UKNF WP1: Conceptual Design

1. UKNF WP1: Conceptual Design Status Report, Jan 2006 C.R. Prior

2. Work Progress • Proton Driver • Work on pulse structure • 10 GeV FFAG driver (GHR) • Pion decay/Muon capture • Continued optimisation (SJB) • Muon cooling • Development of tracking techniques and absorber models (SJB) • Acceleration • New FFAG modelling code (SM) • Muon Storage Ring • Isosceles triangle design • Detectors • Geometric ring layouts

3. Non-isochronous FFAG 4 MW Proton Driver • RAL design • 5 bunches per pulse • 50 Hz repetition rate • 10 GeV • Isochronous FFAG with insertions

4. ≥ 22.43° Neutrinos Neutrinos ± injections End bend Collimation, rf and tune change Muon Storage Ring Designs for 20 and 50 GeV to fit in same tunnel

5. Triangle Ring Details • Isosceles triangle ring, designed for MW intensities • Includes a beam loss collection system for muons. • Combined (not separated) function magnets in arcs. • Solenoid focusing in the two production straights. • Use bend units at the ends of the production straights. • Matching section bends to suppress dispersion • Lattice is modified when upgrading from 20 to 50 GeV. • Change some magnets • re-align ring.

6. Muon Beam Loss Collection • Owing to the e±losses after ±decays, the warm bores of S/C arc magnets have to be cooled & clad with Pb. • cladding absorbs > 80% of the e±beam power • Direct ± wall loss also leads to magnet heating • To minimise this, use a ± loss collection system • Primary and secondary collimators in 4 FODO cells at the centre of the short straight section of the ring • Primary collimators are set for: βγA = 30 ( mm r). • Ring acceptances are: βγA = 30 (1.5)2 ( mm r).

7. Production Straight Focusing • A figure of merit for the focusing in a lattice is: 1 / (γβmax ) • For equal γ (beam angles), a solenoid system has a 50% lower value for βmax. • Design uses eight 4m solenoids in 300.8 m straights: • At 20 GeV, βmax ≈ 97 m for solenoids with 4.3T • At 50 GeV, βmax ≈ 162 m for solenoids with 6. 4T

8. 20 GeV Lattice Functions (Excluding Production Straights)

9. Storage Ring Parameters

10. Injection of n Trains of 80 ±Bunches Long neutrino production straight section . Solenoid 1 Solenoid 2 Solenoid 3 Injection septum Train of 80,  or  bunches Fast kicker magnets, K Superconduc-ting solenoids Stored energy/power of kicker magnets is large owing to the big acceptance and the ~370ns rise and fall times for the 1170.8 m circumference ring, which has n (= 5) injected bunch trains per 50 Hz cycle. Induction kickers may be needed for the upgrade to 50 GeV.

11. Design Summary • An outline design has been made for two isosceles triangle, 20 (potentially 50) GeV, ±storage rings. • Angles of the triangle depend on ring and target sites. • The MW rings have large βγA, at 30 (1.5)2 ( mm r). • Smallest circumference C = 1170.8 m (straights = 300.8 m). • CERN equilateral ∆, C = 2074.8 m & US1, C =1752.8 m. • Production straight solenoids give lower beam sizes. • Uncooled (45  mm r) ±beams appear impractical. • Dynamic aperture tracking is to being carried out by F. Meot.

12. Alignment and Orientation of Muon Ring • 6 possible NF sites • RAL, CERN, JPARC, BNL, FNAL, ORNL • 17 possible detector sites • Ascertain which NF site might be suitable for an isosceles ring that directs  to two detectors • Identify possible green field site for second detector, having chosen a first. • What base lines are required? • 700/3000/7500 km?