TimePix device with silicon sensor
The hybrid silicon pixel device TimePix was
developed at CERN by Medipix collaboration
with support of EUDET project.
It is based on its successful predecessor Medipix2.
The
device consists of a semiconductor detector chip (ussually 300 um thick
silicon)
bump-bonded to a readout chip. The detector chip is equipped with a
single common backside electrode and a front side matrix of electrodes
(256 x 256 square pixels with pitch of 55 um). Each element of the
matrix (pixel) is connected to its respective preamplifier,
discriminator and digital counter integrated on the readout chip. The
noise of analog circuitry is about 650 electrons. Each TimePix pixel
can work in one of three modes:
- Medipix mode - Counter counts incoming particles.
- TimePix mode - Counter works as a timer and measures
time of the particle detection.
- Time over threshold (TOT) mode - Counter is used as
Wilkinson type ADC allowing direct energy measurement in each pixel.
Each individual pixel of the TimePix device in TOT mode is
connected to
its own analog circuitry and AD converter. Thus the device contains
65 536 independent ADCs. All of them have to be individually
calibrated.
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| Pixel
detector Timepix. Device consists
of two chips
connected by bomp-bonding
technique. The upper chip is pixelated semiconductor detector (ussualy
Silicon). The bottom chip is ASIC read-out containing matrix of 256 x
256 of preamplifiers comparators and counters. |
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