Near-ideal emittance exchange at the Fermilab Photoinjector
The A0 Photoinjector at Fermilab is presently home to an emittance exchange (EEX) experiment. The emittance exchange beamline consists of a 3.9 GHz normal conducting deflecting mode cavity flanked by two doglegs. Electron bunches with charges of 250 pC and energy of 14.3 MeV are routinely sent through the exchanger. Here we present results of a 1:1 transverse and longitudinal emittance exchange. The advent of synchrotron radiation light sources and free electron lasers (FEL) has been a boon to a wide range of disciplines, resulting in a constantly increasing demand for brighter sources and better resolution. This demand translates to requirements on the properties of the underlying electron beams which produce the light. In particular, one is driven to find ways to precisely manipulate the phase space volume of the beam to optimize it for the desired application. Motivated by the FEL requirement for a small transverse emittance, Cornacchia and Emma developed a transverse/longitudinal emittance exchange concept using a deflecting mode rf cavity located in the dispersive section of a magnetic chicane. This method however, contained residual couplings between the two dimensions, leading Kim to propose a modified version which removed that coupling and resulted in a complete exchange. In this configuration, the deflecting mode cavity is placed between two magnetic doglegs thereby removing the afore-mentioned coupling term. We have used this beamline with upgraded diagnostics to measure a near-ideal 1:1 emittance exchange.
- Research Organization:
- Fermi National Accelerator Laboratory (FNAL), Batavia, IL
- Sponsoring Organization:
- DOE Office of Science
- DOE Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1013743
- Report Number(s):
- FERMILAB-CONF-11-109-AD
- Country of Publication:
- United States
- Language:
- English
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Transverse to longitudinal emittance exchange beamline at the A0 photoinjector
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