Electromagnet Wiggler Assembly
The IPR-FEL uses an electromagnet wiggler. Initial
studies were carried out using hand-made small period wiggler in order
to study the fucussing properties of the wiggler. Based on the studies
of the 5-period wiggler, a 20 period wiggler was designed and fabricated.
This wiggler field profile was mapped and then the system integrated with
the REB device.
20-Period wiggler : beam propagation and FEL output results
Image of 20 and 50 period electromagnet wiggler.
Another image of the 50-period wiggler showing the entrance slit and the pole adjustment screws.
The 50-period wiggler was built with offset-pole configuration in order to assist beam transport. The offset poles provide an additional magnetic field gradient along the edges of the wiggler hence providing a focussing along the x-plane of the direction of propagation of the beam.
Close-up Image of the offset pole configuration
The wiggler parameters are listed in the table below.
20-Period wiggler : beam propagation and FEL output results
Image of 20 and 50 period electromagnet wiggler.
Another image of the 50-period wiggler showing the entrance slit and the pole adjustment screws.
The 50-period wiggler was built with offset-pole configuration in order to assist beam transport. The offset poles provide an additional magnetic field gradient along the edges of the wiggler hence providing a focussing along the x-plane of the direction of propagation of the beam.
Close-up Image of the offset pole configuration
The wiggler parameters are listed in the table below.
| Type | Planar Pulsed Electromagnet |
| Number of Periods | 50 |
| Wiggler period | 10 mm |
| Gap | 8 mm (fixed) |
| Conductor | Electrical Grade Copper |
| Dimensions | 507.5 × 80 × 15mm |
| Pole Pieces | M6 CRGO strip stack (0.3mm x 7nos.) |
| Dimension | 70 × 15 × 2.5 mm |
| Max. current through wiggler | ~ 18 kA |
| Max. Peak field at wiggler centre | 1 to 3.0 kG @ 0.16Gauss/ampere |
| Pulse width | 300 µsec |
| Waveguide dimension (Outer) |
525 × 52 ×
7 mm |
Field mapping of the 50 period wiggler has been
completed and the initial beam propagation studies have been completed.
Results of the magnetic field mapping of the 50-period electromagnet wiggler.
The edge field profile of the offset-pole configuration
The support structure and vacuum chamber for the 50-period wiggler
Results of the magnetic field mapping of the 50-period electromagnet wiggler.
The edge field profile of the offset-pole configuration
The support structure and vacuum chamber for the 50-period wiggler
Permanent Magnet
Wiggler Assembly
A 15-period permanent magnet wiggler was designed
and fabricated in collaboration with the
University of Pune
, FEL lab. This wiggler system needed a total change in
structural design in order to be integrated with the existing
REB system at IPR.
A new supprt structure and vacuum beam transport waveguide have been designed and fabricated. The field mapping using Hall probe has been completed and initial experiments for field mapping using pulsed-wire method have been initiated. This wiggler is slated to be integrated with the REB once the experiments with the 50-period wiggler have ben completed.
A new supprt structure and vacuum beam transport waveguide have been designed and fabricated. The field mapping using Hall probe has been completed and initial experiments for field mapping using pulsed-wire method have been initiated. This wiggler is slated to be integrated with the REB once the experiments with the 50-period wiggler have ben completed.
The main parameters of the permanent magnet wiggler
are listed in the table ;
| Type | Planar Halbach |
| Magnet Type | Nd-Fe-B |
| Br of magnet | 11 kG |
| Wiggler Period | 2.6 cm |
| Number of periods | 15 |
| Wiggler gap |
10 - 20 mm |
| By for 7mm gap |
6.8 kG |
| By for 12mm gap |
3 kG |
| Waveguide dimension (outer) |
45 × 10 mm |
Page designed and maintained by Dr. Ravi A.V Kumar.
Last updated on 1-Mar-2002.
Please e-mail comments and questions regarding this
page to Dr. Ravi A.V. Kumar.