HELIX_128_2.2
irradiation
-
One HELIX 128 chip in the AMS 0.8u CMOS technology, has been
irradiated at NMI in Utrecht Netherlands.
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The irradiation came from a 7krad/hour Co 60 source. The
irradiated area was 2 x 2 cm.
-
The chip is irradiated in 2 steps of about 100kRad
during the weekend, and then measured in the next week.
Document discribing the irradiation
of the HELIX2.2 chips, written by Jaap Velthuis : radtest.ps
.
Helix bias settings:
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Ipre 80
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Isha =Ibuf=Icomp=40
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Ipipe=32
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Isf=40
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Idriv=36
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Vfp=142
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Vfs=192
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Vcomp=142
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Vdcl=186
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Vd=90
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Voffset=91
The measurements are done like this:
-
For noise measurements 1000 "events" are read out
-
For the analog data , dummy_out and analog_out
are measured with a dual channel oscilloscope. The analog values are determined
by averaging 100 samples (2Gs/s) in the "plateau" area of the analog signal.
-
The test pulse is given to 3 external capacitors, for a number
of values.
-
For the dynamic range measurements 6 external capacitors
are used which connect to 6 channels. This allows us to scan through the
-20 to +20MIP input range. The input voltage is generated by a LeCroy pulse
generator.
RESULTS :
Black => before irradiation
Green => after 100krad
Purple => after 200krad
Pulse width
Pulse width
of 3 channels
Gain(input
capacitance)
Gain of
3 channels
Peaktime(input
capacitance)
Pulse
shape scan
Rise time
