1. Youth, Family, and Contextual Characteristics Predicting Violence Exposure: Disruptive Behavior Disorder Symptoms as a Moderator Penny S. Loosier, Michael Windle, & Eun Young Mun The University of Alabama at Birmingham A New, Robust Beam Modulation Strategy for the Q p weak Experiment Nuruzzaman (Advisor: Dipangkar Dutta) for the Q p weak Beam Modulation Team AbstractBeam Modulation OverviewCalculations Q-weak Overview Calculations We utilize the OPTIM program written by Valery Lebedev[2] to start with a pure position or angle deviation at the Q p weak target and to send tracks in the upstream direction using an inverse beamline. Because of time reversal symmetry, such a figure is an existence proof that pure modulation at the target is possible with a forward beam. Bench tests were successful. Now, we are working on controls. This new strategy for beam modulation with a pair of coils will benefit any parity violating experiment. Bench Tests Summary The simplest method to perturb an arbitrary forward beam onto the magic trajectory is to kick it with a small dipole at one of the zero crossings using inverse beamline calculations. But this approach requires zeroes which are in a region of stable, design optics, as well as upstream of our energy measurement at 3C12. Due to lack of suitable zeroes in Figure 2, we have adopted a two-coil approach. [4] 1.www.jlab.org/Qweakwww.jlab.org/Qweak 2.http://www-bdnew.fnal.gov/pbar/organizationalchart/lebedev/OptiM/optim.htmhttp://www-bdnew.fnal.gov/pbar/organizationalchart/lebedev/OptiM/optim.htm 3.Nuruzzaman, PPT, Q p weak Collaboration Meeting, 1 st Order Beam Modulation in the 3C Line 4.Personal communication with Mike Tiefenback The search for fundamental description beyond SM can be done in two ways: 1. Build increasingly energetic colliders. Or 2. High precision measurements. [1] The objective of the Q p weak experiment is to measure the parity violating asymmetry (~250ppb) in elastic electron-proton(e-p) scattering to determine the proton's weak charge with an uncertainty of 4%.[1] The e-p scattering rate depends on the five beam parameters: horizontal position (X), horizontal angle (X΄), vertical position (Y), vertical angle (Y΄) and energy (E). Small changes in these parameters will create a change in rate. If these parameters are beam helicity dependent, this will create a false asymmetry. The goal of the source group is to keep these helicity-correlated parameters as small as possible, while the goal of our beam modulation group is to measure the detector sensitivities to correct remaining false asymmetry. In order to measure the detector sensitivities, we will modulate X, X΄, Y, Y΄ using four pairs of coils in the Hall-C (3C) beamline, as well as energy using an SRF cavity. We have determined the optimal positions for the pairs of coils that will be used to modulate the beam. These results and some preliminary tests of the coils and the associated control instrumentation are discussed. References The advantages of a pair of coils over single coil: Greater flexibility in coil positioning Coil positions do not have to be changed if design optics change Beam Parameter Modulation Amplitude for 10 ppm Current through 1 st Coil I 1 (A) Field Integrals for 1 st Coil BdL 1 (G-cm) Tune Parameters (BdL 2 / BdL 1 ) X50 µm0.0268.5 X΄X΄50 µrad0.945312.0-2.52 Y50 µm-0.038-12.5-1.32 Y΄Y΄50 µrad2.88-950.0-0.465 A modulation Clock Time Required 10% DF (Hours) Clock Time Required 1% DF (Hours) Clock Time Required 0.1% DF (Hours) 1 ppm434304300 10 ppm0.434.343 To make sure that the planned hardware could provide the required field integral at frequencies of up to 500 Hz, we did the following bench tests: powered a JLab MAT(HF) coil with a Trim-II power supply at 10Hz-500Hz determined that only sinusoidal waveforms are feasible determined I max = 5A based on the observed coil temperature rise determined that Trim-II can be used reliably up to 250 Hz with 3A output measured the field integral with a GMW Hall Probe monitored the output waveform quality using a LEM current transducer drove two coils simultaneously from our FANUC VME function generator Table 3: Field integrals & calibration constant [3] Table 2: Detector sensitivity & modulation amplitude [3] Beam Parameter Single Detector Sensitivity Assumed Reduction for Whole Detector Whole Detector Sensitivity Modulation Amplitude for 10 ppm Position10 ppb/nm 500.2 ppb/nm 50 µm Angle10 ppb/nrad 500.2 ppb/nrad 50 µrad Energy1 ppb/ppb1 10 ppm (~10 keV) We then estimated the amount by which we will need to modulate the beam position and angle: For 10% statistical accuracy on, the required measurement times for a single beam parameter are: Table 1: Clock time for different statistical accuracy [3] This strongly suggests that modulations should be at least 10 ppm in order to yield useful results in a few days Angle kicks require much larger field integrals Tune parameters for position and angle are quite different Figure 2: Beam trajectory with inverse beamline [3] Target X X΄X΄ Y΄Y΄ Y Orbit excursion are ≈10 times larger for angle kicks than position Figure 3: Clockwise from upper left corner: Beam trajectory with forward beamline X, X΄, Y, Y΄, coil positioning, E [3] 1 st Coil 2 nd Coil Target 2 nd Coil 1 st Coil 2 nd Coil 1 st Coil 2 nd Coil X X΄X΄ Y΄Y΄ Y Target Compton @ 3C12 E Orbit excursion are ≈10 times larger for angle kicks than position Figure 4: Circuit Diagram and Image of Bench Test Figure 5: Clockwise from left corner: Input V~ I, Field integral for different currents, Signal from VME and LEM, Inputs and outputs from two coils rms dA dX i