Options for the second Bunch Compressor Chicane of the CLIC Main Beam Line

For the second bunch compressor chicane at CLIC a maximum emittance growth of only 5% in the horizontal plane is allowed. The emittance growth is the conse- quence of incoherent and coherent synchrotron radiation emitted by the electrons along the chicane. Both effects are reviewed and various chicanes are compared in computer simulations. A chicane layout is found which preserves the emittance well within the specifications

CLIC Main beam dynamics in the ring to main LINAC transport

Prior to acceleration in the main linac, the particle beams created in the centrally located injector have to be transported to the outer ends of the CLIC site. This transport should not only preserve the beam quality but also shape, characterize and tune the phase space distribution to match the requirements at the entrance of the main linac. Hence, the performance of the transport downstream of the damping rings up to the main linac, the so called RTML, is crucial for the overall performance of CLIC. We discuss the different parts of the RTML and the occurring beam dynamics challenges. Their status is outlined and results of beam dynamics simulations are presented

BCR::ABL1 levels at first month after TKI discontinuation predict subsequent maintenance of treatment-free remission: A study from the “GRUPPO TRIVENETO LMC”

We analyzed BCR::ABL1 expression at stop and in the first month after discontinuation in 168 chronic myeloid leukemia patients who stopped imatinib or 2nd generation tyrosine kinase inhibitors (2G-TKIs) while in sustained deep molecular response. Patients were divided among those who maintained response (group 1, n = 123) and those who lost major molecular response (group 2, n = 45). Mean BCR::ABL1 RNA levels 1 month after discontinuation were higher in group 2 than in group 1 (p = 0.0005) and the difference was more evident 2 months after stop (p < 0.0001). The same trend was found both for imatinib and 2G-TKIs. A receiver operating characteristic (ROC) analysis to determine a threshold value of BCR::ABL1 at 1 month after discontinuation identified a cut-off value of 0.0051%, with 92.2% specificity, 31.7% sensitivity and a likelihood ratio of 4.087

Isolated terawatt attosecond hard X-ray pulse generated from single current spike

Isolated terawatt (TW) attosecond (as) hard X-ray pulse is greatly desired for four-dimensional investigations of natural phenomena with picometer spatial and attosecond temporal resolutions. Since the demand for such sources is continuously increasing, the possibility of generating such pulse by a single current spike without the use of optical or electron delay units in an undulator line is addressed. The conditions of a current spike (width and height) and a modulation laser pulse (wavelength and power) is also discussed. We demonstrate that an isolated TW-level as a hard X-ray can be produced by a properly chosen single current spike in an electron bunch with simulation results. By using realistic specifications of an electron bunch of the Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL), we show that an isolated, &gt;1.0 TW and similar to 36 as X-ray pulse at 12.4 keV can be generated in an optimized-tapered undulator line. This result opens a new vista for current XFEL operation: the attosecond XFEL

Simulation of Orbit Correction and Synchrotron Radiation Aspects in the Upgraded HERA Interaction Regions

In the upgraded HERA interaction regions, about 30kW of synchrotron radiation have to be passed safely through the high energy physics detectors. At a distance of about 11m from the interaction point a fraction of this synchrotron radiation is absorbed, while the remaining part is passed further on through the separated beam pipes. To protect the vacuum chamber between the IP and the 11m absorber against accidential mis-steering of the synchrotron radiation fan, four emergency absorbers are installed. On the other hand the HERA detectors are very sensitive to backgrounds from backscattered synchrotron radiation photons. The aperture of absorbers and other elements in the downstrem beamline have to be chosen such as to guarantee acceptable background conditions even with moderately missteered electron beams. To investigate the feasibility of this scheme, extensive simulations have been carried out taking into account realistic machine errors, such as magnet misalignments, monitor errors, optics distortions, etc. It is shown that under realistic conditions the synchrotron radiationfan can be safely controlled

Turn around loop and chicane for bunch compression and path length tuning in the CLIC drive beam

To achieve the proposed luminosity, phase and energy of the CLIC drive beam must meet tight specifications. The phase stability is achieved by a feedforward system consisting of two phase measurement stations intersected by a bunch compressor chicane in front of a turn around loop and a final chicane for bunch compression and path length correction behind the loop. This chicane is foreseen to compress the bunches to a final length of 0.4mm and should allow a path length tuning of 0.1mm. Suitable layouts for the turn around loop and the chicanes and results of beam dynamics simulations including incoherent and coherent synchrotron radiation are presented