In dark gray forest soil, the use of
15
N fertilizer nitrogen by spring wheat when seeds were inoculated with microbial biopreparations was assessed. The use of the method under study increased the ...weight of grain on the PK background by 25–42%. Increases from inoculation with preparations based on diazotrophs Ch-13 and V 167 strains were equivalent and amounted to 78–97 g/m
2
. In the variant with V 417, the increase reached 132 g/m
2
and was at the level of use of N45 (143 g/m
2
). In combination with N45, the biopreparation based on strain Ch-13 was characterized by maximum efficiency. When using biopreparations on the PK-background, the accumulation of N in the yield increased by 2.33–2.64 g/m
2
and by 1.33–1.70 g/m
2
on the NRK background. In the variants with biopreparations, the 20% of the yield was formed due to biological nitrogen, while its greatest accumulation (24.8%) occurred when using V 417. The maximum share of
15
N (23.7%) in the yield was noted when N90 was applied. When using biopreparations, plants accumulate approximately 8.5% of “extra”-N and its highest content (11.5–12.1%) was recorded when Naa was added. Mineral fertilizer nitrogen mainly accumulates in grain (95–96%) and only 4–5% accumulate in spring wheat straw. When applying N45 and N90, plants use 46 and 42% of fertilizer nitrogen, respectively, and the use of biopreparations increases the value of this indicator to 51–53%. Approximately 33–36% of the introduced dose of
15
N is fixed in the soil, and this indicator increased up to 30% when using biopreparations. Losses of
15
N reach 33–36%, while losses decrease to 17–19% with the introduction of biopreparations. The minimum accumulation of fertilizer nitrogen in plants (42%), the maximum fixation in the soil (36%), and losses (23%) were observed when N90 was applied.
—
The time and energy resolutions were measured for four prototypes of the PHOS electromagnetic calorimeter for the ALICE experiment at the Large Hadron Collider at CERN. Each prototype was made up ...of nine identical detection elements assembled as a 3 × 3 array. The detection element was based on a lead tungstate (PbWO
4
) scintillating crystal with a length of 180 mm and a cross section of 22 × 22 mm
2
, which was viewed from its end face by a photodetector. Avalanche photodiodes and silicon photomultipliers with different active areas (Hamamatsu, Japan) were used as photodetectors. The measurements were made with the electron component of secondary particle beams of the PS proton synchrotron at CERN in the momentum range of 1−10 GeV/
c
at a temperature of 17.5°C.
It is shown that an increase in the area of photodetectors allows the PHOS electromagnetic calorimeter of the ALICE experiment to operate at room temperature with better spectrometric ...characteristics. The linearity of the calorimeter response has been investigated in the 1–110 GeV energy range using both Hamamatsu S8664-1010 avalanche photodiodes with a large area (10 × 10 mm
2
) and arrays of MPPC Hamamatsu S12572-015C silicon photomultipliers with a sensitive area of 6 × 6 mm
2
. The calorimeter based on avalanche photodiodes is linear in the energy range under investigation compared to a calorimeter composed of silicon-photomultiplier arrays.
Experimental investigations have shown that a timing device based on a constant-fraction discriminator is capable of providing a time resolution of approximately 0.5 ns and a timing error of ...approximately ±0.25 ns in the energy range of 0.8−1.8 GeV. In the region of “low” energies (<0.6 GeV), the time resolution is decreased by the influence of detector noise, whose level is ~3–5 mV for most scintillation detectors under investigation.
The use of S12572 MPPC silicon photomultipliers (Hamamatsu) for improving the timing characteristics of the PHOS electromagnetic calorimeter in the ALICE experiment at CERN is described. It is shown ...that by introducing an additional photodetector, that is, a silicon photomultiplier, it is possible, without worsening the energy resolution, to significantly improve the time resolution of the PHOS spectrometer from the current values of 3–4 ns to 150–200 ps.
The PHENIX Electromagnetic Calorimeter (EMCal) is used to measure the spatial position and energy of electrons and photons produced in heavy ion collisions. It covers the full central spectrometer ...acceptance of 70°⩽
θ⩽110° with two walls, each subtending 90° in azimuth. One wall comprises four sectors of a Pb-scintillator sampling calorimeter and the other has two sectors of Pb-scintillator and two of a Pb-glass Cherenkov calorimeter. Both detectors have very good energy, spatial and timing resolution, while the Pb-scintillator excels in timing and the Pb-glass in energy measurements. Also, having two detectors with different systematics increases the confidence level of the physics results. Design and operational parameters of the Pb-scintillator, Pb-glass and special readout electronics for EMCal are presented and running experience during the first year of data taking with PHENIX is discussed. Some examples of data taken during the first run are shown.
For the first time, full size lead tungstate crystals of different suppliers, quality and dopant concentration have been irradiated with gamma-rays at low temperatures down to -25degC at IHEP ...Protvino. In contrast to the behavior at room temperature, increased damage and extremely slow recovery processes have been observed. These first results are discussed in the light of several very different interpretations. Further more sensitive measurements are under preparation. The outcome will have a strong impact on the presently assembled ALICE-PHOS detector and the design of the EM calorimeter of PANDA at the future FAIR facility.
The Time of Flight (TOF) resolution of one of the LHC ALICE detectors, a prototype of the electromagnetic calorimeter PHOS (PHOton Spectrometer), was measured in beam tests carried out at CERN PS. ...The prototype of the calorimeter consists of 256
(
22
×
22
×
180
mm
3
)
cells of light-detecting
PbWO
4
(PWO) monocrystals read out with
5
×
5
mm
2
Avalanche Photo Diodes (APDs). Three dedicated front end cards with 24 channels of electronics were designed and produced for using in the tests, each channel consisting of one fast and two slow shapers, a time to amplitude converter and three identical 12-bit peak sensitive Analog to Digital Converters (ADCs). The high voltage bias regulator for APD is located on the same card. The measured TOF resolution is described as
σ
t
=
0.24
/
E
GeV
2
+
0.4
ns
.
Lead tungstate crystals for the ALICE/CERN experiment Ippolitov, M.; Beloglovsky, S.; Burachas, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2005, Letnik:
537, Številka:
1-2
Journal Article
Recenzirano
Light yield, emission and decay time spectra, and optical transmission of ∼3600 (dimensions 22×22×180mm3) PbWO4 (PWO) crystals were measured with test benches. Radiation beam-test results of PWO ...crystals are presented.
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