider . А

ground ground level and ght beam with the the with beam ght

60 kg 30%

65 W 65 Value 1.5 m 2.0 m < ±4,5 degree 200 Mbyte/day 10 mrad (5.5 × 5.5 km) (5.5 × 10 mrad

256 (16 clusters of 16 PMTs) of 16 clusters 256 (16 400 nm spectral interval. The light beam is synchronized orbit one week before and after after and before week one orbit synchronized - -

around of the beam axis and may be measered at the the at measered be may and axis beam the of around

hardware and software on the satellite, the regular data data regular the satellite, the on software and hardware

photons/μs photons/μs and the 300

FOV Mass irror area irror 15 Pixel size Pixel Parameter Duty cycle Duty M Focal distance Focal Data (maximum) Data Number of pixels Number Power (maximum) Power a calibration. The experimental technique and the measurement procedure are

ight source during of one calibration run. As it was mention above needs it 100 As above it mention was run. of one calibration ight during source . Essential part of the PMT pixels may be irradiated and calibrated in sush case. in calibrated and be irradiated may pixels PMT of the part . Essential μs) at the orbit altitude for calibration TUS photo detector. Therefore calibration with with calibration Therefore detector. photo TUS calibration for altitude orbit the at μs) 2 Calibration technique Calibration

3.1 Calibration with the powerful LED or laser light beam. light laser or LED the powerful with 3.1 Calibration

Privilege Privilege of this approach is a possibility to illuminate and calibrate more PMT pixels due The The current TUS detector and electronics parameters may be measured and corrected on

TUS of tuning a and tests flight After TUS. of parameters Technical 1. Table The first months of the TUS operation in orbit were dedicated to the apparatus functionality functionality apparatus the to dedicated were orbit in operation TUS the of months first The 3. e got ~7000 triggers/month. After removing the not moonless files the remaining data were quantitatively the awaiting light flux at the space orbit. space the at light flux the awaiting quantitatively tol extended photons/(m Reyleith scattering photons demands much more powerful light beam. Let's directed at some angle to the horizon and simulate EAS due to Reyleith scattering photons in air. air. in photons scattering Reyleith due to EAS and simulate horizon the to angle some at directed isotropically propagate are photons Reyleith There is ~ electronics. and trigger ~ 500 altitude km TUSPMTs with the detector for calibration at ±4.5 source and the calibration TUS between contact optical the for interval 10 sec time angular FOV line line with such TUS the for develop to supposed is technique different Two purpose. this for presently developing li laser or LED powerful the form to is one first The calibration. detector photo pulse light intensity >10 on program. Display the Event through analyzed are received since end of August 2016. Due to solar to Due 2016. August of end since received are that means It orbit. TUS the of part night the during sky the in Moon no is there time moonless of measurements. measurements. During regular operation, the detector measures the UV back of changed conditions under their saturation to avoid of the and PMTs sensitivity adjusts the HV radiation. of background intensity The TUS space experiment: calibration in flight PoS(ICRC2017)177

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range, it is required to introduce a third a introduce to required is it range, g.3): g.3): - ggest ggest ADC counts. Colors denote different pixels. Bottom: snapshot of like like event registered on October 25, 2016. of Top: Waveforms ten PMTs - like event registered on October 25, 2016 are presented in Fig.2. presented are 2016 25, on October registered event like - At the first stage of the transmitter transformation, it is necessary to make changes to the UV necessary the provide To 1). Figure 2. Track

Track optical scheme of the laser emitter (Fi emitter laser of the scheme optical (355 nm). crystals SHG two combining by be obtained can it circuit, radiator the into (THG) that that demonstrated the bi counts. ADC of maximum moment the at plane focal the The TUS space experiment: calibration in flight PoS(ICRC2017)177

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Figure Figure 4. "Portra The design and fabrication of the TUS ground photode of the image 3. Schematic Figure

2). The optics of the range finder telescope should be adapted satellite over the Crimea. over satellite based on LedEngin (Fig.4). presented compression compression of the pulse, the SBS is included in the nm. circuit; of 532 a wavelength at radiation provides SHG + 3, and Nd it YAG is on cascades amplification a compressor, MF, and two The TUS space experiment: calibration in flight PoS(ICRC2017)177

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ata, including the TUS measurements of EAS. EAS. of TUS measurements the including ata, em em and trigger electronics characteristics were taken in

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5 years of operation in space the TUS exposure will be 12000 be will exposure TUS the space in operation of years 5 - [7]:

