Abstracts Brochure - CERN

MOPCH177
MOPCH178
MOPCH179
MOPCH180
26-Jun-06 16:00 - 18:00 MOPCH — Poster Session
Status of HOM Load for the Cornell ERL Injector
V.D. Shemelin (Cornell University) P. Barnes, M. Liepe, V. Medjidzade,
H. Padamsee, G.R. Roy, J. Sears (Cornell University, Laboratory
for Elementary-Particle Physics)
100
The HOM load for the injector of the Energy
Recovery Linac at Cornell University is proposed
to work at temperature 80 K. The anticipated
absorbed power of the load is up
to 200 W. Versions with inner diameter of 78
and 106 mm are under development. Two different kinds of ferrites and a lossy ceramic are chosen as RF absorbers
for the load. Measurements of electromagnetic properties of absorbing materials have been performed in a frequency
range from 1 to 40 GHz. The engineering design of the load is ready and technological issues of brazing the absorbing
tiles and cooling have been solved. Brazing quality is controlled by IR thermograms. First warm measurements of a
prototype load are expected this summer.
Tests on MgB2 for Application to SRF Cavities
T. Tajima (LANL) I.E. Campisi (ORNL) A. Canabal-Rey (NMSU) Y.
Iwashita (Kyoto ICR) B. Moeckly (STI) C.D. Nantista, S.G. Tantawi
(SLAC) H.L. Phillips (Jefferson Lab)
Magnesium diboride (MgB2) has a transition
temperature (Tc) of ∼40 K, i.e., about four
times higher than niobium (Nb). The studies
in the last three years have shown that
it could have about one order of magnitude
less RF surface resistance (Rs) than Nb and seems much less power dependent compared to high-Tc materials such
as YBCO. In this paper we will present results on the dependence of Rs on surface magnetic fields and possibly the
critical RF surface magnetic field.
Design of a New Electropolishing System in the US for SRF Cavities
Electropolishing (EP) is considered the base-
T. Tajima (LANL) C. Boffo (Fermilab) M.P. Kelly (ANL)
line surface treatment for Superconducting
RF (SRF) cavities to achieve >35 MV/m accelerating
gradient for the International Linear Collider (ILC). Based on the lessons learned at the forerunners such
as KEK/Nomura, DESY and JLAB and on the recent studies, we have started a new design of the next EP system that
will be installed in the US. This paper presents requirements, specifications, and the detail of the system design as
well as the path forward towards the future industrialization.
Materials Testing with a High-Q RF Cavity
C.D. Nantista, V.A. Dolgashev, S.G. Tantawi (SLAC) I.E. Campisi
(ORNL) P. Kneisel (Jefferson Lab) T. Tajima (LANL)
Superconducting rf is of increasing importance
in particle accelerators. We have developed
a resonant cavity with high quality
factor and an interchangeable wall for testing
of superconducting materials*. A compact T·10 01 mode launcher attached to the coupling iris selectively excites the
azimuthally symmetric cavity mode, which allows a gap at the detachable wall and is free of surface electric fields
that could cause field emission, multipactor, and rf breakdown. The shape of the cavity is tailored to focus magnetic
field on the test wall, formed by a material sample affixed to a flange. We describe cryogenic experiments conducted