II-9. Instrumentation

RIKEN Accel. Prog. Rep. 55 (2022)

RIKEN Accel. Prog. Rep. 55 (2022)

Test beam experiment at ELPH in Tohoku University
for sPHENIX INTT
G. Nukazuka,∗1 Y. Akiba,∗1 D. Cacace,∗2 H. En’yo,∗1 K. Cheng,∗3 T. Hachiya,∗1,∗4 S. Hasegawa,∗1,∗5M. Hata,∗4 H. Imai,∗1,∗6 T. Kondo,∗7 C. Kuo,∗3 H. -S. Li,∗8 R. -S. Lu,∗9 E. Mannel,∗2 C. Miraval,∗2
M. Morita,∗1,∗4 I. Nakagawa,∗1 Y. Nakamura,∗1,6 G. Nakano,∗1,∗6 Y. Namimoto,∗1,∗4 R. Nouicer,∗2 R. Pisani,∗2M. Shibata,∗1,∗4 M. Shimomura,∗4 C. Shih,∗3 M. Stojanovic,∗7 Y. Sugiyama,∗4 R. Takahama,∗1,∗4W. -C. Tang,∗3 K. Toho,∗10 K. Tsuruta,∗10 M. Watanabe,∗4 and X. Wei∗8∗1RIKEN Nishina Center
Physics Department, Brookhaven National Laboratory∗3 Department of Physics, National Central University∗4 Department of Mathematical and Physical Sciences, Nara
Women’s University∗5 Japan Atomic Energy Agency∗6 Department of Physics, Rikkyo University∗7 Tokyo Metropolitan Industrial Technology Research Institute∗8 Department of Physics and Astronomy, Purdue University∗9 Department of Physics, National Taiwan University∗10 Laboratory for Nuclear Science, Tohoku University∗2- 100 -PMT Trigger Sci.

INTT ladder-3

INTT ladder-2

INTT ladder-1

INTT ladder-0

PMT Trigger Sci.

Dark box

Additional
Lead Platee+ beam
1 GeV

PMT

FingertipSci.

box containing four INTT ladders, which have 6656
strips in the active area of about 465.5×20.0 mm2 , wasset on the beamline, and two plastic scintillators wereplaced upstream and downstream as external triggers(Fig. 1). Depending on the trigger and veto conﬁgurations, the trigger rate was up to 100 Hz. Three ofthe ladders could take hit data successfully. A readoutcard acquires hit information from the ladders, and theDAQ stores hit coincidences with the external trigger
signal. A ﬁngertip scintillator was installed additionally to restrict the position of the hits in analysis.

NIM logic circuit
CAMAC DAQ

Readout Card

External
Trigger Input
INTT Signal Processes
External Trigger Processes

DAQ PC

Fig. 1. Schematic diagram of the setup.

Data acquisition for about 50 h, divided into 65 runs,
collected about 4 × 107 hits (Fig. 2). A hit map ofladder-1 with a typical setup (Fig. 3) shows the beam
proﬁle clearly. Data analysis is currently ongoing, andpreliminary results for the detection eﬃciency are discussed in this report.5)

Sum of thecllected hits

The sPHENIX1) collaboration will start data acquisition from 2023 to study quark-gluon plasma and cold
quantum chromodynamics at the Relativistic Heavy
Ion Collider (RHIC) in Brookhaven National Laboratory. The intermediate silicon tracker (INTT),2) one of
the tracking detectors in the sPHENIX detector complex, plays a crucial role in tracking and jet ﬂavor tagging with high precision and low background. Fifty-six
INTT ladders with about 370 thousand silicon strips
in total form a double-layer barrel to surround the interaction point. The position and timing resolutions of
the prototype showed satisfactory performance in theprevious experiment at Fermilab in 2019. Although adetection eﬃciency of 100% is expected owing to its
high sensitivity to ionizing radiation, a detection efﬁciency about 96% was obtained in the experiment.3)
An internal clock of 9.4 MHz (beam clock, BCO) in thesystem drove the INTT while the signals synchronizedwith the beam collision drove at RHIC. The timing
mismatch of the BCO and the beam may explain theinsuﬃcient detection eﬃciency. The insuﬃcient detection eﬃciency in the experiment may be due to theunsynchronized operation of INTT with the test beam.
We performed a test beam experiment in December
2021 to test the hypothesis and perform the following:• Tests and performance evaluation of the massproduction ladders• Tests of the long readout extension cable of 1.2 m4)• Analog-digital converter distribution measurements with various beam injection angles with respect to the INTT ladders• Performance evaluation of the ladders in a multitrack condition similar to that in RHIC by installing a lead plate the upstream of the setup
We measured hits on INTT ladders with a positron
beam of 1 GeV at the Research Center for Electron
Photon Science (ELPH) in Tohoku University. A dark

5E+07
4E+07
3E+07
2E+07
1E+07
0E+00
2030

40

50

60

70

80

90RunFig. 2. Sum of the collected hits on the INTT ladders.

1II-9. Instrumentation

RIKEN Accel. Prog. Rep. 55 (2022)

Fig. 3. Hit map of ladder-1.

References
1) A. Adare et al., sPHENIX proposal (2015).
2) I. Nakagawa et al., in this report.
3) A. Suzuki, Master thesis, Nara Women’s University(2020).
4) T. Hachiya et al., in this report.
5) M. Morita et al., in this report.

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