Insertion devices

The insertion Devices (ID) group is responsible of design, development and operation of Insertion Devices for the different beamlines at MAX IV Laboratory. Each beamline is fed by insertion device, undulator or wiggler, which consists of an array of permanent magnets that provide an alternating static magnetic field that forces the electron beam to oscillate and thus radiating photon beam. The different ID’s cover photon energy range from VUV to hard X-rays at the three accelerators at MAX IV, the low emittance 3 GeV ring, the 1.5 GeV ring and the 3 GeV linear accelerator as a source for short pulses.

1. Out-of-vacuum undulators for VUV and Soft X-rays production. It consists of six APPLE II undulators built in-house, one APPLE II and one planar undulators transferred and refurbished from the MAX II ring.
2. In-vacuum undulators (IVU) and wiggler (IVW) for hard X-rays production. Six IVU’s and one IVW at the 3 GeV ring and two IVU’s at the Short Pulse Facility (SPF).

Accelerator	Beamline name	ID Type	Period Length [mm]	Length [m]	K-eff value	Gap [mm]
3 GeV ring	BioMAX*	IVU	18	2	2	4.2
3 GeV ring	NanoMAX*	IVU	18	2	2	4.2
3 GeV ring	HIPPIE**	APPLE II	53	4	3.35	11
3 GeV ring	Veritas**		48	4	3.35	11
3 GeV ring	Balder***		50	2	9	4.5
3 GeV ring	CoSAXS*	IVU	19.3	2	2.2	4.2
3 GeV ring	DanMAX*	IVU	16	3	1.66	4
3 GeV ring	SoftiMAX**	APPLE II	48	4	3.35	11
3 GeV ring	ForMAX*	IVU	17	3	1.85	4
3 GeV ring	MicroMAX*	IVU	18	3	2.0	4.2
1.5 GeV ring	Bloch**	Q-APPLE II	84	2.6	8.65	14
1.5 GeV ring	FinEstBeAMS**	APPLE II	95.2	2.6	10.4	14
1.5 GeV ring	SPECIES****	APPLE II	61	2.6	4.85	16
1.5 GeV ring	MAXPEEM**	APPLE II	58	2.6	4.89	14
1.5 GeV ring	FlexPES****	Planar	54.4	2.6	4.2	16
SPF 3 GeV linac	FemtoMAX*	IVU	15	5 x 2	2.2	2.2

*) Built by industry, In-Vacuum Undulators
**) Built in-house, APPLE II
***) Built by a collaboration with SOLEIL synchrotron
****) Transfer from MAX II ring, refurbished and characterized at MAX IV ID magnet lab

The Quasi-APPLE II undulator for BLOCH beamline at the 1.5 GeV ring	The FemtoMAX undulators at the SPF hall
The SoftiMAX undulator during magnetic tuning	Magnetic arrays of the BioMAX In-vacuum undulator

The near term R&D of the Insertion Devices at MAX IV consist of:

1. Compact APPLE X undulator with a round aperture for the generation of Soft X-ray. A cost-effective solution compared to the existing APPLE II and provides full polarization control with constant effective K-value as a function of phase, i.e. polarization state. The APPLE X is an ideal source for the proposed soft X-ray FEL at MAX IV and gives the possibility to extend the energy range below 2 keV at the FemtoMAX beamline at the SPF. In addition, it offers higher energy range with full polarization tunability at the 3 GeV MAX IV ring compared to the APPLE II undulators.
2. Short period Cryogenic Permanent Magnet Undulator CPMU for future hard X-rays beamlines. Period length of 10 – 13 mm and physical gap in the range of 3 – 3.5 mm to extend the hard X-rays range beyond 50 keV with high brilliance >10¹⁹ ph/sec 0.1% BW mm² mrad² at the 3 GeV MAX IV ring.

Magnetic Measurement Laboratory

The ID group is responsible also of magnetic measurements laboratory at MAX IV. The lab is used for in-house development, construction and characterization of ID’s, which is a key tool to meet the tight requirements of the MAX IV accelerators on the ID’s field quality. The magnetic measurements systems consist of the following;

1. Hall probe bench which covers 5.5 meters of magnetic length and a high speed on-the-fly local magnetic field measurements.
2. Stretched Wire system for ID’s field integrals measurements and single magnet block characterization.
3. Flip coil system for ID’s field integrals measurements.
4. Pulsed Wire System for local field measurement of closed-structure ID’s, like an IVU or APPLE X, and ID’s field integrals measurements.

The magnetic measurement lab is also equipped with the required infrastructure for IO and motion tests for the ID’s to minimize tunnel access during ID’s installation.

Overview of the ID Magnetic Measurement Laboratory	Two laser beams for vibration detection at the Pulsed Wire System