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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

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LXe Beam Test Result

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Lxe beam test result l.jpg

LXe Beam Test Result

CEX beam test 2004

Cryogenic Equipment Preparation Status

Liquid Xenon Photon Detector Group


Charge exchange beam test at pie5 l.jpg

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


Pmt development summary l.jpg

PMT DevelopmentSummary


Alpha sources on wires l.jpg

Alpha sources on wires

  • 4 tungsten wires plated with Au (50 micron f)

  • 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

wire

LED

gamma


New refrigerator pc150w l.jpg

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


Cex elementary process l.jpg

Eg

170o

q

Eg

Eg

p0

175o

q

54.9MeV

82.9MeV

1.3MeV for q>170o

0.3MeV for q>175o

Eg

CEX Elementary process

  • p-pp0n

    • p0(28MeV/c)  g g

    • 54.9 MeV < E(g) < 82.9 MeV

  • Requiring q>170o

    • FWHM = 1.3 MeV

  • Requiring q > 175o

    • FWHM = 0.3 MeV


Beam test setup l.jpg

Beam Test Setup

H2 target+degrader

LYSO

Eff ~14%

NaI

LP

S1

Eff(S1xLP)~88%

beam


Beam condition l.jpg

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 x108п-/sec

    • Slits 100:    3.95 x108 п - /sec

Optimization of degrader thickness

20mm + 3.3mm x n

Profile at S1, 2mm/bin


Operation status l.jpg

Operation Status

  • Thanks to a new refrigeratorwe 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


Data set l.jpg

Data set

  • And Waveform data…


Analysis result l.jpg

Analysis Result

Calibration

Energy

Timing

1st look on waveform Data


Alpha data l.jpg

Wire (50 μm ϕ)

Alpha

40 μm

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

Po half-life=138 days


Source position reconstruction l.jpg

Source Position Reconstruction

  • The two wires on the front face are a little displaced

LXe

GXe


Alpha data analysis l.jpg

Alpha data analysis

Nphe[0]

Nphe[0] for top-left alpha

with alpha emission angle selection

Center of the PMT-0


Lxe mc absorption length evaluation l.jpg

LXe/MC, absorption length evaluation

4 front sources

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


Q e evaluation with alpha events in liquid l.jpg

Q.E. evaluation with alpha events in liquid

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

Higher light yield  Expected better evaluation if xenon is pure!

R9288

R6041

Data #8528

normal gain

front 4 alphas

MC

reflection on quartz on

no absorption

scattering length :45cm for 175 nm


Energy reconstruction l.jpg

Energy Reconstruction

Cut-based Qsum Analysis

Linear Fit Analysis


Cut based qsum analysis event selection l.jpg

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

Cut-based Qsum analysis

Cut-based Qsum analysisEvent Selection

83 MeV to Xe

55 MeV to Xe

Exenon[nph]

MC


Correction and selection efficiency l.jpg

Cut-based Qsum analysis

Correction and selection efficiency

83MeV

55MeV

Before depth correction

78 %

After depth correction

with a linear function


Energy resolution l.jpg

Cut-based Qsum analysis

Energy Resolution

CEX 2004

CEX 2003

55 MeV

s=1.53%

FWHM = 4.5 ± 0.3

  • = 1.23 ±0.09 %

    FWHM=4.8 %

83 MeV

s=1.16 ± 0.06%

FWHM = 5.0 ± 0.6

σ= 1.00±0.08 %

FWHM=5.2%


Linear fit analysis 55 mev event selection l.jpg

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

Linear Fit analysis

Linear Fit analysis55 MeV event selection

Y (cm)

Correlation with NaI/Lyso

83 MeV in LXe

55 MeV in LXe

X (cm)

Small displacement (~ 0.5 cm)


Energy linear fit and qsum reconstruction l.jpg

Linear Fit analysis

Energy (Linear Fit) and Qsum reconstruction

No selection, 600k events

NaI cut, 144k events

Black: Linear Fit

Red: QSUM

Linear Fit trained using MC including Fresnel reflection; used Q.E. determined with six sources. No large differences changing Q.E. set.

The Linear Fit works better.

NaI+sat cut, 83k events

NaI+sat+coll cut, 54k events

NaI cut: 70 MeV<QNAI<100 MeV

Coll. cut: (X2 + Y2)1/2< 4.75 cm


Energy vs depth correction along x y l.jpg

Linear Fit analysis

Energy vs. DepthCorrection along X & Y

E (MeV)

E (MeV)

E (MeV)

No Need

Anymore

Red: all events; Green: no saturated

We observed a slight position dependence of the reconstructed

Energy.

