Photoinjector design for the LCLS

The design of the Linac Coherent Light Source assumes that a low-emittance, 1-nC, 10-ps beam will be available for injection into the 15-GeV linac. The proposed rf photocathode injector that will provide a 150-MeV beam with rms normalized emittances of 1 mm in both the transverse and longitudinal dimensions is based on a 1.6-cell S-band rf gun that is equipped with an emittance compensating solenoid. The booster accelerator is positioned at the beam waist coinciding with the first emittance maximum and is provided with an accelerating gradient of ~25 MeV/m, i.e., the "new working point." The uv pulses required for cathode excitation will be generated by tripling the output of a Ti:sapphire laser system consisting of a highly stable cw mode-locked oscillator and two bow-tie amplifiers pumped by a pair of Q-switched Nd:YAG lasers. The large bandwidth of the Ti:sapphire system accommodates the desired temporal pulse shaping. Details of the design and the supporting simulations are presented.Comment: 13 pages (double spaced), 4 figures, contributed to The 23rd International Free Electron Laser Conference, Darmstadt, Germany, 20-24 August 200

The PHENIX Experiment at RHIC

The physics emphases of the PHENIX collaboration and the design and current status of the PHENIX detector are discussed. The plan of the collaboration for making the most effective use of the available luminosity in the first years of RHIC operation is also presented.Comment: 5 pages, 1 figure. Further details of the PHENIX physics program available at http://www.rhic.bnl.gov/phenix

Determinants of the Accounting Change for Income Tax

This study examines determinants of the decision of New Zealand firms to change their income tax accounting method from comprehensive to partial allocation. New Zealand provides a unique setting to investigate this issue because it allows firms the choice to use either the comprehensive or partial allocation procedures to account for income tax. I find that efficient contracting and debt-related opportunistic factors are both important determinants that influence firms' decisions to change to partial. Specifically, the results indicate that the change is related to the extent of investment in depreciable assets and the closeness of firms to their debt covenant restrictions. Copyright Blackwell Publishers Ltd, 2005.