2,101 research outputs found
Crystal structure of tert-butyl 2-phenylethylcarbamate, C13H19NO2
Abstract
C13H19NO2, monoclinic, P21/n (no. 14), a = 5.2692(3) Å, b = 13.8663(9) Å, c = 17.8020(13) Å, β = 93.323(6)°, V = 1298.50(15), Z = 4, R
gt(F) = 0.0590, wR
ref(F
2) = 0.1932, T = 293 K.</jats:p
Methyl N-(2-bromo-4-chlorophenyl)carbamate
In the title molecule, C8H7BrClNO2, the bromochlorophenyl ring is inclined to
the methylcarbamate unit by 32.73 (7). In the crystal, N—HO hydrogen
bonds form chains of molecules parallel to [100]
Crystal structure of 1,1-dimethyl-3-(2-phenylethyl)urea, C11H16N2O
Abstract
C11H16N2O, orthorhombic, Pbca (no. 61), a = 10.7388(6) Å, b = 9.8449(5) Å, c = 21.1259(14) Å, V = 2233.5(2) Å3, Z = 8, R
gt
(F) = 0.0582, wR
ref
(F
2) = 0.1795, T = 293 K.</jats:p
Charge collection properties of irradiated depleted CMOS pixel test structures
Edge-TCT and charge collection measurements with passive test structures made
in LFoundry 150 nm CMOS process on p-type substrate with initial resistivity of
over 3 kcm are presented. Measurements were made before and after
irradiation with reactor neutrons up to 210
n/cm. Two sets of devices were investigated: unthinned (700
m) with substrate biased through the implant on top and thinned (200
m) with processed and metallised back plane.
Depleted depth was estimated with Edge-TCT and collected charge was measured
with Sr source using an external amplifier with 25 ns shaping time.
Depleted depth at given bias voltage decreased with increasing neutron fluence
but it was still larger than 70 m at 250 V after the highest fluence.
After irradiation much higher collected charge was measured with thinned
detectors with processed back plane although the same depleted depth was
observed with Edge-TCT. Most probable value of collected charge of over 5000
electrons was measured also after irradiation to 210
n/cm. This is sufficient to ensure successful operation of
these detectors at the outer layer of the pixel detector in the ATLAS
experiment at the upgraded HL-LHC
Gain Recovery in Heavily Irradiated Low Gain Avalanche Detectors by High Temperature Annealing
Studies of annealing at temperatures up to 450C with LGADs irradiated
with neutrons are described. It was found that the performance of LGADs
irradiated with 1.5e15 n/cm was already improved at 5 minutes of annealing
at 250C. Isochronal annealing for 30 minutes in 50C steps
between 300C and 450C showed that the largest beneficial effect
of annealing is at around 350C. Another set of devices was annealed for
60 minutes at 350C and this annealing significantly increased
V. The effect is equivalent to reducing the effective acceptor
removal constant by a factor of 4. Increase of V is the
consequence of increased effective space charge in the gain layer caused by
formation of electrically active defects or re-activation of interstitial Boron
atoms
Timing performance of small cell 3D silicon detectors
A silicon 3D detector with a single cell of 50x50 um2 was produced and
evaluated for timing applications. The measurements of time resolution were
performed for 90Sr electrons with dedicated electronics used also for
determining time resolution of Low Gain Avalanche Detectors (LGADs). The
measurements were compared to those with LGADs and also simulations. The
studies showed that the dominant contribution to the timing resolution comes
from the time walk originating from different induced current shapes for hits
over the cell area. This contribution decreases with higher bias voltages,
lower temperatures and smaller cell sizes. It is around 30 ps for a 3D detector
of 50x50 um2 cell at 150 V and -20C, which is comparable to the time walk due
to Landau fluctuations in LGADs. It even improves for inclined tracks and
larger pads composed of multiple cells. A good agreement between measurements
and simulations was obtained, thus validating the simulation results
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