It can be corrected by using a parabolic interpolation.

Z (cm)

Remove ADC saturated events

is equivalent to a depth cut.


Reconstructed energy updated l.jpg

Linear Fit analysis

Reconstructed Energy (updated)

83MeV

55MeV

Saturation &

NaI cut

FWHM = 5.6 %

Saturation &

NaI cut + R<1.5 cm

FWHM = 4.8 %

Correction (X&Y) effect  0.3 %


Position dependence of energy resolution l.jpg

Position dependence of energy resolution


Timing analysis l.jpg

Timing Analysis

Intrinsic, L-R analysis

Absolute, Xe-LYSO


The algorithm l.jpg

NaI

g

S1

g

LP

LYSO

tLP - tLYSO

The algorithm

p-

  • T = TDC - Tref

  • TDC correction for time-walk and position

  • And correction for position

  • TL, TR by weighted average of Ti

  • <T> = (TLTR)/2

TL

i=r.m.s. of Ti

cut on Qi> 50 pe

Left

Right

g

TR


Intrinsic resolution l r analysis l.jpg

L-R analysis

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 ofsvs Npe

    • s= 65 ps @ 35000 pe

    • s= 39 ps @100000 pe

  • QE still to be applied

Old data

New data


Absolute resolution time reference lyso l.jpg

LYSO PMT1 & 2

Coorected for x-coord. (not for y)

Corrections applied fortime walk (negligible at high energy deposit)

LYSO

slit

slit

gamma

Xe- LYSO analysis

Absolute resolution, Time reference (LYSO)

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

s=64 psec

PMT1

PMT2

with 1cm slit


Absolute timing xe lyso analysis l.jpg

Xe- LYSO analysis

Absolute timing, Xe-LYSO analysis

high gain

normal gain

103 psec

110 psec

55 MeV

Normal gain

High gain


1 st look on the waveform data l.jpg

1st look on the waveform data


Drs setup l.jpg

LP Front Face

DRS0

DRS1

DRS Setup

  • DRS inputs

    • LP: central 12 PMTs

    • LYSO: 2 anode signals for each DRS chip as time reference

  • 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

  • DRS chip calibration

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

Xe(g)


Simple waveform fitting l.jpg

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

τrise=7.0nsec

τdecay=35nsec

Xenon


A g separation lyso timing l.jpg

Time constant

γ

α

Pulse height [mV]

a/g 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.

Pulse shape discrimination

LYSO time resolution


Averaged waveform l.jpg

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

-160mV

-1200mV

-40mV


Simulation of pileup events l.jpg

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=+60nsec

ΔT=-30nsec


Trial of pileup rejection l.jpg

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

Original

ΔT=-10nsec

ΔT=-5nsec

ΔT=-15nsec

ΔT=+15nsec

Differential

?

easy

easy

Difficult but not impossible


Cryogenic equipment preparation status l.jpg

Cryogenic Equipment Preparation Status


Pc150w performance l.jpg

PC150W performance

at Iwatani

  • Condition:

    • 6.7kW(60Hz) 4Hz Twater=20 C (Iwatani 2003.12)

    • 6.0kW(50Hz) 4Hz Twater>30 C (PSI 2004.7)

at PSI

New PT(190W) and

KEK original (65W)

Calorimeter operation without LN2 at PSI(Sep.to Oct.2004)

42-day operation without degradation in cooling performance


Current status schedule of liquid phase purification test l.jpg

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

Current status/schedule of liquid-phase purification test

Purifier

cartridge

Liquid

pump

  • New calibration wires with higher intensity

  • 9MeV gamma from Nickel

LP top flange

xenon


End of slide l.jpg

End of Slide


The algorithm42 l.jpg

The algorithm

  • TDC correctionfor time-walk

    and position (point-like approx)

    vertex reco. by weighted average of PMTs

    (new QE set, see Fabrizio Cei’s talk)

  • TL, TRby weighted average of Ti

  • <T> = (TLTR)/2

i=r.m.s. of Ti

cut on Qi> 50 pe


The algorithm43 l.jpg

The algorithm

T9

F20

s = (2905) ps

s = (345 5) ps

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


T lxe t lyso l.jpg

TLXe - TLYSO

  • Global non-linear corrections for g-vertex (50 ps)

  • mainly due to:

  • scale compression (operated by PMT average)

  • finite shower size


Beam spot on target l.jpg

Beam spot on target

  • Beam profile

  • sH = 13.2 mm

  • sV = 9.9 mm

  • (as measured by Peter)

  • sp = 62.3 ps


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