The linear front-end is the analog processor chosen for the final integration into the pixel readout chip for the high-luminosity upgrade of the CMS experiment at the large hadron collider. The ...front-end has been included in the RD53A chip, designed by the CERN RD53 collaboration and submitted in 2017. An optimized version of the front-end has been designed, submitted, and tested in the framework of the RD53B developments. The optimization is mainly concerned with the time-walk performance of the front-end and with its threshold tuning capabilities. The article describes in detail such design improvements together with the results from the characterization of a small prototype chip including a 16 <inline-formula> <tex-math notation="LaTeX">\times </tex-math></inline-formula> 16 pixel matrix featuring both the RD53A and RD53B versions of the front-end. Test results show a significant reduction, about 10 ns for input signals close to the threshold, of the time-walk in the RD53B front-end, featuring a threshold dispersion smaller than 65 electrons r.m.s. after exposure to a total ionizing dose of 1 Grad of X-rays.
The Gigatracker (GTK) is a hybrid silicon pixel detector designed for the NA62 experiment at CERN. The beam spectrometer, made of three GTK stations, has to sustain high and non-uniform particle rate ...(∼1GHz in total) and measure momentum and angles of each beam track with a combined time resolution of 150ps. In order to reduce multiple scattering and hadronic interactions of beam particles, the material budget of a single GTK station has been fixed to 0.5% X0. The expected fluence for 100 days of running is 2×1014 1MeVneq/cm2, comparable to the one foreseen in the inner trackers of LHC detectors during 10 years of operation. To comply with these requirements, an efficient and very low-mass (<0.15%X0) cooling system is being constructed, using a novel microchannel cooling silicon plate. Two complementary read-out architectures have been produced as small-scale prototypes: one is based on a Time-over-Threshold circuit followed by a TDC shared by a group of pixels, while the other makes use of a constant-fraction discriminator followed by an on-pixel TDC. The read-out ASICs are produced in 130nm IBM CMOS technology and will be thinned down to 100μm or less. An overview of the Gigatracker detector system will be presented. Experimental results from laboratory and beam tests of prototype bump-bonded assemblies will be described as well. These results show a time resolution of about 170ps for single hits from minimum ionizing particles, using 200μm thick silicon sensors.
A 130 nm ASIC prototype for the NA62 Gigatracker readout Dellacasa, G.; Garbolino, S.; Marchetto, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2011, Letnik:
650, Številka:
1
Journal Article
Recenzirano
One of the most challenging detectors of the NA62 experiment is the silicon tracker, called Gigatracker. It consists of three hybrid silicon pixel stations, each one covering an area of 27
mm×60
mm. ...While the maximum pixel size is fairly large,
300
μ
m
×
300
μ
m
the system has to sustain a very high particle rate, 1.5
MHz/mm
2, which corresponds to 800
MHz for each station. To obtain an efficient tracking with such a high rate the required track timing resolution is 150
ps (rms). Therefore the front-end ASIC should provide for each pixel a 200
ps time measurement capability, thus leading to the requirement of time walk compensation and very compact TDCs. Moreover, Single Event Upset protection has to be implemented in order to protect the digital circuitry. An ASIC prototype has been realized in CMOS 130
nm technology, containing three pixel columns. The chip performs the time walk compensation by a Constant Fraction Discriminator circuit, while the time measurement is performed by a Time to Amplitude Converter based TDC, both of them implemented on each pixel cell. The End of Column circuit containing only digital logic is responsible for the data readout from the pixel cell. The whole chip works with a system clock of 160
MHz and the digital logic is SEU protected by the use of Hamming codes. The detailed architecture of the ASIC prototype and test results are presented.
The Gigatracker is a hybrid silicon pixel detector developed to track the highly intense NA62 hadron beam with a time resolution of 150
ps (rms). The beam spectrometer of the experiment is composed ...of three Gigatracker stations installed in vacuum in order to precisely measure momentum, time and direction of every traversing particle. Precise tracking demands a very low mass of the detector assembly (
<
0.5
%
X
0 per station) in order to limit multiple scattering and beam hadronic interactions. The high rate and especially the high timing precision requirements are very demanding: two R&D options are ongoing and the corresponding prototype read-out chips have been recently designed and produced in
0.13
μ
m
CMOS technology. One solution makes use of a constant fraction discriminator and on-pixel analogue-based time-to-digital-converter (TDC); the other comprises a delay-locked loop based TDC placed at the end of each pixel column and a time-over-threshold discriminator with time-walk correction technique. The current status of the R&D program is overviewed and results from the prototype read-out chips test are presented.
The NA62 Gigatracker pixel detector system Mazza, G.; Ceccucci, A.; Cortina, E. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2010, Letnik:
617, Številka:
1
Journal Article
Recenzirano
The silicon tracker for the NA62 experiment has to provide both a time resolution of 150
ps
rms and a space resolution of about
100
μ
m
rms
. These challenging specifications require the development ...of a new readout electronics in order to address the problem of measuring the tracks arrival time with such a high channel density. Moreover, the high particle density (up to
1.5
MHz
/
mm
2
in the center and 0.8–1
GHz in total) requires a high speed measurement and data transmission in order to keep the dead time below 1%.
We search for an axion-like particle (ALP) a through the process ψ(3686)→π+π−J/ψ, J/ψ→γa, a→γγ in a data sample of (2.71±0.01)×109ψ(3686) events collected by the BESIII detector. No significant ALP ...signal is observed over the expected background, and the upper limits on the branching fraction of the decay J/ψ→γa and the ALP-photon coupling constant gaγγ are set at 95% confidence level in the mass range of 0.165≤ma≤2.84GeV/c2. The limits on B(J/ψ→γa) range from 8.3×10−8 to 1.8×10−6 over the search region, and the constraints on the ALP-photon coupling are the most stringent to date for 0.165≤ma≤1.468GeV/c2.
PDF
