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1/41 LXe Beam Test Result CEX beam test 2004 Cryogenic Equipment Preparation Status Liquid Xenon Photon Detector Group

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LXe Beam Test Result. CEX beam test 2004 Cryogenic Equipment Preparation Status Liquid Xenon Photon Detector Group. Charge Exchange Beam Test at piE5. New PMTs R9288TB higher QE and better performance under high BG Resolutions to be improved New calibration alpha sources - PowerPoint PPT Presentation

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Page 1: LXe Beam Test Result

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LXe Beam Test ResultCEX beam test 2004

Cryogenic Equipment Preparation Status

Liquid Xenon Photon Detector Group

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Charge Exchange Beam Test at piE5

New PMTs R9288TB higher QE and better performance under high BG Resolutions to be improved

New calibration alpha sources New refrigerator with higher cooling power TEST at piE5 beam line

Gain experience Analysis framework

ROME in online (offline also) analyses Waveform data obtained with DRS prototype

boards

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1st generation R6041Q 2nd generation R9288TB 3rd generation R9288ZA

228 in the LP (2003 CEX and TERAS)

127 in the LP (2004 CEX)

111 In the LP (2004 CEX) Not used yet in the LP

Rb-Sc-Sb

Mn layer to keep surface resistance at low temp.

K-Sc-Sb

Al strip to fit with the dynode pattern to keep surface resistance at low temp.

K-Sc-Sb

Al strip density is doubled.

4% loss of the effective area.

1st compact version

QE~4-6%

Under high rate background,

PMT output reduced by 10

-20% with a time constant of

order of 10min.

Higher QE ~12-14%

Good performance in high rate BG

Still slight reduction of output in very high BG

Higher QE~12-14%

Much better performance in very high BG

PMT Development Summary

Page 4: LXe Beam Test Result

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Alpha sources on wires

4 tungsten wires plated with Au (50 micron )

Po attached on the wires, 2 active points per wire

~40Bq per point on 2 wires at the rear side

~130Bq per point on 2 wires at the front side

Active points are coated with Au (200-400Å)

Fixed on the wall with spring. Alpha sources on the walls were

removed

gamma

wire

LED

Page 5: LXe Beam Test Result

5

New Refrigerator (PC150W)

MEG 1st spin-off Technology transferred to a

manufacturer, Iwatani Co. Ltd

Performance obtained at Iwatani

189 W @165K 6.7 kW compressor 4 Hz operation

Page 6: LXe Beam Test Result

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CEX Elementary process -p0n

0(28MeV/c) MeV

eV

• Requiring

FWHM = 1.3 MeV

• Requiring > 175o

FWHM = 0.3 MeV

170o

175o

0

54.9MeV 82.9MeV

1.3MeV for >170o

0.3MeV for >175o

Page 7: LXe Beam Test Result

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Beam Test Setup

H2 target+degrader

beam

LPNaI

LYSO

Eff ~14%

S1Eff(S1xLP)~88%

Page 8: LXe Beam Test Result

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Beam Condition Profile at the target (with a pill

counter) Vertical 13.2mm Horizontal 9.9mm

Pion rates (w/o separator) 1.8mA and 4cm Target E.

Slits 80:      2.07 x108 п -/sec Slits 100:    3.95 x108 п - /sec

Profile at S1, 2mm/bin

Optimization of degrader thickness20mm + 3.3mm x n

Page 9: LXe Beam Test Result

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Operation Status

Thanks to a new refrigerator we succeeded to operate the detector (almost) without using LN2 except for power break and recovery.

New pressure reducer also helped this while pre-cooling and liquefaction.

