Upload
wheatley-hamza
View
30
Download
1
Embed Size (px)
DESCRIPTION
Liquid Xenon Detector Part I. CEX beam test at piE1 Oct-Dec/03 Hardware operation status Analysis A. Baldini’s presentation Other related topics Detector Calibration PMT R&D A. Baldini’s presentation Refrigerator Liquid phase purification Cryostat Liquid Xenon Detector Group. - PowerPoint PPT Presentation
Citation preview
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Liquid Xenon DetectorPart I
• CEX beam test at piE1 Oct-Dec/03– Hardware operation status
– Analysis A. Baldini’s presentation
• Other related topics– Detector Calibration
– PMT R&D A. Baldini’s presentation
– Refrigerator
– Liquid phase purification
– Cryostat
Liquid Xenon Detector Group
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Large PrototypeLarge Prototype• 70 liter active volume (120 liter LXe in us
e), 228 PMTs• Development of purification system for xe
non• Total system check in a realistic operating
condition:– Monitoring/controlling systems
• Sensors, liquid N2 flow control, refrigerator operation, etc.
– Components such as• Feedthrough,support structure for the PMTs,
HV/signal connectors etc.
– PMT long term operation at low temperature
• Performance test using– 10, 20, 40MeV Compton beam– 60MeV Electron beam– from 0 decay
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
CEX beam test at piE1
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Elementary process
- (essentially) at rest captured on protons:
- p 0 n - p n
0
Photon spectrum
54.9 82.9 129MeV
M/2
M/2(1cos*)
M/2
*
E=55 MeV * =
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Angular selection -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
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Overview of the beam test
• 25/Sep Detector was moved to the area. evacuation
• 27/Sep- Beam tuning• 29/Sep pre-cooling• 2/Oct-5/Oct Liquefaction• 5/Oct-29/Oct Purification(gas phase)• 5/Oct- Electronics setup• 15/Oct 0 detected• 24/Oct empty target run• 1/Dec PMT amplifier study• 6/Dec Recovery• 7/Dec Cold xenon gas data for PMT
calibration
22/Sep
29/Sep
6/Oct
13/Oct
20/Oct
27/Oct
3/Nov
10/Nov
17/Nov
24/Nov
1/Dec
8/Dec
0 detected
Beam tuning
purification
pumping
Cooling/liquefaction
DAQ
~7weeks
Recovery Cold xenon gas data
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
• Beam line– Magic momentum (110MeV/c)– FSH52, 4mm carbon degrader (110
107MeV/c) in ASY51– 26mm carbon degrader in front of t
he target– S1 counter (40x40x5mm3) to defin
e the beam
• Area layout– The Electronics barrack placed in th
e area with concrete shielding around it.
– All controls and monitors done in the barrack.
– Liquid nitrogen supplied from a dewar located in the area.
E1 beam line
Proton beamTarget
ASY51
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Setup
Carbon degrader
Lead Collimator at the beam line exit
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Hydrogen Target
• Thanks to Dr. J. Zmeskal.
• Liquid H2 cooled with a GM-refrigerator
• Temperature control
• Target cell– 0.5mm t Al
– 40mm d x 100 L
– 125cc liquid hydrogen
• Kapton foil– entrance
– exit
cell
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
NaI detector
• For tagging at the opposite side of LP 8x8 NaI crystals– 40.6x6.3x6.3cm3
• Located 110cm from the target
• Signal processor and Trigger Box (QUAD module) to provide trigger signal
A
B
C
D
E
F
G
H
8 7 6 5 4 3 2 1
For trigger
For trigger
Base Line
Stabilizer
Attenuator
x10
x10
ADC
Trigger
Box
TDC
Crystal Array
HV
Trigger module
Differential input stage
Differentiator, Attenuator and base line stabilizer
Output stage
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
NaICalibration
High voltage value for each PMT is adjusted by using cosmic ray events.
Pedestal subtraction & Gain correction are done in the offline analysis.
Energy and Vertex reconstruction are performed by using corrected charge information next slides.
Cosmic ray events HV adjust & Gain Correction
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
NaIEnergy Estimation
Search for the NaI crystal with maximum charge
Charge sum in the surrounding NaI’s.
The Calibration parameter is determined by using 129MeV data. ( 37MeV/cosmic peak )
Raw Sum
NaI with MaxQ
Reconstructed Energy
55MeV
83MeV
threshold
129MeV
• - p 0 n
0
(E = 55, 83MeV)
• - p n
(E = 129MeV)
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
NaIEnergy Resolution
• 55 MeV 7.0+/-0.13 %
• 83 MeV 6.5+/-0.14%
• 129 MeV 6.1+/-0.04%
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
NaIVertex Reconstruction
Search for the NaI with maximum charge
Fit the charge distribution of the raw or column (8 NaIs in each) that include NaI with maximum charge using a gaussian function.
4cm diam. collimator.
