Lawrence Berkeley National Laboratory, 88-Inch Cyclotron

 

                          

October 1999

 

 

 

 

Installation of a new emittance scanner
at the AECR-U beam transport line.

 

 

 

Scanner_Total_View.jpg (61186 bytes)

Fig.1:
The new emittance scanner head
plus vacuum spool and feedthroughs.
(click figure for enlarged picture)

 

A new emittance scanner device (Fig.1) has been installed in order to investigate the ion-optical parameters of the AECR-U injection beam line into the 88-Inch Cyclotron at higher beam-current densities. An electrostatic-deflection-type emittance scanner has been chosen to allow fast on-line measurements while tuning the ion beam through the cyclotron, because it allows very fast data-sampling. One scan takes between one and two minutes, depending on scan resolution.

 

 

Computer_with_Software.jpg (53796 bytes)

Fig.2:
The scanner computer control
at the ion source control console.
(click figure for enlarged picture)

 

 

ScannerSoftware1.jpg (255269 bytes)

Fig.3:
Software user interface to control scanner settings.
(click figure for enlarged picture)

 

A user-friendly computer control (Fig.2 and Fig.3), developed at the 88-Inch Cyclotron, processes the acquired measurement data. The scanner electronics (Fig.4) was fabricated at our electronics shop. The mechanical design of the scanner head was developed in cooperation with the Ion Beam Technology Program in the Accelerator and Fusion Research Division at Lawrence Berkeley National Laboratory.

 

 

Scanner_plus_Electronics_Rack_from_Front.jpg (57750 bytes)

Fig.4:
Electronics control rack (to the left) plus scanner head
mounted in horizontal direction (to the right).
(click figure for enlarged picture)

 

 

AECR_Pacman_Scanner_Total_View.jpg (62833 bytes)

Fig.5:
AECR-U ion source (right), mass analyzer Pacman (center, yellow),
spool with emittance scanner and subsequent Glaser lens (left, blue),
the beginning of the 88-Inch cyclotron injection beam line.
(click figure for enlarged picture)

 

The scanner is positioned after the AECR-U mass separator and its coupled diagnostic spool, which contains the mass-resolving slits (Fig. 5 and 6). For that purpose, a small bending magnet had to be removed from the beam line and replaced with the new spool for the emittance scanner device.

 

 

scanner_as_seen_against_beam_direction.jpg (58250 bytes)

Fig.6:
Scanner head shown against ion-beam direction,
located after the mass analyzer and in front of the first
Glaser lens of the 88-Inch Cyclotron injection line.
(click figure for enlarged picture)