1.5-GeV FFAG Accelerator for the AGS Facility Page: 4 of 20
This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
the AGS. For instance a typical mode of operation for protons is shown in Fig. 2. In this
case, negative ions are injected into the Booster at 200 MeV, where they are stored by
charge-exchange method. The emerging positive-charged protons are accelerated to 1.5
GeV and transferred to the AGS that is initially set in a holding mode. The AGS
circumference is four times that of the Booster, so that a complete fill of the AGS
requires also four Booster beam pulses. Once the AGS is completely filled, the whole
beam is then accelerated to the top energy of about 28 GeV. Presently, the repetition rate
of the Booster is 7.5 Hz, and that of the AGS is 0.5 Hz. That requires a filling time of the
AGS of about 0.5 second, followed by about one second for acceleration to the top
energy, and another second for resetting the AGS field cycle. At best, the overall cycle
period is 2.5 seconds (excluding any flat-top for slow-spill extraction, namely only
single-turn extraction). With a typical intensity of 7 x 1013 protons per cycle accelerated
to 28 GeV, that yields an average proton beam power of about 125 kW, in the best of
conditions.
It is also to be noticed that a filling time of
0.5 sec AGS 0.5 second is actually a long period where
several effects on the stored beam may occur,
with consequent losses and size deterioration.
Booster 2 0 sec Similar considerations apply of course also to
polarized protons and heavy ions. One would
Figure 2. Typical AGS cycle for protons expect a great improvement on the beam
quality and performance if the filling time
can be shortened so that particles do not have to wait too long before they are accelerated.
The AGS Upgrade Program
It has been recently proposed [8] to upgrade the AGS facility to generate an average
proton beam power of at least 1 MW. This can be accomplished in two steps: (1) the
replacement of the main magnet AGS power supply with one operating at 2.5 Hz, and (2)
a Super-Conducting Linac (SCL) for direct acceleration of protons (actually H-) from the
200-MeV DTL to 1.2 GeV, followed by immediate transfer into the AGS, as shown in
Fig. 3. This mode of operation would completely by-pass the Booster, and eliminate the
0.5 s long injection period. The proposed new AGS cycle is then as shown in Fig. 4. With
this done, it is also reasonable to expect a significant improvement on the beam
performance (namely, stability and dimensions confinement), and a 30 percent increase
in overall intensity per AGS cycle, that is about 1014 protons (with some contingency
included). Said in another way, the shorter is the period of time the beam spends
circulating in the Booster or in the AGS, the more stable it is, and it can carry more
intensity.
A feasibility study of the 1.2-GeV SCL has already been done [9], and more engineering
design is under progress. Such a device is relatively expensive, and is also a technology
that still needs to be completely demonstrated (see for instance the SNS-SCL [10]).
Moreover, it requires an extensive men power and engineering knowledge in cryogenic
and high-gradient RF cavities. In parallel, the upgrade requirement of the main magnet
AGS power supply had been estimated, and a conceptual design of the new power supplyI
Upcoming Pages
Here’s what’s next.
Search Inside
This report can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Report.
Ruggiero, A. G.; Blaskiewicz, M.; Courant, E.; Trbojevic, D.; Tsoupas, N. & Zhang, W. 1.5-GeV FFAG Accelerator for the AGS Facility, report, February 1, 2004; United States. (https://digital.library.unt.edu/ark:/67531/metadc834676/m1/4/: accessed March 19, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.