Getting in touch:
- Address:
- Volker Ziemann
- Uppsala University
- Department of Physics and Astromomy
- Angström Laboratory, room 82108
- Lagerhyddsvägen 1
- Box 516
- 75120 Uppsala, Sweden
- Telephone:
- +46 (18) 471-3867
- Faximile:
- +46 (18) 471-5999
- Email:
- volker.ziemann@physics.uu.se
What I am/was working on:
- XFEL Laser-heater
- We will build the laser heater as a Swedish in-kind contribution to the construction of
the XFEL with a grant from the Swedish research council
VR.
- Center for Accelerator and Instrumentation Development (CAI)
- In February 2007 the faculty of science appointed me director of the
Center for Accelerator and Instrumentation Development.
- CERN Accelerator School on Digital Signal Processing
- I chaired the local organizing committee for the
CERN Accelerator School in Sigtuna
that took place from May 31 until June 9, 2007.
- Course on Accelerator Physics and Technology
- for 4th year and graduate students.
- Two-beam test-stand for CTF3 at CERN in Geneva
- The Swedish science council (VR) and the Knut and Alice Wallenberg Foundation support us
in the design and construction of the
Two-beam Test-stand
at the CLIC-Test Facility (CTF3) where the
novel CLIC acceleration method with the deceleration (PETS) and acceleration
structures will be tested with parameters close to those envisioned for CLIC.
- Optical Replica Synthesizer for the FLASH FEL facility at DESY in Hamburg
- Within the newly founded (March 2006) SU-KTH-UU Free-Electron-Laser center and
in collaboration with Mats Larssons group in Stockholm and DESY we will build a
diagnostic setup to measure the length of
femto-second electron bunches by generating a infrared light-pulse that has the
envelope of the electron bunch and diagnosing this by 'Frequency resolved optical
gating' (FROG) methods.
- Post-collision beam line for CLIC
- I am collaborating on the design of the
beam line between the interaction point and the beam dump for the 1.5+1.5 TeV linear collider CLIC within
the ILPS workpackage of the 6th European framework program EuroTeV.
- Confocal Resonator Pickup Design
- We did an analytical design
study of a pick-up configuration that allows to monitor the bunch
spacing and/or the bunch length in the CTF3 drive beam. This project
is part of the Diagnostic work package of the 6th European framework
program EuroTeV.
- Beam-Target interaction with the Pellet Target
- In a pellet target the pellets are rather thick, but a particle of the
beam hits it only rarely. This can be contrasted to a more continuous
target where the beam particles hit target particles much more frequently.
This is done as part of an INTAS collaboration (2004-2006) and continues
as part of the 6th European framework program DIRACsecondary beams.
- The Svedberg Laboratory in Uppsala, Sweden, 1995-2005
- I worked as an accelerator physicist at a Swedish national lab, the
The Svedberg Laboratory,
located at Uppsala University.
We are mostly doing research in nuclear physics,
but also in material sciences and biomedical sciences, where we are
involved in clinical treatment of patients with proton therapy. The
research is done using the Gustaf-Werner cyclotron, which can produce
up to 180 MeV protons, but also a large variety of other ions.
The beam is delivered to a number of experimental areas through a
complex of
beam lines with a total length of about 150 m. At the end of
one beamline is
CELSIUS, an ion storage ring with 82 m circumference,
used to store protons and other elements with masses up to Argon. We
employ an electron-cooler in order to improve the beam quality, but
also to accumulate more ions during injection. The maximum energy
we can reach with protons is currently 1.3 GeV. After CELSIUS was closed
down in 2005 I moved the the neighboring department for Nuclear and Particle physics.
- Diagnosing non-linear aberrations with the wobbling method
- During my time at CERN I devised a method to measure coefficients in
the Hamiltonian by oscillating the beam with small dipole magnets and
observe the mixing frequencies generated by the non-linear magnets. This
method was applied in CERN-SL-2002-018 (AP)
to see whether it is possible to measure the dodecapole component of the
LHC triplet magnets.
