Ⅱ-9. Instrumentation

RIKEN Accel. Prog. Rep. 50 (2017)

Sensor module prototype for Silicon INTT for sPHENIX
Y. Akiba,∗1 T. Hachiya,∗1 Y. Kawashima,∗1∗2 E. Mannel,∗3 H. Masuda,∗1∗2 G. Mitsuka,∗1 I. Nakagawa,∗1
D. Nemoto,∗1∗2 R. Nouicer,∗3 and Y. Yamaguchi∗1
We are developing a new silicon intermediate tracker
1)2)
for sPHENIX,sPHENIX, aa new
new experiment at the RelINTT1,2)
forativistic Heavy Ion Collider at Brookhaven NationalLaboratory. In this article we report on the researchand development of the silicon module of the INTT.

Fig. 2. Part of the sensor design drawings made by HPK.
Fig. 1. Conceptual design of the sensor module for layers
1 to 3 of the INTT detector.

Figure 1 illustrates the conceptual design of thesensor module for layers 1 to 3 of the INTT detector. The module consists of two pieces of silicon sensors, named type-A and type-B, and 26 read-out chips(FPHX chips) placed on a fexlible circuit board called
high-density interconnect (HDI).
The sensors are single sided, AC coupled sensors.
The active area of the type-A and type-B sensors are
128 mm × 19.96 mm and 100 mm × 19.96 mm, respectively. The active area of the type-A (type-B) sensor
is divided into 8 × 2 (5 × 2) blocks. Each block has 128
short strips that are 78 μm in pitch and 16.0 mm (typeA) or 20 mm (type-B) long, and run parallel to the z(beam) direction. In Fig. 1, the strip runs horizontally.
The read-out lines of the strips run perpendicular tothe strips and bring the signals to the read-out chips
placed on the HDI at the upper and lower edge of thesensor.
FPHX chips, which were used for the Forward VerTeX (FVTX) silicon tracker of PHENIX, are utilized
to read out the sensor. An FPHX chip has 128 channels of 3 bit ADCs and it can read out 128 mini-strips
in one block of the sensor. The read-out pad pitch of
the sensor is thus matched to that of the FPHX chip
(75 μm). The FPHX chip has a low power consumption of about 64 mW per chip, which reduces the needfor cooling the sensor module. The analog signal ofeach strip is digitized in the FPHX chip, and the digitized data of 128 channels are sent out through the200 MHz data-out port of the FPHX chip.
The HDI is a 7 layer ﬂexible circuit board used to∗1
∗2
∗3

read out these two sensors. One type-A and one type-B
sensor and 26 FPHX chips are placed on an HDI. The
type-A (type-B) sensor is read out by 16 (10) FPHX
chips: 8 (5) at the upper edge and 8 (5) at the lower
edge of the sensor. The data from the FPHX chips aresent to the front end module though the high speed
data bus in the HDI.
The sensors will be manufactured by Hamamatsu
Photonics Co. (HPK). Fig. 2 shows a part of the design
drawings of the sensor made by HPK.
We will produce both type-A and type-B sensors
with two thicknesses. One is 320-μm thick, which isthe standard thickness of wafers that HPK uses. The
other is 200-μm thick, which is made by thinining the320 μm sensors. The thinner sensor results in lower
scattering of charged particles and thus improves themomentum resolution of tracks. However, the signal
generated by a hit will be reduced. We will evaluate theS/N ratio for MIP particles for both types of sensors
to determine which one we will use for the production.
The design of the sensor at HPK has been completed
and they are manufacturing the sensors. We expect thedelivery of the sensors by early 2017.
The HDI will be manufactured by Yamashita Co.
They will be delivered by early 2017.
The sensors and HDIs are assembed into sensor modules at Brookhaven National Laboratory, where they
will be tested with a test bench.
References
1) I. Nakagawa: In this report.
2) Y. Yamaguchi: In this report.

RIKEN Nishina Center
Department of Physics, Rikkyo University
Brookhaven National Laboratory- 221 -