200 research outputs found
Storage Ring Based EDM Search — Achievements and Goals
This paper summarizes the experimental achievements of the JEDI (Jülich Electric Dipole moment Investigations) Collaboration to exploit and demonstrate the feasibility of charged particle Electric Dipole Moment searches with storage rings at the Cooler Synchrotron COSY of the Forschungszentrum Jülich. Recent experimental results, design and optimization of critical accelerator elements, progress in beam and spin tracking, and future goals of the R & D program at COSY are presented
The application of massively parallel sequencing technologies in diagnostics
Massively parallel sequencing (MPS) is rapidly evolving and is starting to be utilized by the clinical field as well as diagnostics. We describe major recent advances that have come about as a result of the application of MPS in the biomedical field and the first approaches in medical genetics that have made use of MPS. Without any doubt, MPS has proven to be a very powerful technique. To unravel the capabilities of MPS for patient care, the most important aspect for the acceptance of MPS within clinics and diagnostics is to guarantee that the large amount of data undergoes vitally important analyses and interpretation and is securely managed
Electron self-injection threshold for the tandem-pulse laser wakefield accelerator
A controllable injection scheme is key to producing high quality laser-driven
electron beams and X-rays. Self-injection is the most straightforward scheme
leading to high current and peak energies, but is susceptible to variations in
laser parameters and target characteristics. In this work improved control of
electron self-injection in the nonlinear cavity regime using two laser-pulses
propagating in tandem is investigated. In particular the advantages of the
tandem-pulse scheme in terms of injection threshold, electron energy and beam
properties in a regime relevant to betatron radiation are demonstrated.
Moreover it is shown that the laser power threshold for electron self-injection
can be reduced by up to a factor of two compared to the standard, single-pulse
wakefield scheme.Comment: 11 pages, 9 figures, submitted for publication (2019
Polarized Proton Beams from Laser-induced Plasmas
We report on the concept of an innovative source to produce polarized
proton/deuteron beams of a kinetic energy up to several GeV from a laser-driven
plasma accelerator. Spin effects have been implemented into the PIC simulation
code VLPL to make theoretical predictions about the behavior of proton spins in
laser-induced plasmas. Simulations of spin-polarized targets show that the
polarization is conserved during the acceleration process. For the experimental
realization, a polarized HCl gas-jet target is under construction using the
fundamental wavelength of a Nd:YAG laser system to align the HCl bonds and
simultaneously circular polarized light of the fifth harmonic to
photo-dissociate, yielding nuclear polarized H atoms. Subsequently, their
degree of polarization is measured with a Lamb-shift polarimeter. The final
experiments, aiming at the first observation of a polarized particle beam from
laser-generated plasmas, will be carried out at the 10 PW laser system SULF at
SIOM/Shanghai.Comment: 7 pages, 7 figure
Scaling laws for the (de-)polarization time of relativistic particle beams in strong fields
The acceleration of polarized electrons and protons in strong laser and
plasma fields is a very attractive option to obtain polarized beams in the GeV
range. We investigate the feasibility of particle acceleration in strong fields
without destroying an initial polarization, taking into account all relevant
mechanisms that could cause polarization losses, i.e. the spin precession
described by the T-BMT equation, the Sokolov-Ternov effect and the
Stern-Gerlach force. Scaling laws for the (de-)polarization time caused by
these effects reveal that the dominant polarization limiting effect is the
rotation of the single particle spins around the local electromagnetic fields.
We compare our findings to test-particle simulations for high energetic
electrons moving in a homogeneous electric field. For high particle energies
the observed depolarization times are in good agreement with the analytically
estimated ones.Comment: 17 pages and 4 figure
Simulation of Polarized Beams from Laser-Plasma Accelerators
The generation of polarized particle beams still relies on conventional
particle accelerators, which are typically very large in scale and budget.