- Angular divergence of light beam ±4.5 beam light of divergence Angular

3.2 Calibration with the point LED beam LED the point with 3.2 Calibration

2. The ground 3 During 1. The TUS mission aboard the dedicated Lomonosov sa the dedicated Lomonosov TUS aboard mission The 1. 3.3 Prototype presently is calibration reciever photo TUS the for sourse prototype a fabrication and Design 6. Intensity of light flux at the 500 km latitude 100 500 km the at flux light of 6. Intensity session ofcalibration the time 7. Duration 1 source light of stability term 8. Long The source has to provide 100 1. Light pulse duration duration pulse 1. Light energy pulse The 2. interval spectral The 3. frequency pulse The 4. 5. Calibration Calibration source parameters were evaluated based on the Monte In the second technique the LED beam is directed vertically and can be measured by the Other calibration options Otherare options being calibration studied: the use of signals from cosmic beams are currently under development. under are currently beams comparable with the exposure of the largest ground orbit. in calibration receiver photo TUS for preparation in are sources thi for consideration under presently are sources light UV orbital orbital UV telescope for The is innow satellite 28, 500 April solarthe 2016. km the launched satellite on was "Lomonosov" study of EASs d takes produced and operates orbit, synchronized by UHECR. The multifunctional company [8].company It is a high e well is distribution power spectral The lens. glass integrated and 7.0mm x 7.0mm size small 11W, purposes. TUS calibration the for suitable 4. Conclusion fluctuations of the photon absorbtion on the way from the ground source and the detector in orbit. in detector the and source ground the from way the on absorbtion photon the of fluctuations under One way. research to use powerful LZ4 techniques techniques the difficult and unclear presently problem is an adequate consideration of the account [4] account TUS photo detector if the calibration source is inside of ±4.5 source image on photo detecor matrix may cross up to and 16 calibrated PMTs them during the above. flight satellite TUS detector where the optical syst in the UV filter ahead of the photomultiplier, as well as other te nature. The TUS space experiment: calibration in flight PoS(ICRC2017)177

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05498.

02 - 00U600.pdf -

13065 and No. 15 - 29 - 6 ICRC Proc.Merida (2007). Vol.5, 0162.p.881, ID ICRC Proc.MeridaVol.5, (2007).

The TUS experiment on board the “Lomonosov” satellite was realized within the Federal http://www.ledengin.com/les/products/LZ4/LZ4 L. Tkatchev et al., 30th L. Tkachenko272. ID et al.,A. 32d (2011) Proc. ICRC Beijing 11 G. Garipov et al., Part.Phys. Nuclei 10(1) Lett. (2013) 49. Tkachenko et all.,A. 33d Proc. ICRC Rio De Janeiro(2013) ID 0423. B. A. Khrenov et A. al., Nucl. B Phys. (2002) (Proc.115. Suppl.)B. 112 2058.Nucl. (2004) 67(11) Atom. Khrenov et A. al., Phys. B. Abrashkin et al., Advances in Space 37Research Abrashkin et (2006)al., 1867.

[8] [4] [5] [6] [7] [1] [2] [3] Space Program of Russia with funding by the 1 No. grants RFBR by supported Russian Space Agency. The data analysis is References The TUS space experiment: calibration in flight Acknowledgments PoS(ICRC2017)177

, , , a c

b;d

Volvach

, . b

Grebenyuk 746 Korea , P.A. Klimov - e , A.E. PuchkovA.E. , f

, V.M. a , M. Kim a , TkachenkoA.V. , E. Ponce a a ro 2066,Suwon,440 - , G.K. Garipov a , B.A. Khrenov , PetrovV.L. a e

, A.V. ,Shirokov A.V. a a V.E. Eremeev

, I.H. Park , 8 a g 1, Gory,Leninskie Moscow,119991, Russia -

, M.Yu. Zotov , S.A. Sharakin a c Curie, 6, Dubna, Moscow region,Russia, 141980 - , Kaznacheeva M.A. a yunkwan University, Seobu Joliot kovsky , M.I. Panasyuk f , I. A. Dmitrotsa c I.V. Yashin , g , A.N. Sen c , N.N. Kalmykov e , O. Martinez f , A.A. ,Botvinko A.A. UHECR/TLE collaboration b - , E. VolvachA. , J. Lee , S. Jeong b b;d b , O.A. ,Saprykin O.A. f Crimea Astrophysical Observatory RAS, Simeiz,Crimea Russia g Joint Institute for Nuclear Research, StateDubna University, University str., 19, Bld.1, Dubna, Moscow region, Russia Space Regatta Consortium, ul. 4a,Lenina, 141070 Korolev, Moscow region,Russia Department of Physics and ISTS, Sungk M.V. Lomonosov Moscow State University, GSP Benemerita Universidad Autonoma de Puebla, 4 104 sur Historico Centro C.P.72000,Puebla, Mexico

c d e f A.A. GrinyukA.A. M.V. Lavrova H. Salazar TkachevL.G. a b The TUS space experiment: calibration in flight LomonosovThe S.V. Biktemerova