Status of the DCBA DCBA Experiment DCBA : D D rift C C hamber B B - - PowerPoint PPT Presentation

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Status of the DCBA DCBA Experiment DCBA : D D rift C C hamber B B - - PowerPoint PPT Presentation

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Status of the DCBA DCBA Experiment DCBA : D D rift C C hamber B B eta-ray A A nalyzer DCBA Nobu ISHIHARA (KEK) for the DCBA collaboration Contents 1. Introduction to DCBA 2. DCBA-T2 in engineering run 3. DCBA-T3 under construction 4. Future

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SLIDE 1
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

1

Status of the DCBA DCBA Experiment

DCBA DCBA: D Drift C Chamber B Beta-ray A Analyzer

Nobu ISHIHARA (KEK) for the DCBA collaboration

Contents

  • 1. Introduction to DCBA
  • 2. DCBA-T2 in engineering run
  • 3. DCBA-T3 under construction
  • 4. Future prospect of DCBA/MTD
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SLIDE 2
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

2

Introduction to DCBA

Momentum analyzers to study ♦ Majorana nature by searching for 0νββ ♦ Effective neutrino mass by measuring

ν 2 / 1

T

Advantage of DCBA ♦ Background elimination by particle ID ♦ Characteristic pattern of ββ in a magnetic field ♦ Decay vertex determination ♦ Energy measurement of individual β (e-) ♦ Angular correlation between ββ Disadvantage ♦ Energy resolution (FWHM≈100 keV) worse than Ge and Te calorimeter ♦ Low detection efficiency (≈30%) ♦ Large space for decay source installation

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SLIDE 3
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

3

Principle of electron detection in DCBA DCBA

Gas:He(90%)+CO2(10%)

Y Z X

Momentum Acceptance p(MeV/c)=0.3r(cm)B(kG) B≈2 kG 2 cm < r < 5 cm ⇓ 1.2 MeV/c < p < 3 MeV/c Energy Acceptance for e- 0.8 MeV < T < 2.5 MeV α is automatically rejected T=1 MeV → p≈ 87 MeV/c

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SLIDE 4
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

4

B

Z X Y Source plate (150Nd) Drift Chambers Solenoid Magnet

DCBA-T2

X Y VTX β2 β1 Z X VTX β1 β2

150Nd

(100Mo) plate

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SLIDE 5
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

5

Cathode 360 440 Source Plate Anode SIDE VIEW

DCBA-T2 drift chamber

Sensitive vol. : 18(x)×24(y)×24(z) [cm3] Gas : He (90%) + CO2(10%) Magnet : solenoid magnet 0.6 - 0.8 [kG] TOP VIEW 540 Pickup FRONT VIEW Source Plate Anode Pickup

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SLIDE 6
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

6

Straight track of a cosmic ray

X Y X Z

B 2 A1 B1 A2

4cm 24 cm 7 . 2 c m

A B A1 B1 A2 B2 Z X Y

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SLIDE 7
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

7

Position resolution of DCBA-T2

  • X

Y 6 6

F i t t e d l i n e

Measured point

σX 1.00mm σY 0.21mm σZ 0.17 mm

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SLIDE 8
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

8

Energy measurement of an I. C. electron from 207Bi

x

x

y z

B

Z X Y

207Bi point source

Z X Y

Energy = 1073keV

207Bi point source 207Bi point source

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SLIDE 9
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

9

Energy resolution of DCBA-T2

FWHM ≈0.15 MeV 1.05 0.98

Including Backgrounds

(7 : 2.4)

Energy spectra of internal conversion electrons from207Bi

Expected ∆E/E at Q = 6.3% (FWHM) for 150Nd

976keV 1050keV

Monte Carlo

FWHM ≈150keV @980keV

Chamber conditions He(90%)+CO2(10%) 1atm B=0.8 kG Wire pitch=6 mm

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SLIDE 10
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

10

Other BGD events (1)

pair creation x y x z Alpha-ray x y x z α

−

e

+

e

−

e

+

e

α

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SLIDE 11
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

11

Double Buffer FADC against Background Events

sec) 164 ( Pb conv. Po Bi

2 / 1 210 82 214 84 214 83

µ α ν β = + ↓→ ↓→ + + →

− −

T e

(Q=3.28MeV)