Concepts based on laser-driven wake-field acceleration have strongly been
promoted during the last decades. Despite many advances in the understanding of
fundamental physical phenomena, one largely unexplored issue is how the
particle spins are influenced by the huge magnetic fields of plasma and, thus,
how highly polarized beams can be produced. The realization of laser-plasma
based accelerators for polarized beams is now being pursued as a joint effort
of groups from Forschungszentrum J\"ulich (Germany), University of Crete
(Greece), and SIOM Shanghai (China) within the ATHENA consortium. As a first
step, we have theoretically investigated and identified the mechanisms that
influence the beam polarization in laser-plasma accelerators. We then carried
out a set of Particle-in-cell simulations on the acceleration of electrons and
proton beams from gaseous and foil targets. We could show that intense
polarized beams may be produced if pre-polarized gas targets of high density
are employed. In these proceedings we further present that the polarization of
protons in HT and HCl gas targets is largely conserved during laser wake-field
acceleration, even if the proton energies enter the multi-GeV regime. Such
polarized sources for electrons, protons, deuterons and He ions are now
being built in J\"ulich. Proof-of-principle measurements at the (multi-)PW
laser facilities PHELIX (GSI Darmstadt) and SULF (Shanghai) are in preparation.Comment: submitted to IO
Novel physics opportunities at the HESR-Collider with PANDA at FAIR
Exciting new scientific opportunities are presented for the PANDA detector at
the High Energy Storage Ring in the redefined
collider mode, HESR-C, at the Facility for Antiproton and Ion Research (FAIR)
in Europe. The high luminosity, cm s, and a wide
range of intermediate and high energies, up to 30 GeV
for collisions will allow to explore a wide range
of exciting topics in QCD, including the study of the production of excited
open charm and bottom states, nuclear bound states containing heavy
(anti)quarks, the interplay of hard and soft physics in the dilepton
production, and the exploration of the regime where gluons -- but not quarks --
experience strong interaction.Comment: 29 pages, 5 figures. To appear in the memorial volume for Walter
Greiner of the Springer-Nature FIAS Interdisciplinary Science serie
Phase locking the spin precession in a storage ring
This letter reports the successful use of feedback from a spin polarization
measurement to the revolution frequency of a 0.97 GeV/ bunched and polarized
deuteron beam in the Cooler Synchrotron (COSY) storage ring in order to control
both the precession rate ( kHz) and the phase of the horizontal
polarization component. Real time synchronization with a radio frequency (rf)
solenoid made possible the rotation of the polarization out of the horizontal
plane, yielding a demonstration of the feedback method to manipulate the
polarization. In particular, the rotation rate shows a sinusoidal function of
the horizontal polarization phase (relative to the rf solenoid), which was
controlled to within a one standard deviation range of rad. The
minimum possible adjustment was 3.7 mHz out of a revolution frequency of 753
kHz, which changes the precession rate by 26 mrad/s. Such a capability meets a
requirement for the use of storage rings to look for an intrinsic electric
dipole moment of charged particles
A combined computational and functional approach identifies IGF2BP2 as a driver of chemoresistance in a wide array of pre-clinical models of colorectal cancer
Aim Chemoresistance is a major cause of treatment failure in colorectal cancer (CRC) therapy. In this study, the
impact of the IGF2BP family of RNA-binding proteins on CRC chemoresistance was investigated using in silico, in vitro,
and in vivo approaches.
Methods Gene expression data from a well-characterized cohort and publicly available cross-linking immunoprecipi‑
tation sequencing (CLIP-Seq) data were collected. Resistance to chemotherapeutics was assessed in patient-derived
xenografts (PDXs) and patient-derived organoids (PDOs). Functional studies were performed in 2D and 3D cell culture
models, including proliferation, spheroid growth, and mitochondrial respiration analyses.
Results We identifed IGF2BP2 as the most abundant IGF2BP in primary and metastastatic CRC, correlating with
tumor stage in patient samples and tumor growth in PDXs. IGF2BP2 expression in primary tumor tissue was signif‑
cantly associated with resistance to selumetinib, geftinib, and regorafenib in PDOs and to 5-fuorouracil and oxalipl‑
atin in PDX in vivo. IGF2BP2 knockout (KO) HCT116 cells were more susceptible to regorafenib in 2D and to oxaliplatin,
selumitinib, and nintedanib in 3D cell culture. Further, a bioinformatic analysis using CLIP data suggested stabiliza‑
tion of target transcripts in primary and metastatic tumors. Measurement of oxygen consumption rate (OCR) and
extracellular acidifcation rate (ECAR) revealed a decreased basal OCR and an increase in glycolytic ATP production
rate in IGF2BP2 KO. In addition, real-time reverse transcriptase polymerase chain reaction (qPCR) analysis confrmed
decreased expression of genes of the respiratory chain complex I, complex IV, and the outer mitochondrial membrane
in IGF2BP2 KO cells. Conclusions IGF2BP2 correlates with CRC tumor growth in vivo and promotes chemoresistance by altering mito‑
chondrial respiratory chain metabolism. As a druggable target, IGF2BP2 could be used in future CRC therapy to
overcome CRC chemoresistance
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