liquid xe detector for m + g e + g search

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Liquid Xe detector for Liquid Xe detector for m m + + + g g searc searc h h Kenji Ozone ICEPP, Univ. of Tokyo, Japan Introduction prototype R&D ー PMTs ー small & large type summary Outline Outline

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Liquid Xe detector for m + g e + g search. Ke n ji Ozo n e ( ICEPP, Univ. of Tokyo, Japan ). Outline. Introduction prototype R & D   ー  PMTs   ー  small & large type summary. Three Talks. XENON01. LXe detector for m g e g search. Kenji Ozone. - PowerPoint PPT Presentation

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Page 1: Liquid Xe detector for  m + g e + g  search

Liquid Xe detector for Liquid Xe detector for mm++ ee ++gg search search

Kenji Ozone( ICEPP, Univ. of Tokyo,

Japan )

Introduction prototype R&D  ー  PMTs  ー  small & large typ

e summary

OutlineOutline

Page 2: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

Three TalksThree Talks     XENON01

NOON2001

LXe detector for meg searchKenji Ozone

Pulse tube refrigerator for liquid xenonTomiyoshi Haruyama

meg : status and prospectsWataru Ootani

Page 3: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

CollaborationCollaboration

RussiaRussiaLXe Tests andPurification

ItalyItalye+ counter, Trigger, M.C.LXe Calorimeter

●●

SwitzerlandSwitzerlandDrift Chamber,Beam Line, DAQ

JapanJapan

LXe Calorimeter, Superconducting Solenoid, M.C.

Page 4: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

Physics MotivationPhysics Motivation

Ootani’s Talk

NOON01 08/NovDetail

Beyond the SM (SUSY)

Br(meg) < 1 x 10-14

High Performance Detector

Keywor ds

Page 5: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

Detector for Detector for mm++ ee ++gg search at PSI search at PSI

γγ●●

●●

Liquid Xe Calorimeter

Drift ChamberTiming Counter

Compensation Coil

COBRA Magnet

Surface m(108 sec-1 )

Page 6: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

Kamiokande-like

SUS honeycomb

compact PMTs

Final Liquid Xenon DetectorFinal Liquid Xenon Detector

PMTs IN LXe

Low X0 Materials

~ 800 PMTs

~ 800 liter LXe

g

Page 7: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

M.C. simulation (GEANT3)M.C. simulation (GEANT3)

Position resolution   x, y ~ 4mm, z ~ 16mm FWHM

Energy resolution :  1.4% FWHM

Page 8: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

Why Liquid Xenon ?Why Liquid Xenon ?

τττ

NaI: too slowCsI, BGO: poor resolution at 52.8MeV Inhomogeneous to cover large area

crystal scintillators

Page 9: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

PMT (HAMAMATSU R6041PMT (HAMAMATSU R6041QQ))

––

32 mm

57 mm

Quartz

Page 10: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

Small PrototypeSmall Prototype

●g source (137Cs, 51Cr, 54Mn, 88Y)●a source (241Am) for PMT calibration●LED for gain adjustment

■ 2.34 liter Liquid Xe■ 32 PMTs

Page 11: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

Energy ResolutionEnergy Resolution

~1% in s is expected at 52.8MeV.

Fitted with asym. Gaussian

Page 12: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

Position ResolutionPosition Resolution• PMTs are divided into two gro

ups by the y-z plane.– γ int. positions are

calculated in eachgroup and thencompared witheach other.

– Position resolutionis estimated as     sz1-z2/√2

• Possible to achieve for 52.8MeV gA few mm in position meas.

Page 13: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

Time Resolution (small prototype)Time Resolution (small prototype)• PMTs are divided again into two groups by the y-z plane.• In each group the average of the time measured by TDC is c

alculated after slewing correction for each PMT.• The time resolution

is estimated bytaking the differencebetween two groups.

• Resolution improvesas ~ 1/√Npe

• s<50psec at 52.8 MeV.

M.C. expects~ 20,000 p.e. @ 52.8 MeV

Page 14: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

Brief Summary on Small PrototypeBrief Summary on Small Prototype

• Energy; ~1%• Position; a few mm• Time; ~50psec

in s at 52.8MeV

Go to the next Go to the next stage!!stage!!

Large PrototypeLarge Prototype

Go to the next Go to the next stage!!stage!!

Large PrototypeLarge Prototype

Extrapolation to Higher Energy

Page 15: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

Large PrototypeLarge Prototype

g

Page 16: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

Purpose of Large PrototypePurpose of Large Prototype

Pre-Final Detector Test for detector components PMTs, feedthroughs(HV, signal), refrigerator, vacuum chamber, cables, PMT holder, DAQ, …

Performance Test

Energy, Time, Position

Small proto: < 2MeV …… Compton scat.

Large proto: < 40 MeV … pair creation

Attenuation Length Measurement

Page 17: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

Inside Inside ー ー Mini-KamiokandeMini-Kamiokande

Large Prototype

Small Prototype372 mm

496 mm

372 mm

(116x116x174 mm3)

Xe [liter] PMTs

SMALL 2.34 32

LARGE 68.6 228

FINAL ~800 ~800

Page 18: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

1st Beam Test 1st Beam Test For 1 weeks in June, 2001

Compton Edge~ 43 MeV

ADC broken . . .Pedestal shiftADC overflow

Most of data became unavailable

survived

data

AIST, Japan

Everything worked very well.Everything worked very well.But …

Page 19: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

Gain adjustment with LEDsGain adjustment with LEDs

● 8 LEDs inside PMT holder● Scan HV to get gain curves for all PMTs

■ Gain = 2 ×106

■ Gain was roughly adjusted.

