Ⅱ-9. Instrumentation

RIKEN Accel. Prog. Rep. 51 (2018)

Overview of silicon strip sensor detector developmentfor sPHENIX experiment
I. Nakagawa,∗1 Y. Akiba,∗1 D. Cacace,∗2 E. Desmond,∗2 T. Hachiya,∗2,∗3 Y. Kawashima,∗1,∗4 E. Mannel,∗2H. Masuda,∗1,∗4 G. Mitsuka,∗1 R. Nouicer,∗2 R. Pisani,∗2 K. Shiina,∗1,∗4 M. Tsuruta,∗1,∗4 and Y. Yamaguchi∗1Fig. 2. The INTT ladder prototype for layers 1 to 3. The
ladder consisted of silicon sensors, FPHX readout chips
used for former silicon detector in the PHENIX experiment, a high density interconnect (HDI) readout cableand a support structure.

Beam Pipe

INTT4 layers



The intermediate tracker (INTT)1,2) is a barrel type
tracker to be implemented outside of another tracking
device MVTX detector near the beam pipe and covering central rapidity region of the sPHENIX collision
point as shown in Fig. 1. The development of INTT isnow in the second generation prototype testing stage.
Shown in Fig. 2 is the INTT ladder prototype for layers 1 to 3. Various response tests have been executedand resulting performances are found to be satisfactory.3) Further tests will be performed using cosmic
rays in the test bench. An external trigger using scintillators is under development for the measurement.4)
These prototypes are to be tested with a beam at Fermilab in March, 2018. A three-layer telescope setup isunder preparation for the beam test. In parallel, thethird generation silicon sensors for the layers 1 to 3 arealready under manufacture and they are expected tobe the pre-production version.

 MVTXFig. 3. R&D schedule of INTT.

Fig. 1. Layout of inner tracking systems of the sPHENIXexperiment. The beam pipe is lapped with 3 layers ofMVTX and 4 layers of INTT detectors.

The study was made to optimize the design of thelayer-0.7) Due to the closest distance from the collision
point, the layer-0 is designed to reduce its channel occupancy of the detector by charged particles as muchas possible. As shown in Fig. 3, the ﬁrst prototype forthe layer-0 silicon and the high density interconnect(HDI) readout cable have been manufactured and tobe tested in spring of 2018. The HDI of layer-0 is designed to be narrower than that of layers 1 to 3 sincenumber of signal lines are fewer.
The biggest technical challenge in the R&D pro∗1
∗2
∗3
∗4

RIKEN Nishina Center
Brookhaven National Laboratory
Nara Woman’s University
Department of Physics, Rikkyo University- 160 -

cess of the INTT is a design of its bus extender cable. Due to the requirement of long signal transmission(∼ 1.3 m) within a limited space, standard ﬂat ﬂexible cables can not be used. A development of a highdensity multi-layered ﬂexible cable have started eﬀectively in spring of 2017.5) One of key developments is
to make the diﬀerential signal line width as narrow as
possible and achieve the higher density in order to satisfy the compactness of the cable. We are about to
get to the latest technology limit of the line width for
1.3 m distance.
References
1) I. Nakagawa et al., Accel. Prog. Rep. 48, (2015).
2) I. Nakagawa et al., Accel. Prog. Rep. 49, 106 (2016).
3) H. Masuda, in this report.
4) K. Shiina, in this report.
5) T. Hachiya, in this report.
6) M. Tsuruta, in this report.
7) Y. Yamaguchi, in this report.