bogdan wojtsekhowskihallaweb.jlab.org/experiment/apex/documents/scifi_12... · 2014. 12. 4. ·...
TRANSCRIPT
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December 4, 2014 Bogdan Wojtsekhowski, APEX
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Specialized APEX hardware update
Bogdan Wojtsekhowski
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December 4, 2014 Bogdan Wojtsekhowski, APEX
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Specialized APEX hardware: Septa magnet
HRS right
HRS left
.
Positron, P = E0/2
Electron, P = E0/2
Septum
10 high Z thin targets
Beam
.
Septa works well for Δp/p
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December 4, 2014 Bogdan Wojtsekhowski, APEX
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By, Gauss
External shield
Inner shield
5 deg. trajectory passes here
Permendur
Field vs. distance from the beam, ���in the septa middle plane
Specialized APEX hardware: Septa magnet
beam at x =0
trajectories to HRS from 4 to 6 deg.
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December 4, 2014 Bogdan Wojtsekhowski, APEX
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Magnet view and correctors
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December 4, 2014 Bogdan Wojtsekhowski, APEX
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Magnet top view and vacuum connections
SciFi
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December 4, 2014 Bogdan Wojtsekhowski, APEX
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Specialized APEX detector: SciFi detector
Traditional sieve pattern
7"""""""0.000
8"""""""0.271
9"""""""0.524
10"""""""0.784
11"""""""1.037
12"""""""1.309
13"""""""1.559
14"""""""1.825
6""""""-0.238
5""""""-0.510
4""""""-0.760
3""""""-1.032
2""""""-1.282
1""""""-1.538
0""""""-1.788
0""""""0.646
1""""""0.549
5""""""0.000
4""""""0.181
3""""""0.279
2""""""0.365
6"""""-0
.096
7"""""-0
.242
8"""""-0
.481
9"""""-0
.596
10"""""-0
.715
11"""""-0
.830
7"""""""0.000
8"""""""0.259
9"""""""0.522
10"""""""0.778
11"""""""1.044
12"""""""1.306
13"""""""1.556
14"""""""1.819
6""""""-0.253
5""""""-0.519
4""""""-0.775
3""""""-1.031
2""""""-1.288
1""""""-1.544
0""""""-1.803
0""""""0.837
1""""""0.716
5""""""0.095
4""""""0.237
3""""""0.476
2""""""0.599
6""""""0.000
7"""""-0
.235
8"""""-0
.283
9"""""-0
.368
10"""""-0
.555
11"""""-0
.650
Sieve"Hole"Position"Measurement"(inches)
Left%Sieve Right%Sieve
x-plane
z0 50 5 1010 1515 2020
-6-6
-4-4
-2-2
0
2
4
6
8
1010
1212
y-plane
z0 50 5 1010 1515 2020
-4-4
-2-2
0
2
4
6
8
Q1 Q2 Q3DipolDipole
Q1 Q2 DipolDipole Q3
[m]
[m]
[m]
[m]
Tracker
VDCs
Target
Spectrometer optics
Sieve
Calibrated optics is good to 0.1 mrad!
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December 4, 2014 Bogdan Wojtsekhowski, APEX
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Specialized APEX detector: SciFi detector
Active “sieve slit”: a Sci Fiber detector with
1 mm fibers with 1/4” pitch connected via a bundle of 1.5 mm clear fibers to a 64-channel PMT.
Readout via 1877S TDC; 1-3 MHz rate per fiber; off-line time window of < 5 ns
Traditional sieve pattern
Positively
charged particle
optics needs
the SciFi
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December 4, 2014 Bogdan Wojtsekhowski, APEX
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Specialized APEX detector: SciFi detector
Active “sieve slit”: a Sci Fiber detector with
1 mm fibers with 1/4” pitch connected via a bundle of 1.5 mm clear fibers to a 64-channel PMT.
Readout via 1877S TDC; 1-3 MHz rate per fiber; off-line time window of < 5 ns
The front-end is made with the low threshold A/D card from MWDC.
Tested in September – a significant rate of hits
in the DAQ is due to crosstalk signals: capacitive coupling between adjacent electronic channels.
It limits the range of PMT HV and efficiency.
Traditional sieve pattern
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December 4, 2014 Bogdan Wojtsekhowski, APEX
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Specialized APEX detector: SciFi detector
Active “sieve slit”: a Sci Fiber detector with
1 mm fibers with 1/4” pitch connected via a bundle of 1.5 mm clear fibers to a 64-channel PMT.
Readout via costly VME fADC250: 4 ns ticks; allow up to 20 MHz rate per fiber; off-line time window of ~ 5 ns, integration window just 12 ns
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December 4, 2014 Bogdan Wojtsekhowski, APEX
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Specialized APEX detector: SciFi detector
The front-end is a fast NIM amplifier.
Preliminary tested in November – works!
Require more studies with additional
analysis scripts.
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December 4, 2014 Bogdan Wojtsekhowski, APEX
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pixel #
the main pulse in pixel #7
crosstalk in pixel #6
crosstalk in pixel #8
trigger signal
the dinode
16 ns
20 ns
12 ns
8 ns
4 ns
0 ns