2e- Background Double buffer FADC

Test pulse input

40 µs 40 µs 160 µs

Memory 1 Memory 2

160 µs

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SLIDE 12
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

12

Engineering run of DCBA-T2 using

Natural Mo source plate of 45 mg/cm2 thick

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SLIDE 13
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

13

DCBA-T2 after installing Mo

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SLIDE 14
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

14

Detection Efficiency for 2νββ in DCBA-T2

  • Nat. Mo

(10% 100Mo) 45 mg/cm2 B=0.6 kG Back-to-back

0.6 kG Back-to-back 0.6 kG All direction

0 kG All direction

ε = 9.5%

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SLIDE 15
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

15

Back-to-back event of DCBA-T2 (Candidate of 2νββ)

X Y X Z

Time gap Natural Mo plate (10% 100Mo)

(45 mg/cm2)

35 30 25 20 15 10 5 Anode wire number

5 10 15 20 25 30 35

Pickup wire

10 µsec ≈ 5 cm 0.3 MeV 0.6 MeV

FADC counts/10 ns

Helical Radius: r Azimuth Angle: ϕ Pitch Angle: λ

B = 0.8 kG Wire pitch = 6 mm

090505-39_12

cosλ=0.985 cosλ=0.457

Opening angle θ≈120 deg

cosθ=−0.5

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SLIDE 16
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

16

214Bi (Uranium decay series) 214Po

1.42 MeV

3.27 MeV

βmax=1.85 MeV (e1=0.342 MeV)

  • conv. elec.

(e2=1.369 MeV)

0+

0+

e1=0.342 MeV r1=23.9 mm

Back-to-back event probably coming from 214Bi

e2=1.369 MeV r2=34.1 mm cosλ1=0.839 cosλ2=0.452

X Y Z X

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SLIDE 17
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

17

LY(-614, 28, Z) LZ(-626, Y, 20) RY(621, 30, Z) RZ1(623, Y, 18) RZ2(636,Y, 21) 12 mm X-Y plane X-Z plane r=21.1 mm T=1.14 MeV cosλ=0.321

10FADC counts ≈ 0.5 mm

090505-52_14

T=0.32 MeV r=26.3 mm cosλ=0.963

Background Event / Double Compton?

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SLIDE 18
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

18

DCBA-T3 (under construction)

5 cm 57 cm 57 cm

976 keV 1500 keV Geant4 Geant4 2.4 kG 60 keV Nd2O3 40 mg/cm2 80 keV Nd2O3 40 mg/cm2 2.4 kG ε≈52% ε≈60% SC-magnet

Refrigerator

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SLIDE 19
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

19

Differences between DCBA-T3 and T2

  • Drift chamber

Mini-jet chambers with multi-particle separation capability DCBA-T3 DCBA-T2 Source Nd2O3 (40 mg/cm2 ×13,760 cm2 Nd2O3 = 550 g :150Nd = 0.18 mol) 150Nd = 0.008 mol Sensitive vol. 8 × (4(X) × 44(Y) × 44(Z)) cm3 9(X) × 26(Y) × 26(Z) cm3 4 × (4(X) × 20(Y) × 44(Z)) cm3 Anode pitch 3 mm 6 mm Pickup pitch 3 mm 6 mm Signal readout Flash ADC Flash ADC X-position Drift vel. × time : σX ≈ 0.5 mm σX ≈ 1 mm Y-position Anode position : σY ≈ 0.2 mm σY ≈ 0.2 mm Z-position Pickup position : σZ ≈ 0.2 mm σZ ≈ 0.2 mm

  • Magnet

SC-solenoid + F.R.Y. Normal-sol.+ F.R.Y. Magnetic field 3.0 kG (Max.) 0.8 kG (Max) Uniform Vol. 80 dia. x 60 cm3 δB/B0 < 1% 40 dia. x 60 cm3 δB/B0 < 1%

∆E/E expected at Q < 5% (FWHM) 6.3% (FWHM) Power consumption 1 kW (refri.)+10 W (power supply) 9 kW (Power supply)