- Fast spectrum analyzer
- We use a AD-6640 Receiver Signal Processor Evaluation board plus some
software on a Linux-PC to build a very fast spectrum analyzer that we
use to observe Schottky signals in CELSIUS, among other things to
measure cooling forces and the target thickness.
- Digital Feedback System to Control Self-Bunching in
CELSIUS:
- I worked out the design parameters for a feedback system thats
uses a fast ADC to digitize the BPM sum signal, pipes that through
a FIR filter implemented in programmable logic on through a DAC,
amplifier, and longitudinal kicker back to the beam. The FIR
filter coefficients can be used to simulate artificial and real
wake potentials. If they are identical, but opposite in sign
to the real wake potential of the ring they can be used to
reduce self-bunching. The work is documented in an
internal note and the manuscript is published in
Phys. Rev. ST Accel. Beams
4, 042801 (2001).
- Fast Beam Position System for CELSIUS:
- We can now measure turn-by-turn beam
positions in CELSIUS using our SHARC data acquisistion
system. Contributed to EPAC 2000
in Vienna.
- DSP controlled data acquisition system for CELSIUS:
- We built a data acquisition
system to measure fast varying signals
such as tunes or Schottky signals. The System is designed around a
AD-21061 Digital Signal processor and two AD-9240 Analog-to-Digital
Converter that sample with 10 Msamples per second. We can use it in
various modes: direct spectra up to 5 MHz, normal undersampling,
zoomed-FFT mode, or direct software-based undersampling. Published
in Nucl. Inst and Methods A 441, 76, 2000.
- Schottky Diagnostics in CELSIUS:
- I worked on a program to fit physics parameters, such as energy
spread or damping rates to measured Schottky spectra. See the PAC97
proceedings.
- Resonances driven by the Electron Cooler:
- I worked out the resonance driving terms of the non-linear electric
field of the electron cooler. It's published in the EPAC98
proceedings.
- Orbit Correction in CELSIUS:
- I have written a program that iteratively corrects the closed
orbit in CELSIUS. It works both in static and dynamic mode, i.e.
when ramping the magnets. Moreover, degeneracies due to poor
placement of steering magnets or malfunctioning position
monitors are taken care of by using a Singular Value Decomposition
solver for the linear equations.
- Steering system for the proton therapy beamlines:
- In order to facilitate setting up the proton therapy beam lines
I worked on an automatic alignment system that uses a split-sector
transmission ion chambers and steering magnets to observe and
correct the position of the proton beam. The user interface for
our operators is written in Tcl/Tk.
- Inexpensive Beam Size Monitor:
- We designed a simple device we called a Sture-pin, which could equally
be called a faraday pin. It is an isolated mounted stainless steel
pin that is moved by a pneumatic piston into the beamline. When
moving the beam with a steering magnet, we can observe the current
on the pin using our normal faraday cup electronics. Plotting the
current from the pins versus the current of the steering magnet
yields nice profiles.
- Software based beam switching:
- CELSIUS only needs beam from the cyclotron while injections and while
accumulating. We developed a system to synchronize switching of
beamline magnets with cycles in CELSIUS to allow automatic delivery
of beams to parasitic users. Now this system is mostly used for
"quick-and-dirty" synchronization of devices in CELSIUS itself.
- Target beam lines for the European Spallation Source:
- I designed the beam
lines between the rings and the targets of the proposed European
Spallation Source Project.
- Interfacing GPIB Hardware to the Control Computers:
- We have a collection of diagnostic devices like spectrum/network
analyzer, digital oscilloscopes, or function/pulse generators. In
order to use these devices systematically in experiments, I have
written interface software to the control computers.
- CERN in Geneva, 93-95:
- For some time I worked on the LHC at CERN on orbit correction,
betatron coupling, and non-linear effects.
- SLAC in Stanford, 90-93:
- I used to work at SLAC on the SLC and on SPEAR where my main
fields of interest were: beam-beam interaction, orbit steering and
alignment, vacuum calculations.
- DELTA in Dortmund, 86-90:
- I received my PhD for a thesis on the Interaction between a
Free Electron Laser and a Storage Ring.