Circulation/purification continued during DAQ. History

September• 18~21 Pre-cooling (72 hrs)• 21~24 Liquefaction (79 hrs)• 24 Circulation start (~30 cc/min)• 24 Electronics setup

October DAQ started 25 DRS boards installed 29 Recovery of xenon

Page 10: LXe Beam Test Result

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Data set

Gain ADC gate Beam intensity event# *

High

400 nsec

Low -

middle 32 + 29** k

high -

600 nseclow -

middle 48 k

high -

Normal

400 nsec

low 55 k

middle 110 + 44** k

high -

600 nsec

low 77 k

middle 85 k

high 47 k

And Waveform data…

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Analysis Result

CalibrationEnergy Timing

1st look on waveform Data

Page 12: LXe Beam Test Result

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Alpha data

One of the rear wires found to be slipped Weighted position average surround wires

due to shadow effect. Reconstructed Position is far from wires

Wire (50 μm ϕ)

Alpha

40 μm Po half-life=138 days

Page 13: LXe Beam Test Result

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The two wires on the front face are a little displaced

LXe GXe

Source Position Reconstruction

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Alpha data analysis

Nphe[0]

Nphe[0] for top-left alpha

Center of the PMT-0

with alpha emission angle selection

Page 15: LXe Beam Test Result

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LXe/MC, absorption length evaluation

Applying the QEs determined in GXe (-75˚C)

4 front sources

Page 16: LXe Beam Test Result

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Q.E. evaluation with alpha events in liquid

R9288

R6041

Data #8528 normal gain front 4 alphas

MC reflection on quartz on no absorption scattering length :45cm for 175 nm

Q.E. evaluation using alpha data in the liquid is also possible.

Higher light yield Expected better evaluation if xenon is pure!

Page 17: LXe Beam Test Result

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Energy Reconstruction

Cut-based Qsum Analysis

Linear Fit Analysis

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Cut-based Qsum analysisEvent Selection

83 MeV to Xe83 MeV to Xe

55 MeV to Xe55 MeV to Xe

Cut-based Qsum analysis

MCMC

Exe

non[

n ph]

Analyze only central events to compare with the previous result

|Xrec|, |Yrec|<2cm 70 MeV < ENaI+ELYSO < 105MeV Sigma2 > 40 (discard events if shallow)

Sigma2: broadness of the event measured by using front face PMTs depth parameter

Page 19: LXe Beam Test Result

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Correction and selection efficiency

Before depth correction

After depth correctionwith a linear function

Cut-based Qsum analysis

83MeV

55MeV# of events

# of events

In

55 MeV peak

no cut 260k 15k

55 MeV selection with

the other gamma

55k 8129

position selection

15026 1750

depth selection 3018 1362

78 %

Page 20: LXe Beam Test Result

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Energy Resolution

= 1.23 ±0.09 %FWHM=4.8 %

55 MeV

σ = 1.00±0.08 % FWHM=5.2%

83 MeV

Cut-based Qsum analysis

=1.53%

FWHM = 4.5 ± 0.3

=1.16 ± 0.06%

FWHM = 5.0 ± 0.6

CEX 2003 CEX 2004

Page 21: LXe Beam Test Result

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Linear Fit analysisLinear Fit analysis55 MeV event selection55 MeV event selection

Correlation with NaI/LysoCorrelation with NaI/Lyso

83 83 MeV in LXeMeV in LXe

55 55 MeV in LXeMeV in LXe

Y (cm)Y (cm)

X (cm)X (cm)

Small displacement (~ 0.5 cm)Small displacement (~ 0.5 cm)

Linear Fit analysis

In general it is possible to obtain higher In general it is possible to obtain higher efficiency with the linear fit analysisefficiency with the linear fit analysis

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Energy (Linear Fit) and Qsum reconstructionEnergy (Linear Fit) and Qsum reconstruction

Black: Linear FitBlack: Linear FitRed: QSUMRed: QSUMLinear Fit trained Linear Fit trained using MC including using MC including Fresnel reflection; Fresnel reflection; used Q.E. determined used Q.E. determined with six sources. No with six sources. No large differences large differences changing Q.E. set.changing Q.E. set.

The Linear Fit The Linear Fit works better. works better.

