Ⅱ-9. Instrumentation

RIKEN Accel. Prog. Rep. 49 (2016)

Frame design for the γ-ray detector array CATANA
N. Chiga,∗1 H. Otsu,∗1 M. Shikata,∗1,∗2 T. Ozaki,∗1,∗2 A. T. Saito,∗1,∗2 T. Nakamura,∗1,∗2 Y. Kondo,∗1,∗2 andY. Togano∗1,∗2The γ-ray detector array CATANA1) is being constructed to measure the E1 response of the neutronrich nuclei. 200 CsI(Na) detectors compose CATANA,
and are conﬁgured the packed layout (barrel shape) torealize the high detection eﬃciency and position resolution. This report describes the design of the CATANAframe and its concepts.
Since CATANA will be used in many experimentswith SAMURAI, The frame should have the highmaintainability and ﬂexibility. The CsI(Na) crystals
will be conﬁgured to have a barrel like structure (CsIunit) to achieve the high eﬃciency as shown in the left
side of Fig. 1. To achieve the high maintainability,
the 10 detectors will be supported by a frame shownin the right side of Fig. 1 , and the barrel like conﬁguration will be realized by using 20 CsI units. TheCsI(Na) crystal and PMT are connected by using aninlaid support on the top of the crystal. An O-ring isput for light shielding between the inlaid support andthe crystal. The detector is connected to the CsI unit
by a jig. Individual detector can be easily removed
from the CsI unit, for the high maintainability. Fine
adjustment of the detector positions can be done on
the CsI unit. The total weight of the CsI unit is about
25 kg so as to handle it without a crane operation. A
side plate of CsI unit has numerous small holes for theeasy and clean cabling.
Figure 2 shows the main frame of the CATANA(left) and half of the top part (right). The CsI unit
is mounted on the main frame by a guide attached tothe main frame. The guide is made of a synthetic resin
to isolate the CsI unit electrically. The frame widthalong the beam line and the frame height are 59 cm
and 276 cm, respectively. The width is almost halfof the present DALI frame2) , so as to put a reaction
target closer to the SAMURAI magnet. The wholeframe can be craned by using eyebolts on the mainframe. The top part of the main frame can be opened
to the direction perpendicular to the beam line for easier work around the reaction target put at the centerof CATANA. The shaft for the opening is a trapezoidal
screw to ﬁx the position of the frame without any locking mechanism. Ladders for cables are put on a plate
to support the CsI unit (shown in purple in Fig. 2).
The bottom part of the main frame has space at bothsides to put a high-voltage power supply for PMTs
and/or circuits for signal processing. The space follows the EIA standard for 19-inch racks. The parts forseismic reinforcement are put under the main frame.
∗1∗2RIKEN Nishina Center
Department of Physics, Tokyo Institute of Technology- 166 -The oﬀsets of heights can also be attached under themain frame, to cope with the diﬀerent beam-line height
depending on the focal planes such as F8 of BigRIPS.
The CATANA frame construction is now in progress.

Beam

Fig. 1. Configuration of CsI(Na) detectors in CATANA(left) and the support frame for 10 detectors (right).

Beam

Fig. 2. The frame of CATANA with 200 CsI(Na) crystals.

References
1) Y. Togano et al.: RIKEN. Accel. Prog. Rep. 47, 179(2013).
2) S. Takeuchi et al.: Nucl. Instr. and Meth. A 763, 596(2014).