Abstract
The spatial and temporal performance of a four-plane system
composed of silicon sensors bump-bonded to Timepix4 ASICs is
assessed with a 180 GeV/c mixed hadron beam at the CERN SPS and
...reported in detail. Particle tracks are reconstructed using
time-space measurements from the four detector planes, two
100 μm planes perpendicular to the beam and two 300 μm
sensors under an angle of 9°. The spatial hit resolution
is assessed to be (15.5 ± 0.5) μm and (4.5 ± 0.3) μm
for 100 μm and 300 μm thick sensors, respectively.
The timestamps from the detectors are also measured with fine
precision, yielding time resolutions of (452 ± 10) ps,
(420 ± 10) ps, (639 ± 10) ps, (631 ± 10) ps for the two
100 μm and two 300 μm thick sensors respectively.
These measurements are combined to a track time resolution of
(340 ± 5) ps. The design of the detector system is described
together with its data acquisition system, operational
infrastructure, and dedicated software.
This article describes a custom VHDL firmware implementation of a two-dimensional cluster-finder architecture for reconstructing hit positions in the new vertex pixel detector (VELO) that is part of ...the LHCb Upgrade. This firmware has been deployed to the existing FPGA cards that perform the readout of the VELO, as a further enhancement of the DAQ system, and will run in real time during physics data taking, reconstructing VELO hits coordinates on-the-fly at the LHC collision rate. This pre-processing allows the first level of the software trigger to accept an 11% higher rate of events, as the ready-made hit coordinates accelerate the track reconstruction and consumes significantly less electrical power. It additionally allows the raw pixel data to be dropped at the readout level, thus saving approximately 14% of the DAQ bandwidth. Detailed simulation studies have shown that the use of this real-time cluster finding does not introduce any appreciable degradation in the tracking performance in comparison to a full-fledged software implementation. This work is part of a wider effort aimed at boosting the real-time processing capability of HEP experiments by delegating intensive tasks to dedicated computing accelerators deployed at the earliest stages of the data acquisition chain.
This article describes a custom VHDL firmware implementation of a two-dimensional cluster-finder architecture for reconstructing hit positions in the new vertex pixel detector (VELO) that is part of ...the LHCb Upgrade. This firmware has been deployed to the existing FPGA cards that perform the readout of the VELO, as a further enhancement of the DAQ system, and will run in real time during physics data taking, reconstructing VELO hits coordinates on-the-fly at the LHC collision rate. This pre-processing allows the first level of the software trigger to accept a 11% higher rate of events, as the ready-made hits coordinates accelerate the track reconstruction and consumes significantly less electrical power. It additionally allows the raw pixel data to be dropped at the readout level, thus saving approximately 14% of the DAQ bandwidth. Detailed simulation studies have shown that the use of this real-time cluster finding does not introduce any appreciable degradation in the tracking performance in comparison to a full-fledged software implementation. This work is part of a wider effort aimed at boosting the real-time processing capability of HEP experiments by delegating intensive tasks to dedicated computing accelerators deployed at the earliest stages of the data acquisition chain.
The LHCb detector has undergone a major upgrade for LHC Run 3. This Upgrade I detector facilitates operation at higher luminosity and utilises full-detector information at the LHC collision rate, ...critically including the use of vertex information. A new vertex locator system, the VELO Upgrade, has been constructed. The core element of the new VELO are the double-sided pixelated hybrid silicon detector modules which operate in vacuum close to the LHC beam in a high radiation environment. The construction and quality assurance tests of these modules are described in this paper. The modules incorporate 200 \mum thick, n-on-p silicon sensors bump-bonded to 130 \nm technology ASICs. These are attached with high precision to a silicon microchannel substrate that uses evaporative CO\(_2\) cooling. The ASICs are controlled and read out with flexible printed circuits that are glued to the substrate and wire-bonded to the chips. The mechanical support of the module is given by a carbon fibre plate, two carbon fibre rods and an aluminium plate. The sensor attachment was achieved with an average precision of 21 \(\mathrm{\mu m}\), more than 99.5\% of all pixels are fully functional, and a thermal figure of merit of 3 \mathrm{Kcm^{2}W^{-1}}$ was achieved. The production of the modules was successfully completed in 2021, with the final assembly and installation completed in time for data taking in 2022.
A
bstract
We review the experimental methods to measure mixing and time-dependent
CP
violation in
D
0
decays into two hadrons. While these phenomena are usually neglected for
D
0
→
K
−
π
+
decays, ...this approximation is not always justified. In particular, it produces a bias on the measurement of the parameter
y
CP
, when this is performed by relying on
D
0
→
K
−
π
+
decays as a normalisation channel, whose size is around 40% of the precision of the current world average. Finally, we estimate the sensitivity to the weak mixing phases achievable by studying
D
0
→
K
−
π
+
and untagged
D
→
K
−
π
+
decays, where
D
stands for either of the
D
0
and
D
¯
0
mesons. Contrary to Cabibbo-suppressed
D
0
→
h
+
h
−
decays, these decay channels allow to measure these phases without final-state dependent nuisance contributions from the decay amplitudes, but their sensitivity is lower by a factor of six.
