Hybrid SiC Pixel Detector for Charged-Particle Beam Monitor

We report on the hybrid silicon carbide (SiC) pixel detector for charged-particle beam monitors in high-energy physics experiments. To demonstrate comparable performances of the state-of-the-art Si pixel detectors, SiC pixel sensors with a die size of
$25 {\mathrm{ mm}}^{2}$
were fabricated based on the p-n diode structure. We combined
$12 \times 12$
diodes of a pixel size of 160 and
$270 ~\mu {\mathrm{ m}}$
pitches with the dedicated readout application-specific integrated circuit (ASIC) by indium and gold (
${\mathrm{ In/Au}}$
) stud-bump technology. The front-end chip was designed in 0.35-
$\mu {\mathrm{ m}}$
complementary metal oxide semiconductor (CMOS) technology, with consideration of a hybrid configuration. Each pixel circuit consists of a charge-sensitive amplifier (CSA) and bandpass filter, optimized for the SiC sensor. The low noise performance achieved an equivalent noise charge (ENC) of 55
$\pm \,\,5{\mathrm{ e}}^{-}$
(rms). The spectrum of
$^{241}{\mathrm{ Am}}$
shows an energy resolution of
${\mathrm{ 1.72 keV}}$
(FWHM) at 17.8-keV
$\gamma $
-rays at room temperature. The obtained image with
$^{90}{\mathrm{ Sr}}$
is a proof of a single minimum ionizing particle (MIP) detection capability with all pixels. Those results prospect a future application of the SiC pixel sensors to high-intensity proton extinction monitors in the coherent muon-to-electron transition (COMET) muon experiment at the Japan proton accelerator research complex (J-PARC).