1. Tunka-133: results and status L.A.Kuzmichev (MSU SINP) On behalf of the Tunka Collaboration 4.06.2012 23th ECRS, MOSCOW

2. S.F.Beregnev, S.N.Epimakhov, N.N. Kalmykov, N.I.KarpovE.E. Korosteleva, V.A. Kozhin, L.A. Kuzmichev, M.I. Panasyuk, E.G.Popova, V.V. Prosin, A.A. Silaev, A.A. Silaev(ju), A.V. Skurikhin, L.G.Sveshnikova I.V. Yashin, Skobeltsyn Institute of Nucl. Phys. of Moscow State University, Moscow, Russia; N.M. Budnev, O.A. Chvalaev, O.A. Gress, A.V.Dyachok, E.N.Konstantinov, A.V.Korobchebko, R.R. Mirgazov, L.V. Pan’kov, A.L.Pahorukov, Yu.A. Semeney, A.V. Zagorodnikov Institute of Applied Phys. of Irkutsk State University, Irkutsk, Russia; B.K. Lubsandorzhiev, B.A. Shaibonov(ju), N.B. Lubsandorzhiev Institute for Nucl. Res. of Russian Academy of Sciences, Moscow, Russia; V.S. Ptuskin IZMIRAN, Troitsk, Moscow Region, Russia; Ch. Spiering, R. Wischnewski DESY-Zeuthen, Zeuthen, Germany; A.Chiavassa Dip. di Fisica Generale Universita' di Torino and INFN, Torino, Italy. A.Haungs, F. Schroeder Karlsruhe Institute of Technology, Karlsruhe, Germany Tunka Collaboration

3. OUTLINE 1. Tunka-133. 2. Energy spectrum. 2. Mass composition ( V.Prosin report, at next session) 3. Plan for the Tunka-133 upgrading.

4. Tunka-133 – 1 km 2 “dense” EAS Cherenkov light array Energy threshold 10 15 eV Accuracy: core location ~ 10 m energy resolution ~ 15%  X max < 25 g∙cm -2

5. Tunka-133: 19 clusters, 7 detectors in each cluster Optical cable Cluster Electronic box DAQ center PMT EMI 9350 Ø 20 cm 4 channel FADC boards 200 MHz, 12 bit

6. 4 channel FADC Cherenkov light pulses at two detectors of a cluster at the core distance of ~ 700 m 1. ADC AD9430, 12 bit, 200 MHz 2. FPGA XILINX Spartan-3 t (  5 ns)

7. 1 км 2011 To the ultra-high energy! Tunka-133 is extended by 6 distant external clusters

9. Energy reconstruction E = A (Q200) g Density of Cherenkov light at core distance of 200 m For 10 16 – 10 18 eV (CORSIKA): g = 0.94±0.01

10. Absolute energy calibration : The QUEST experiment ( Cherenkov detectors at EAS-TOP) P – steepness of LDF ( Lateral Distribution Function) p Integral spectrum Normalization point for Tunka-133 σ sys (E) = 8%

11. 3 winter seasons of the array operation: 165 moonless nights with good weather, 971 hours Tunka-133 was installed in 2009 - 2009 – 2010: 286 hours of good weather ( November 2009 – March 2010) - 2010 – 2011: 305 hours of good weather (October 2010 – April 2011) -2011 – 2012 : 380 hours of good weather (October 2011 – April 2012) > 6  10 6 events with energy  10 15 eV.

12. IN-events: Core position inside circle: R < 450m Zenith angle < 45° 2009-2012 >10 16 eV: 63490 >10 17 eV: 605 OUT- events: R <800 m > 10 17 eV: 1900 800 m 450m

14. Tns T ns = (R+200/R 0 ) 2 ×3.3 ns Shower front

15. ADF LDF ADF – amplitude distant function is used for core location WDF – width distant function WDF

17. Shower front

19. Accuracy of out -events reconstruction With external clustersWithout external clusters = 0.02 E1 E2 σ (lg (E1/E2)) =0.05

20. 1900 events > 10 17 eV 6 21 48 Combined energy soectrum

21. Comparison of spectras 2009 -2011 2009-2012

22. γ~ 3.0 γ~ 3.3 Second knee ~3 ·10 17 eV

23. γ 1 = 3.24 ±0.01 γ 2 = 2.97 ±0.01 γ 3 = 3.4 ±0.14

24. γ 3 = 3.12 ±0.05

25. OUT-events in 1000 m radius Second knee at (2-3) 10 17 eV seems to be more adequate to the data

29. E shift = 0.95· E 0 σ sys (E) = 8% At E= 6 10 15 eV From QUEST experiment σ sys (E) = 15% At 10 18 eV due to uncertainty in g

31. Conclusions 1. The spectrum in the energy range of 10 16 to 10 18 eV cannot be fitted with single power law index 3.24 ±0.01 (6·10 15 – 2·10 16 eV) 2.97 ±0.01 (2·10 16 – 10 17 eV) 3.40 ± 0.14 (3 ·10 17 – 10 18 eV) 2.There is an indication on the second knee at ~3·10 17 eV 3. Tunka spectrum = K-Gr spectrum inside energy reconstruction systimatics. The key question – to increase accuracy of absolute energy calibration. Is it possible to have 5% accuracy? 4. More statistics is needed at the energy range 10 17 – 10 18 eV The array will continue data taking for another 4-5 seasons.

32. Plans for upgrading I 1. Deployment of scintillation array for the absolute energy calibration at 3·10 16 – 10 17 eV (the new QUEST experiment). 2. Deployment of fluorescent detector at 7-10 km distance from the array for joint operation.

33. Absolute energy calibration experiment. Repeating the “QUEST” at 10 16 -10 17 eV -20 scintillation counters, 10 m 2 Lg (Ne / E, Tev) p -P -Fe Zenith-angle: 0º -45º Energy: 10 16 – 10 17 eV P – steepness of LDF 2000 events with E >3·10 16 eV per season

34. Cross calibration of Cherenkov light and fluorescent light methods. Image detector from TUS experiment 7-10 км S= 2 -10 м 2 Угол обзора ± 7 град

35. Frenel mirror for TUS experiment

36. Plan for upgrading II -Net of radio antennae ( poster of F.Schreoder) Tunka-REX ( Radio Extension) - Gamma astronomy at Tunka (report of M.Tluzcykont)

37. HiSCORE Tunka : 2013 M.Tluczykont, July 6, Friday F.Shreoder, poster,

38. Thank you

39. 20-30km P, A For E e >25 MeV V e > C/ n – light velocity in air Cherenkov light Photons detectors Q tot ~ E Atmosphere as a huge calorimeter E (PeV) = 0.4 Q(175) ph· ev -1 cm -2 Lateral Distribution Function

40. Advantage of Cherenkov Technique: 1. Good energy resolution - up to 15% 2. Good accuracy of X max - 20 -25 g/cm 2 3. Good angular resolution - 0.1 – 0.3 deg 4. Low cost – Tunka-133 – 1 km 2 array: 0.5 10 6 Eur ( construction and deployment) + 0.2 10 6 Eur( PMTs) 100 km 2 array - 10 7 Eur Disadvantage: 1.Small time of operation ( moonless, cloudless nights) – 5-10%

41. “ Bump” ( at 8·10 17 eV ) and background

42. New approach to core reconstruction A(R) = A(400)·((R/400+1)/2) -b Q(R) = Q(300)·((R/300+1)/2) -b QDF