Objective:
To determine the effectiveness of Kinesio taping compared to compression garments during maintenance phase of complex decongestive therapy for breast cancer–related lymphedema.
Design:
...Randomized, cross-over, controlled trial.
Setting:
Outpatient tertiary-level hospital rehabilitation setting.
Subjects:
Randomized sample of 30 women with breast cancer–related lymphedema.
Interventions:
Participants received two interventions, Kinesio taping and compression garment, both lasting four weeks, whose order was randomized by blocks. A four-week washout period was established prior to the interventions and between them.
Measurements:
The main outcome was the lymphedema Relative Volume Change. Secondary outcomes were range of motion of arm joints, self-perception of comfort, and lymphedema-related symptoms (pain, tightness, heaviness, and hardness).
Results:
The decrease in the Relative Volume Change was greater in the Kinesio taping intervention (–5.7%, SD = 2.0) compared to that observed using compression garments (–3.4%, SD = 2.9) (P < 0.001). The range of motion of five upper-limb movements increased after applying taping (between 5.8° and 16.7°) (P < 0.05), but not after compression (P > 0.05). In addition, taping was perceived as more comfortable by patients (between 2.4 and 3 points better than compression in four questions with a 5-point scale (P < 0.001)) and further reduced lymphedema-related symptoms compared to compression (between 0.96 and 1.40 points better in four questions with a 6-point scale (P < 0.05)).
Conclusion:
Kinesio taping was more effective than compression garments for reducing the lymphedema volume, with less severe lymphedema-related symptoms, better improvement of upper-limb mobility, and more comfort.
Full text
Available for:
NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
Objective
The objective of this study is to compare the effectiveness of complex physical therapy combined with intermittent pneumatic compression (CPT + IPC) versus Kinesio taping (KT) for breast ...cancer‐related lymphedema.
Methods
A cross‐over clinical trial was conducted in 43 women with lymphedema. All participants received two interventions: CPT + IPC and KT, both lasting 3 weeks and a washout period. The main outcome variable was the relative volume change (RVC). The secondary variables were Satisfaction Questionnaire about Textile Therapeutic Devices used for Breast Cancer‐Related Lymphedema, Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, motion range of upper limb and lymphedema‐related symptoms.
Results
The RVC reduction was greater with CPT + IPC (−2.2%, SD = 4.7) versus KT (−0.9%, SD = 1.7) (P = 0.002). KT was more satisfactory than multilayer bandaging (8.9 points difference, P < 0.001) and improved DASH score more than CPT + IPC (14.3 points difference, P = 0.002). Regarding motion ranges, only shoulder movements showed significant improvement with CPT + IPC compared with KT (differences between 5.6° and 11.4°). Of the symptoms assessed, only pain reduction showed a significant improvement with KT versus CPT + IPC (0.5 points, P = 0.035).
Conclusions
CPT + IPC achieved higher RVC and greater improvement in th shoulder motion range than KT. Conversely, KT was more satisfactory than multilayer bandaging, obtained better DASH scores and relieved pain more than CPT + IPC.
Clinical Registration
ClinicalTrial registration number: NCT03051750 (date of registration 14 February 2017).
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Starting from the next LHC run, the upgraded LHCb High Level Trigger will process events at the full LHC collision rate (averaging 30 MHz). This challenging goal, tackled using a large and ...heterogeneous computing farm, can be eased addressing lowest-level, more repetitive tasks at the earliest stages of the data acquisition chain. FPGA devices are very well-suited to perform with a high degree of parallelism and efficiency certain computations, that would be significantly demanding if performed on general-purpose architectures. A particularly time-demanding task is the cluster-finding process, due to the 2D pixel geometry of the new LHCb pixel detector. We describe here a custom highly parallel FPGA-based clustering algorithm and its firmware implementation. The algorithm implementation has shown excellent reconstruction quality during qualification tests, while requiring a modest amount of hardware resources. Therefore it can run in the LHCb FPGA readout cards in real time, during data taking at 30 MHz, representing a promising alternative solution to more common CPU-based algorithms.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Modern Physics Letters A, 37, No. 24, 2230012 (2022) After playing a pivotal role in the birth of the Standard Model in the 70's,
the study of charm physics has undergone a revival during the last ...decade,
triggered by a wealth of precision measurements from the charm and $B$
factories, and from the CDF and especially the LHCb experiments. In this
article, we sum up how the unique phenomenology of charmed hadrons can be used
to test the Standard Model and we review the latest measurements performed in
this field by the LHCb experiment. These include the historic first
observations of $CP$ violation and of a nonzero mass difference between the
charmed neutral-meson mass eigenstates, the most precise determination of their
decay-width difference to date, and a search for time-dependent $CP$ violation
reaching the unprecedented precision of $10^{-4}$. These results challenge our
comprehension of nonperturbative strong interactions, and their interpretation
calls for further studies on both the theoretical and experimental sides. The
upcoming upgrades of the LHCb experiment will play a leading role in this
quest.
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