  • Natul. Mo:32g

100Mo=0.03 mol

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SLIDE 20
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

20

EVENT

Start

Pickup Anode

Magne t

CompactPCI

Start/Stop Trigger

DCBA-T3

CPU Board

32ch Pre-Amp & FADC module FPGA with Memory

STOP

Trigger Board DAQ Board

DCBA-T3 Electronics and DAQ

Serial LVDS cable（Digital transfer）

FPGA MEMORY Anode / 160ch Pickup / 160ch

Chamber 4 Layers 1,280ch (1st stage)

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SLIDE 21
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

21

Chamber cell : the same as DCBA-T3, Source plate: 80 m2/module Thickness: 40 mg/cm2, Source weight: 32 kg/module

MTD (Magnetic Tracking Detector: temporary name) module after DCBA

3500

Expected Energy Resolution

% 4 . 3 ) keV 3370 ( keV 80 2 ) ( FWHM

150

  • Nd

≈ × = Q Esum

Energy (MeV) 0 1 2 3 FWHM @ 1.7 MeV 80 keV Geant4 2.4 kG

He+CO2(10%)

Nd2O3 40 mg/cm2

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SLIDE 22

Conditions

  • Assumed effective mass is 50 meV.
  • Used are from

and

  • 50 modules of MTD are operated.
  • Source thickness is 40 mg/cm2: thus 30 kg/mod × 50 mod = 1500 kg.
  • Event rate is obtained by

where ε is the detection efficiency (=0.3) and N0 the number of nuclei. Amount (mol) 560 6000 13500 16460 17760 Natural Nd 150Nd 100Mo

82Se 76Ge

(5.6%150Nd) (60% enr.) (90% enr.) (90% enr.) (90% enr.) Source Item

Expected event rate in MTD

> <

ββ

m

ν 2 / 1

T

ν

ε

2 / 1

/ 2 ln T N n =

Faessler (y) 3.55×1025 3.55×1025 3.33×1026 3.50×1026 1.10×1027 Event rate (y−1) 2 21 5 8 2 Staudt (y) 1.35×1025 1.35×1025 5.08×1026 2.41×1026 9.32×1026 Event rate (y−1) 5 55 3 9 2

ν 2 / 1

T

ν 2 / 1

T

Faessler et al. presented at TAUP2009

  • A. Staudt et al. in Europhys. Lett. 13 (1) (1990) 31.
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

22

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SLIDE 23
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

23

DCBA DCBA collaboration

  • N. Ishihara1, G. Iwai1, H. Iwase1, Y. Kato1, M. Kawai1,
  • Y. Kondou, T. Haruyama1, T. Inagaki1, Y. Makida1,
  • T. Ohama1, K. Takahashi1, S. Takeda1, Y. Yamada1,
  • H. Igarashi2, T. Ishikawa2, T. Sumiyoshi2, E.Tashiro3,
  • T. Ishizuka3, S. Kitamura4, Y. Teramoto5, I.Nakano6,
  • Y. Sakamoto7, Y. Nagasaka8, N. Tamura9, K. Tanaka10,
  • R. Ito11,

1KEK, 2TMU, 3Shizuoka Univ., 4NMS, 5OCU, 6Okayama Univ., 7TGU, 8HIT, 9Niigata Univ., 10SSI, 11Futurescope

(26 persons from 11 Institutes)

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SLIDE 24
  • Oct. 10-13, 2009
  • N. Ishihara at DBD09, Hawaii

24

Conclusions

  • 1. DCBA is momentum analyzers for studying neutrinoless

double beta decay.

  • 2. DCBA-T2 has taken DBD candidates from natural Mo source

plates of 45 mg/cm2 thickness, which include 10% 100Mo.

  • 3. DCBA-T3 is now under construction at KEK, being expected

to have the energy resolution of less than 100 keV (FWHM) for each electron in the energy range of 1 – 2 MeV.

  • 4. Magnetic Tracking Detector (MTD: named temporarily) is the

future project based on DCBA. The energy resolution of MTD is expected to be less than 4% (FWHM) at the Q-value of

150Nd (3.37 MeV). MTD of 50 modules will make it possible

to investigate the effective neutrino mass down to 50 meV.