NaI with MaxQ
x 2.7cmy 1.6cm
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
- stopping distribution in the target must be considered in subtraction
Timing Counter• 2 layers of
– 5cm x 5cm x 1cm BC404– Hamamatsu R5505 at both ends– 3mm t Pb plate
• Time resolution can be estimated internally by TC1-TC2
5cm x 5cm x 1cm t
BC404
R5505
Viewed from the target
100mm
Lead collimator
TC
LPNaI S1
TCtLP - tTC
Pb
!
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Timing Counterefficiency and resolution
• ~40% efficiency for 83MeV (> 1MeV deposit in the scinti.)
• 60 psec time resolution in sigma
55MeV
83MeV
129MeV
GEANT simulation
Ratio of events with > 1MeV deposit in the scintillator
(TC1-TC2)/2
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Xenon Large Prototypeoperating condition
• Gain/QE calibration– LED and as usual
• PMT gain 106, 5x106
• Absorption length after 2 weeks purification abs > 140cm (90% C.L.)
(central value ~2.7m)
• Xenon extracted from the chamber is purified by passing through the getter.
• Purified xenon is returned to the chamber and liquefied again.
• Circulation speed 5-6cc/minute
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
QE Calibration
The peak position is well reproduced by this MC code.
• Gas xenon data had been used for calibration because the absorption can be ignored in gas. – W-values are equivalent in gas and liquid?
• Established purification scheme provided very pure xenon.– Possible to evaluate PMT QE’s using the event.
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Data Acquisition
• Hardware setup– ADC 3 ranges for front-face PMTs
2 ranges for the others– TDC for all PMTs– PMT amplifier (x10)
• BINP• Lecce
• Software– Online MIDAS– Slow control (MSCB+LabView)
• Refrigerator control, Temp., Pressure Monitor
• Data set– Collimators in front of LP and NaI
( back to back)– Timing Counter (Pb+Scintillator) i
n front of NaI
Preamplifier Module
Av = 1
-In
+In
300
15050
CLC449
Av = +1
300
300
CLC44950
50
Av = -10
Discrete transistors
50
Av = +1
AD8001
32 Channels
8 units
Full-bandwidth Outs
Full-bandwidth Outs
Low range (x8 amplification)
Middle range
High range (20dB attenuation)
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Trigger
• back-to-back data– NaI : sum signal of the central 4 crystals– LP: sum signal of
• 8 PMTs on the front face & 4 PMTs on the back face
• data with opening angle < 180o
– NaI : QUAD module
• Very low threshold trigger for LP– One or two hit(s) in any one of 8 clusters
• , LED, cosmic-ray, pedestal triggers for calibration
123
4
5
6
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Beam Condition• p(-)=107MeV/c
– Almost maximum separation (8nsec) of arrival time to the target between and , and between and e.
• Beam intensity– Up to 2.6 MHz @ 1800A
• Electron contamination in the beam– Negligible in triggered events
targetx=12mm
y=12mm
e/
~8nsec
TOF separation
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
0 signal example
LP ADC
NaI
AD
C
LP 83 MeV
NaI 55 MeV
LP 55 MeV
NaI 83 MeV
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Background Condition• Background events
– most probably caused by beam-related neutrons,
– Energy deposit up to 9-10MeV,
– Corresponding to 1.5x106 p.e./sec
• Beam on/off– PMT output for events changes, reduced to 70%
of normal values at full intensity beam rate (less reduction at lower intensity)
• Not due to bleeder current shortage but due to photocathode saturation because we observed the same effect even with lower PMT gain.
events/ beam off
events/ beam on
Thermal neutron in Xe
•Absorption length ~ 3 cm• Capture close to calorimeter walls• Multi γ, ΣE(γ) = 9.3 MeV
PMTs used in LP do not have Al strip
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Pulse Tube Refrigerator
1. Heat load and PT cryocooler 2. Further test and schedule
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
- Heat Load -
Heat LoadW@165K
Phase LXe(L)
PMT
Static PMT Cable
Total(W)
L.Proto 120 250 24 16 10 50Final 800 1000 20 65 45 130
-Based on the KEK-original PT cryocooler, Cryocooler with higher cooling power has been developed for the final calorimeter
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Technology transfered to
Iwatani Co., Ltd
Designed:
150 W @165K
Large Power Pulse Tube Cryocooler
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Large Power Pulse Tube Cryocooler
One for Columbia University
For Dark Matter SearchDesigned:
90 W@165K
3kWcompressor
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Large Power Pulse Tube Cryocooler
Technology transfered to
Iwatani Co., Ltd.
