1. March 30, 2004 TJR1 MICE Target Source Calculations Tom Roberts Illinois Institute of Technology March 30, 2004

2. March 30, 2004 TJR2 Outline of Computation Select beamline tune, determine an enclosing target acceptance (P min, P max, x’ min, x’ max, y’ min,y’ max ) Use LAHET, MARS, and g4beamline (Geant4) to determine pi+ that enter the target acceptance per proton on target Use g4beamline to generate 20M pi+ into the target acceptance, and determine how may good mu+ they produce. Model the ISIS beam and target to determine the rate of protons on target. Put the above values together to determine the absolute rate of good-mu+/millisecond.

3. March 30, 2004 TJR3 Target Acceptance (JAN04 tune) ParameterValue P min 300 MeV/c P max 400 MeV/c x’ min -0.035 x’ max 0.035 y’ min -0.015 y’ max 0.015

4. March 30, 2004 TJR4 Target Particle Production ParticleLAHETMARSGeant4 pi-3.2E52.8E5 e-4.6E31.5E4 e+01.6E4 gamma7.0E55.6E5 pi+7.8E51.1E69.7E5 n7.2E64.1E6 p3.7E56.2E63.6E6 Particles into acceptance per millisecond of good target.

5. March 30, 2004 TJR5 Model of Target and ISIS Beam ParameterValue Protons in Bunch2.5E13 Bunch Frequency1.5 MHz Good Target & Good RF Duty Factor 0.001 Beam Radius37.5 mm Target Area2 mm 2 Beam Area4418 mm 2 Beam Density Factor*0.1 Protons/sec on Target1.4E12 * Estimate of: (beam density at target)/(average beam density)

6. March 30, 2004 TJR6 Results Normalization Program Good mu+ per ms LAHET304 MARS419 g4beamline375 Major Variables: Beamline tune can vary rates by a factor of ~6 (tuning for lower input emittance yields higher good mu+/proton) Target dip height directly affects protons on target (must keep ISIS losses within bounds) JAN04 tune, 6π mm-rad input emittance, no LH2, no RF. Because of the large variations in yield for different tunes, and the need to keep ISIS losses to a minimum, an easily- adjustable insertion depth for the target is essential.