No selection, No selection, 600k events600k events NaI cut, NaI cut, 144k events144k events

NaI+sat cut, NaI+sat cut, 83k events83k eventsNaI+sat+coll cut, NaI+sat+coll cut, 54k events54k events

NaI cutNaI cut: : 70 MeV70 MeVQNAIQNAI100 MeV100 MeVColl. cut: Coll. cut: (X(X22 + Y + Y22))1/21/2 4.75 cm 4.75 cm

Linear Fit analysis

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Energy vs. DepthEnergy vs. DepthCorrection along X & YCorrection along X & Y

E (MeV)E (MeV)

Z (cm)Z (cm)

Red: all eventsRed: all events; ; Green: no saturatedGreen: no saturated

Remove ADC saturated events Remove ADC saturated events is equivalent to a depth cut.is equivalent to a depth cut.

Linear Fit analysis

We observed a We observed a slight position slight position dependencedependence of the of the reconstructed reconstructed Energy. Energy.

It can be corrected by using a It can be corrected by using a parabolic interpolationparabolic interpolation..

E (MeV)E (MeV)

E (MeV)E (MeV)

No NeedAnymore

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Saturation &Saturation &NaI cut + R<1.5 NaI cut + R<1.5 cmcm

FWHM = 4.8 %FWHM = 4.8 %

Reconstructed Energy (updated)

Correction (X&Y) effect Correction (X&Y) effect 0.3 % 0.3 %

Linear Fit analysis

83MeV

Saturation &Saturation &NaI cutNaI cut

FWHM = 5.6 %FWHM = 5.6 %

55MeV

Page 25: LXe Beam Test Result

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Position dependence of energy resolution

4.5 0.5 5.1 0.5 6.2 0.8

5.6 0.5 4.9 0.5 4.9 1.1

5.3 0.7 4.9 0.5 5.2 2.0

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Timing Analysis

Intrinsic, L-R analysis

Absolute, Xe-LYSO

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T = TDC - Tref TDC correction for time-walk and position

And correction for position TL, TR by weighted average of Ti

<T> = (TLTR)/2

The algorithm

PMT

i

iii Ni

Q

ctT ,1 ,

/1

/

,

,

1

2,

1

2,,

,

RL

RL

N

iRiL

N

iRiLRiL

RL

TT

i=r.m.s. of Ti

cut on Qi> 50 pe Left

Right

LPNaI S1

LYSO tLP - tLYSO

-

TL

TR

Page 28: LXe Beam Test Result

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Intrinsic resolution, L-R analysis

•Position and Tref

corrections applied

•Applied cuts:

• |x|< 5cm, |y|<5cm

• ELYSO+ENaI >20 MeV

• RF bunch and TDC sat.

•Study of vs Npe

• = 65 ps @ 35000 pe

• = 39 ps @100000 pe

•QE still to be applied

Old data

New data

L-R analysis

Page 29: LXe Beam Test Result

29

Absolute resolution, Time reference (LYSO)

• LYSO PMT1 & 2

• Coorected for x-coord. (not for y)

• Corrections applied for time walk (negligible at high energy deposit)

PMT1 PMT2

Xe- LYSO analysis

LYSO

gamma

slitslit

(TLYSO(R) -TLYSO(L))/2

with 1cm slit

=64 psec

Page 30: LXe Beam Test Result

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Absolute timing, Xe-LYSO analysis55 M

eV

high gainnormal gain

110 psec 103 psec

Xe- LYSO analysis

LYSO Beam L-R depth reso.

110 64 61 = 65 = 56 33 psec

103 64 61 = 53 = 43 31 psec

No

rma

l g

ain

Hig

h

ga

in

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1st look on the waveform data

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DRS Setup

Two DRS chips were available.

10ch/chip (8 for data and 2 for calibration) in total 16 for data

2.5GHz sampling (400ps/sample)

1024 sampling cells Readout 40MHz 12bit Free running domino

wave stopped by trigger from LP

LP Front FaceDRS0 DRS1

Xe()

•DRS inputs•LP: central 12 PMTs•LYSO: 2 anode signals for each DRS chip as time reference

•DRS chip calibration

•Spike structure left even after calibration, which will be fixed by re-programming FPGA on the board.

