Conveners
HOM Measurements, Beam Effects, and Diagnostics
- Nicoleta Baboi (DESY)
HOM Measurements, Beam Effects, and Diagnostics
- Olivier Napoly (FNAL)
Dr
Alex Lumpkin
(Fermilab)
10/1/18, 1:00 PM
Oral presentation
We report the direct observations of sub-macropulse beam centroid oscillations correlated with higher order modes (HOMs) which were generated by off-axis electron beam steering in TESLA-type SCRF cavities. The experiments were performed at the Fermilab Accelerator Science and Technology (FAST) facility using its unique configuration of a photocathode rf gun injecting beam into two separated...
Dr
Adam Bartnik
(Cornell University)
10/1/18, 1:30 PM
Oral presentation
A search for HOMs in Cornell’s ERL main linac cavity installed in a Horizontal Test Cryomodule (HTC) has been carried out using a bunch charge modulation method, as part of the effort towards building an Energy Recovery Linac (ERL). The beam-based HOM measurements offer the significant advantage of being able to detect trapped modes invisible to both the RF pickup probes and HOM damping loads,...
Dr
Olivier Napoly
(FNAL)
10/1/18, 2:00 PM
Oral presentation
Superconducting RF cavities are high quality symmetric resonators that support many
different modes of oscillation, with high precision signals and unsurpassable dynamic range. Owing to their approximate axial symmetry, modes can be identified according to their monopole, dipole and quadrupole nature. Higher Order Modes (HOM) excited by bunched beams in SRF cavities hence coupled respectively...
Mr
Junhao Wei
(DESY)
10/1/18, 2:30 PM
Oral presentation
FLASH is a free-electron laser driven by a superconducting linac at DESY in Hamburg. It is able to generate high-brilliance XUV and soft X-ray pulses. Many accelerating cavities are equipped with HOMBPMs (Higher Order Mode based Beam Position Monitors) to align the beam and monitor the transverse beam position. We applied an efficient measurement and signal analysis with various data process...
William Lou
(Cornell University)
10/1/18, 3:30 PM
Oral presentation
The Cornell Brookhaven Energy-Recovery-Linac (ERL) Test Accelerator (CBETA) is currently under construction at the Cornell University's Wilson Laboratory. The primary structures in CBETA for beam recirculation include the Main Linac Cryomodule (MLC) and the FFAG beamline. As the electron bunches pass through the MLC cavities, Higher Order Modes (HOMs) are excited. The recirculating bunches...
Mr
Nilanjan Banerjee
(Cornell University)
10/1/18, 4:00 PM
Oral presentation
The Cornell-BNL ERL Test Accelerator (CBETA) is a new multi-turn high current energy recovery linac currently under construction at Cornell University with a stated goal of 40 mA CW through the injector and 320 mA through the main linac. Higher Order Modes (HOMs) excited by the high current beam will be damped using beamline absorbers and the resulting energy will be converted to heat. In this...
ANDREI Lunin
(FNAL)
10/1/18, 4:30 PM
Oral presentation
Production and testing of 1.3 GHz cryomodules for the LCLS-II project is ongoing at Fermilab. Each cryomodule is assembled of eight superconducting TESLA-shape elliptical cavities equipped with two High Order Mode (HOM) coupler ports. Measurement of the HOM spectrum is a part of the cavities incoming quality control inspection and the final cryomodule qualification cold test at the Cryomodule...
