Booster and AGS transverse emittance during the 2006 and 2009 polarized proton runs

Zeno, K.

Brookhaven National Laboratory (BNL) Alternating Gradient Synchrotron

关键词: Protons;    Alternating Gradient Synchrotron;    43 Particle Accelerators;    Shutdown Alternating Gradient Synchrotron;    Efficiency;   

DOI  :  10.2172/993468
RP-ID  :  BNL--94315-2010-IR
RP-ID  :  DE-AC02-98CH10886
RP-ID  :  993468

美国|英语

来源: UNT Digital Library

【 摘 要 】

This note is an overview of issues relating to transverse polarized proton emittance in the Booster and AGS. It also compares the transverse emittance during the FY09 polarized proton run with it during the FY06 run as several changes were made for the FY09 run in an attempt to reduce the transverse emittance coming out of the AGS. The FY06 run is used for comparison because it was relatively long, and it's believed that the performance of the injectors for polarized protons, up until FY09, was best during that run. Over the shutdown just before the FY09 run work was done in LEBT and MEBT to reduce the emittance coming out of the Linac. Measurements of the beam coming out of Linac1 indicate that the horizontal normalized emittance was reduced from 11.0 {pi} to 4.5 {pi}mm mrad, and that the vertical normalized emittance was reduced from 12.1 {pi} to 5.5 {pi} mm mrad going from FY06 to FY09. There were 2 new types of stripping foil installed in the Booster, called descriptively the 'strip' (No.6) and 'stamp' (No.2) foil, both nominally 100 {micro}g/cm{sup 2}. Both foils are composed of a diamond like material, and designed to reduce the number of times the beam goes through the foil. Other than those, there are two standard 100 {micro}g/cm carbon foils (No.3 and 5), and one 200 {micro}g/cm{sup 2} carbon foil (No.4). Of the two 100 {micro}g/cm{sup 2} foils, one has shown some deterioration (No.3) in stripping efficiency. During the FY06 run a standard 100 {micro}g/cm{sup 2} foil was generally used, and during the FY09 run the strip foil was generally used, though the stamp foil was also used for the last 3-4 weeks of the run. Both the FY06 and FY09 runs were about 5 months long, starting in late January, FY06 ending in late June, and FY09 ending in early July. A new injection setup was used for about the last 3 months of FY09, from the beginning of April to the end of the run. This setup uses 1/2 integer stopband correctors with the tunes near, but slightly greater than, 4.5 to distort the {beta} functions at the foil in order to reduce the emittance blowup caused by scattering on the foil. New BtA quad settings, largely based on a MAD model of the BtA line and AGS were used for virtually the entire FY09 run (Feb 5 to the end) in an attempt to improve the matching into the AGS. Since, it has been thought for some time that there is emittance blowup in the vertical due to an injection mismatch. The nominal Linac pulse width was decreased from 400 {micro}s to 300 {micro}s in the latter part of february 09, so the vast majority of the FY09 run used a 300 {micro}s pulse width. The standard pulse width for FY06 was 400 {micro}s. This has some implications for comparing the data from FY06 with that from FY09, but they don't seem insurmountable.