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Simple Waveform Fitting

Simple function with exponential rise and decay can be nicely fitted to the xenon waveform. (and also LYSO waveform)

Other Fitting functions Gaussian tail

V(t)=A(exp(-((t-t0)/τrise)2)-exp(-((t-t0)/τdecay)2))

CR-RCn shaping V(t)=A((t-t0)/τdecay)n

exp(-(t-t0)/τdecay) Averaged waveform

template

Xenonτrise=7.0nsecτdecay=35nsec

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separation & LYSO timing

Alpha events are clearly discriminated from gamma events. This does not highly depend on the fitting procedure.

LYSO time resolution is similar to that obtained with TDC.

α

γ

Pulse height [mV]

Tim

e co

nst

ant

Pulse shape discriminationLYSO time resolution

Page 35: LXe Beam Test Result

35

Averaged Waveform An averaged waveform can be used

for fitting as a template for simulating pileup for testing analysis algorithm etc.

The measured waveforms are averaged after synchronizing them with T0

Use the “template” for fitting! Pulse shape seems to be fairly constant for the

gamma event.

Average

-40mV -160mV -1200mV

Page 36: LXe Beam Test Result

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Simulation of Pileup Events

Overlapping pulses are simulated using averaged waveform to test rejection algorithm.

Real baseline data obtained by the DRSs is used.

Npe1=2000phe Npe2=1000phe (3000phe is typical for 50MeV gamma)

ΔT=-30nsec

ΔT=+30nsec ΔT=+60nsec

Page 37: LXe Beam Test Result

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Trial of Pileup Rejection

It seems easy to break up overlapping pulses >10ns apart from each other.

Rejection power is being investigated for different sets of (Npe1, Npe2) and ΔT.

Npe1=2000phe Npe2=1000phe

ΔT=-15nsec

ΔT=-10nsec

ΔT=-5nsec

ΔT=+15nsec

Ori

gin

al

Diff

ere

nti

al

easy Difficult but not impossible

?easy

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Cryogenic Equipment Preparation Status

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39

PC150W performance

Condition: 6.7kW(60Hz) 4Hz Twater=20 C (Iwatani 2003.12) 6.0kW(50Hz) 4Hz Twater>30 C (PSI 2004.7)

New PT(190W) andKEK original (65W)

Cool i ng power (PC150)

0

50

100

150

200

50 100 150 200

Col d end temperature(K)

Cooling power (W)

Qi wa(W)Qpsi (W)

at PSI

at Iwatani

Calorimeter operation without LN2 at PSI(Sep.to Oct.2004)42-day operation without degradation in cooling performance

Page 40: LXe Beam Test Result

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Current status/schedule of liquid-phase purification test

xenon

Liquidpump

Purifiercartridge

LP top flange

17/Jan wire installation & closing the cryostat

24/Jan setup in PiE5 -13/Feb evacuation 7-20/Feb liq. N2 piping 14/Feb-13/Mar

liquefaction and test 14/Mar recovery

•New calibration wires with higher intensity•9MeV gamma from Nickel

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End of Slide

Page 42: LXe Beam Test Result

42

The algorithm TDC correction for time-walk and position (point-like approx)

vertex reco. by weighted average of PMTs (new QE set, see Fabrizio Cei’s talk) TL, TR by weighted average of Ti

<T> = (TLTR)/2

/1

/

,

,

1

2,

1

2,,

,

RL

RL

N

iRiL

N

iRiLRiL

RL

TT

i=r.m.s. of Ti

cut on Qi> 50 pe

PMTref

i

iii NiT

c

ind

c

z

Q

wTDCT ,1 ,

),(

Page 43: LXe Beam Test Result

43

The algorithm

T9 F20

= (2905) ps = (345 5) ps

Side PMTs are less sensitive to z-fluctuations than Front PMTs

Page 44: LXe Beam Test Result

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TLXe - TLYSO

Global non-linear corrections for -vertex (50 ps)

mainly due to:

• scale compression (operated by PMT average)

• finite shower size

Page 45: LXe Beam Test Result

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Beam spot on target

Beam profile

• H = 13.2 mm

• V = 9.9 mm

(as measured by Peter)

62.3 ps