2. 06.06F.Suekane, KASKA1 Status of KASKA F.Suekane RC S, Tohoku Univ. Japan suekane@awa.tohoku.ac.jp @ Double CHOOZ collaboration meeting 2006.06.06-08 (Kashiwazaki-Kariwa Nuclear Power Station)

3. 06.06F.Suekane, KASKA2 Outline Brief introduction of KASKA experiment R&D status Fund requesting status Summary

4. 06.06F.Suekane, KASKA3 Niigata University: N.Tamura, M.Tanimoto, H.Miyata, H.Nakano T.Kawasaki, M.Katsumata, T.Iwabuchi, M.Aoki, N.Nakajima, K.Sakai Tohoku University: F.Suekane, Y.Sakamoto, S.Tsuchiya, H.Tabata Tokyo Metropolitan University: T.Sumiyoshi, H.Minakata, O.Yasuda, K.Sakuma Tokyo Institute of Technology: M.Kuze, K.Nitta, H.Furuta, J.Maeda, Y.Funaki Kobe University: T.Hara KEK: N.Ishihara, H.Sugiyama Miyagi University of Education: Y.Fukuda, Akiyama Hiroshima Institute of Technology: Y.Nagasaka Osaka University: Nomachi KASKA Members ~30people

5. 06.06F.Suekane, KASKA4 Kashiwazaki-Kariwa NPS 7 powerful reactors (5BWR+2ABWR) cluster into two groups >2010 World's Highest Power P=24.3GWth =Strongest luminosity

6. 06.06F.Suekane, KASKA5 KASKA-  13 Geometry ~1.6km 150m ~0.35km 24.3GW 6ton x 2 ~50m 2x6ton L=1.6km Can return to L=1.3km

7. 06.06F.Suekane, KASKA6 Detector & Shaft Hole

8. 06.06F.Suekane, KASKA7 Structure of KASKA Detector is similar to DCHOOZ's

9. 06.06F.Suekane, KASKA8 Error efficiency related + flux + BKG Statistic error = 0.4% with 3years run

10. 06.06F.Suekane, KASKA9 Expected Sensitivity (rate only analysis) SK  m 2 10x better sensitivity than current CHOOZ limit

11. 06.06F.Suekane, KASKA10 R&D * Boring study at near-B site * Prototype detector * Low BKG PMT * Electronics development * LS developments * Detector and Shaft hole design study * Calibration system * Cosmic-ray tracking system * Design and tests of acrylic vessels

12. 06.06F.Suekane, KASKA11 Prototype Detector * Test of  -catcher. * Am/Be e like signal. * Cosmic-ray spallation BKG.  e detection at research reactor. *Magnetic shield test * MC development Gd-LS Am/Be Sources (4.4MeV  +n) 0.9m 3

13. 06.06F.Suekane, KASKA12 Data Simulation 60cm thick spherical buffer layer preliminary Need to tune the simulation. Gd 8MeV peak d 2.2MeV peak Ed

14. 06.06F.Suekane, KASKA13 Prototype @ a research reactor Joyo Research Reactor, 140MW Fast Reactor Frequent ON/OFF ~150 reaction/day ( flux ~KASKA near) data taken with very poor  shields no cosmic-ray veto Window (BKG~50/day) BKG data after some improvements Demonstrate detection capability First fast reactor detection (Pu origin) 2006/8~ Ed Ep 25m

15. 06.06F.Suekane, KASKA14 Boring Study @ near-B site ( 2004.10~11 ) Reactor Building #6 scaffold tower for boring machine Reactor Building #5 BKG measurement counting hut Study of Geology Cosmic-ray BKG  -ray BKG at real location and depth & Real experience to work in the reactor site 70m depth

16. 06.06F.Suekane, KASKA15  -ray BKG data MC. E(KeV) Preliminary 238 U/ 232 Th/ 40 K=2.1/6.3/1.5ppm Preliminary MC data Cosmic-ray BKG Tuned MC with 20% accuracy

17. 06.06F.Suekane, KASKA16 Geology -> shaft hole design

18. 06.06F.Suekane, KASKA17 Liquid Scintillators Region-I( -target): PaloVerde Type BC521:PC:Tetradecane=20:20:60v% Gd=0.1%. Light Output~50% Anthracene Region-II(  -catcher): PC:TD=15:85% + PPO+bis-MSB LO~50% Anthracene Region-III(Buffer Oil): Paraffin Oil(+PPO LO~5%Anth. optional)

19. 06.06F.Suekane, KASKA18 LS long term stability tests (preliminary) BC521 : Pseudocumen(PC) : Tetradecane(TD) = A ‥ 20% : 20% : 60% B ‥ 30% : 10% : 60% C ‥ 20% : 10% : 70% T=20deg T=30deg T=40deg No aging at room temp. for 240days KASKA candidate

20. 06.06F.Suekane, KASKA19 PMT TTS=2.5ns Low BKG Glass Hamamatsu 10"PMT It is possible to make10"PMT glass as low BKG. ~300/detector 10% coverage 1pe signals

21. 06.06F.Suekane, KASKA20 Issue of Geo-Magnetic Field (1) 11cm thick iron tank (2) Compensation Coil (3) high-  metal shield on each PMT  (3) works well for prototype detector Issue of cosmic-ray saturation ( to measure shower energy)  Install small PMTs to measure cosmir-ray & shower energy

22. 06.06F.Suekane, KASKA21 Electronics * Full digital treatment using FADC & FPGA * Bank system to kill deadtime * Quick recovery from saturation Test module

23. 06.06F.Suekane, KASKA22 Cosmic-ray tracker To estimate long-life spallation Backgrounds such as 9 Li. * Liquid Scintillator base * Plastic Scintillator base

24. 06.06F.Suekane, KASKA23 Beam test of plastic scintillator

25. 06.06F.Suekane, KASKA24 Calibration: Wire manipulation Mechanical Test Test at prototype (planning) weight hook Source (between PMTs)

26. 06.06F.Suekane, KASKA25 Designing Work With KEK Engineering Div.

27. 06.06F.Suekane, KASKA26 Inner acrylic vesselOuter acrylic vessel

28. 06.06F.Suekane, KASKA27 1/2 scale inner acrylic dorm.  =90cm, t=1cm) -> manufacturing method. -> Test of achievable precision

29. 06.06F.Suekane, KASKA28 LS compatibility acceleration test (35 deg) of acrylic joint 1day 1week 1month Before soak After soak Some incompatibility was Observed. Now we think we know how to avoid this effect

30. 06.06F.Suekane, KASKA29 Construction sequence

31. 06.06F.Suekane, KASKA30 LoI will appear in ArXiv soon. ~80 pages

32. 06.06F.Suekane, KASKA31 Funding schemes: possible 3 ways * Budget request as University Project * Grant in Aid for Scientific Research * Support from KEK 2006 2005 2007 Now Funding Issue 1st review [End of August] (If it fails, we would like to join to DCHOOZ here) As DCHOOZ request(Sep.-Oct.) We would like prepare the request form from now. If GASR is approved the fund will be available from here. JFY (Apr.-Mar.) If KEK decides to support us, we may be able to start before next JFY starts.

33. 06.06F.Suekane, KASKA32 Summary (1)KASKA uses highest reactor power, optimum baseline and can measure sin 2 2  13 with 10 times better sensitivity of current limit. (2) R&D has been progressing. (3)Now struggling for funding. We will know in the end of August if our final trial fails. (4) In that case, we would like to join DCHOOZ and do next budget request for DCHOOZ. If the request is <$5M, the probablity of approval is high. (5) In any case we would like to start to plan the next budget request as DCHOOZ.