Typical gain curve

In LXe

Page 20: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

After 1st Beam TestAfter 1st Beam Test

First Beam Test in June Every components tested. All OK! Ready for next test.

Attenuation Length Measurement with Large Proto

Now running and analyzing (to be talked someday)

Second test scheduled in Sep. was suspended

by the machine trouble at AIST. Next Beam test @ AIST at the beginning of 2002y

Page 21: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

Step1PMT1:Absorption + Scattering Length

measurementPMT2: used as a reference.Collimators to prevent scinti. light from

hitting the wall.Mask in front of PMT1 to define the ill

uminated area on the photo cathode.

Step1PMT1:Absorption + Scattering Length

measurementPMT2: used as a reference.Collimators to prevent scinti. light from

hitting the wall.Mask in front of PMT1 to define the ill

uminated area on the photo cathode.

Step2PMT2: Scatt. Length meas.PMT1: reference at a fixed point.

Step2PMT2: Scatt. Length meas.PMT1: reference at a fixed point.

dL/L ~ 5 x L(m) [%]

A Plan A Plan for Attenuation Length Measurementfor Attenuation Length Measurement

LN2

X - ray

PMT1

PMT2

Page 22: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

Small Prototype Result in successful expected performance at 52.8 MeV; sE ~ 1%, s t ~ 50 psec, spos ~ a few mm

Large PrototypeThe next beam test is scheduled at the beginning of next year. Attenuation length measurement with cosmic ray in Tsukuba, Japan

Others Attenuation length measurement

with X-ray source in Novosibirsk, Russia

SummarySummary

Page 23: Liquid Xe detector for  m + g e + g  search

End of TransparenciesEnd of Transparencies

Page 24: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

• μ beam stopped on the target 108/sec – Ee=52.8MeV Eγ=52.8MeV

Back to back, in time

• Sensitivity– Nm=1x108/sec, 2.2x107 sec running Ω/4π=

0.09,εe=0.95, εγ=0.7, and εsel=0.8 Single Event sensitivity : 0.94x10-14

• Main background sources– Radiative μ+ decay– Accidental overlapNOT back to back, NOT in time Reduced down to 10-15 level

Signal and BackgroundsSignal and Backgrounds

e

γν

ν?

e

γμ

e

ν

ν

γ

Page 25: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

Physics MotivationPhysics Motivation

●MEGA (~ 1999 )  Br <1.2×10-11 ●SINDRUM II  (μ e conversion search)

●SK (neutral lepton)●Anomalous Muon (g-2)

SU(5) SUSY

Associated Topics

1) J. Hisano et al., Phys. Lett. B391 (1997) 3412) MEGA collaboration, hep-ex/9905013

m e g search is a promising field to find physics beyond the SM

Page 26: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

What’s the difference ?What’s the difference ?

Xe [liter] PMTs Eg[MeV]

SMALL 2.34 32 0.3 ~ 1.8

LARGE 68.6 228 20 ~ 40

FINAL ~800 ~800 ≦ 52.8

Page 27: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

front facefront faceX0 (cm) thickness

LXe 2.87 ―

G10 19.4 0 ~ 0.15 X0

Lucite 34.4 0.009 ~ 0.04 X0

RTV 10~30? 0 ~ 10 –2 X0

Al W

ind

ow

SU

S

Hon

eycom

b

PM

T

Conversion

γ Xe

Max 0.23 X0

Page 28: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

ADC troubleADC trouble

Some broken amps on an ADC caused heavy damage to many amps on all ADCs.

Impossible to estimate resolutions with all PMTs.

overflow

overflowoverflow

overflow

Pedestal shift

Page 29: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

Position resolution (preliminary)Position resolution (preliminary)● Survived 10 PMTs were divided into two groups,

Upper and Lower.

● Estimated position in each group was compared with each other.

Page 30: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

Timing resolution (preliminary)Timing resolution (preliminary)

● Similarly to the small type, calculated by taking the difference between two groups.

●ADC trouble prevented from making slewing correction and selecting adequate events.

st  ~ 400 psec

If slewing correction had been made, this tail would have been put together into the peak.

Page 31: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

AnalysisAnalysis• Position of g interactio

n:Weighting the position of the PMTs with their individual pulse heights

• For selecting the fully contained events:Requiring the g int. position should lie within a central region of 2cmx1cm

Page 32: Liquid Xe detector for  m + g e + g  search

03/Dec/2001 K. OzoneXenon01 Workshop @ ICRR, Univ. of Tokyo, Kashiwa, Japan

AnalysisAnalysisg-ray● Not be tagged by electron● Energy is not monochromatic ( Compton edge )● Focused with a 1-mm collimator

ResolutionsResolutions■ Energy is estimated by means of the spread of Compton edge.■ Position is calculated as the difference of position estimated in two groups.(like the case of small ptototype)■ Time is the difference of the average timeestimated in two groups.

Compton Edge~ 43 MeV