Two for MEG
Designed:
150 W @165K
using 6.7kW compressor
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Large Power PT Cryocooler-Cooling power at 6.7kW compressor-
PT150 Cooling Power
0
50
100
150
200
250
60 80 100 120 140 160 180 200
Temperature (K)
Cool
ing
Pow
er (
W)
Q150 (W)
Qkek(W)
KEK originalfor Large Proto
For final calorimeter6.7kW, 4Hz
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Results and Further Tests
-Achieved cooling power of 190W at 165K (6.7kW compressor)
-Orientation dependence test... Horizontal layout for the case of two cold head-Another phase shift configuration (Double Inlet) test... To increase cooling power
Schedule
-January 2004: Final parameter fixed-February 2004: Fabrication will start-March 2004: Will be delivered (two sets)-Can be installed for the LXe liquid purification test
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Liquid Phase Purification
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Liquid phase purification test
• Pump and purifier in the Large Prototype chamber– Very simple
– No worry about heat load
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Implementation in the final detector
• Xenon from the bottom bypass the wall to the pump/purifier
• Easy maintenance
• Possible heat load to the bottom
Next slide
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Realization of the system
• Verification of liquid phase purification– Large Prototype is the
best to show the purification performance
• Long term operation in the final detector– Heat load to the bottom
must be minimized
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Purification systemin the final detector
LXe CalorimeterLiquid circulating purifier
Liquid pump (100L/h)
Purifier1000L storage dewar
Cryocooler (100W)
LN2
LN2
Getter+Oxysorb
GXe pump (10-50L/min)
GXe storage tank
Cryocooler (150W)
Heat exchanger
Gas phase purification
Liquid Phase purification
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Status• Fluid pump was delivered to a Japanese manufacturer.
• Assembling the pump and purifier cartridge for verification.
• The system will be tested using the LP.
motor
Outside of the cryostat
(room temp.)
Inside of the cryostat
(low temp.)
Impeller
Pump isolator
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Cryostat Construction
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Design goals:
-Design goals:-Independent test of the inner vessel and outer vessel during construction.-Implementation of a draining system.-A simplification of the supporting system (three legs.) and a limiting displacement system-Adding a pre-cooling system on the inner vessel covers.-Adding a safety valve on the outer vessel for positive pressure.-Adding a rohacell sheet between the outer thin window and the magnet structure for positive pressure.
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
-Problem with high strength austenitic stainless steel.-To obtain high yield we need a stress hardening process that causes a slight ferromagnetic characteristic that can be removed by a special heat treatment.-Size of the sheet can be another problem.-The austenitic ss with the nitrogen should have a better strength and a better magnetic characteristic.
Windows material
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Thickness of the Walls/Covers
• Suppose the pressure tolerance of 0.3MPa for the inner vessel and 0.1MPa for the outer vessel (vacuum insulation layer).
Walls/Cover Material DimensionPressureDirection
Design PressureMPa
Design Tempdegree C
ThicknessCalculation (mm)
Thickness Actual(mm)
Inner Vessel Inner Wall SUS316L R623 x L1086 Outer 0.3 -108~40 5.4 7.0Inner Vessel Outer Wall SUS316L R1116 x L1086 Inner 0.3 -108~40 3.0 7.0
Inner Vessel Front Wall SUS316L min504 x max1086 Inner 0.3 -108~40 23.0 24.0Inner Vessel Cover SUS316L R1148 x R588 Inner 0.3 -108~40 22.7 24.0
Outer Vessel Inner Wall SUS316L R550 x L1260 Inner 0.1 40.0 0.5 0.5Outer Vessel Outer Wall SUS316L R1200 x L1270 Outer 0.1 40.0 7.5 8.0Outer Vessel Front Wall SUS316L min650 x max1270 Outer 0.1 40.0 16.7 20.0Outer Vessel Cover SUS316L R1200 x R540 Outer 0.1 40.0 15.4 20.0
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Heat Load Calculation
• See also T. Haruyama’s talk on Jul 2002 review meeting.
• Main contribution is from PMT and cables.
• One pulse tube refrigerator can compensate the load.
• Possibility of mounting two refrigerator is now investigated
Heat load calcluation for the xenon photon detector vessel
UnitRadiation Outer Vessel -> Inner Vessel (30 Mylar layers) 3.1 WConduction Nozzle (N1-N3) via xenon gas 0.2 WConduction Nozzle (N1-N3) via belows 4.6 WConduction Support (brace and supporting pipe) 6.3 WHeat generation PMT (65mW/PMT) 52 WConduction PMT HV and Signal Cables 50 Wtotal 116.2 W
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Several modifications from the previous design
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Photon Detector
2002 2003 2004 2005
Test MilestoneAssemblyDesign Manufactoring
Large Prototype Beam Test Beam Test
Vessel Design Assembly & Test
PMT Delivery + Testing
Refrigerator Manufactoring Assembly
Liq. Purification
Assembly Test
Manufactoring
Engineering runs
Liquid Xenon Photon Detector Feb. 2004 MEG Review Meeting
Summary
• CEX beam test was carried out at E1 area.– Analysis Results A. Baldini’s presentation
• Liquid Phase Purification test will be done in 2004.
• Refrigerator will be assembled and delivered soon.• Cryostat design renewal.• Plan in 2004
– LP operation in E5 to see background condition and COBRA magnetic field effect.