1. Technical Feasibility of Anti-DID Coil
Christophe Berriaud

2. What is the Specification of the anti DID ?
Crossing angle variation;
Spin alignment;
Uniform central field for TCP;
Independent from the main field;
No field variation/adjustment needed;
Low energy pairs extraction…
…Into the outgoing beam pipe;
Winding radiation resistant.
Andrei Seryi, Takashi Maruyama
Brett Parker

3. Anti DID version 1
F.Kircher, O. Delferriere, L. Scola, M. Lemke, A. Petrov, K. Sinram, U. Schneekloth, R. Stromhagen, B. Curé, K. Elsener.

4. Anti DID version 1 Data: J= 40 A/mm²; I=615 A;
Insulated conductor dimensions 4,8*3,2 mm²
Internal radius 4.19 m;
3 cm of aluminum mandrel thickness (15 t) ;
50 km of non standard conductor (5 t);
Non existing winding machine;
Dedicated tools at each manufacturing steps;
Cost range M€. 3m
12m
Brett Parker
Useful length = 3 m
Return path = 12 m
35 mT on the axis for 2 T on the conductor
So it is an inefficient winding (20 t for 35 mT)
Wire co extruded in an Aluminum matrix
Wire in channel (Aluminum or copper)

5. Smaller Anti DID
Other winding to reduce the low energy back-scattering particles B B
Standard dipole or if you need more complexity a
Conical active shield dipole

6. Conical Anti DID In order to limit the detector dark zone:
Canted conical dipole…

7. Copper dipole ?
With a small magnetized low field diameter copper magnet can be done…
Parameters
value
unit
Inner Diameter
0.1 m
Length 1
∫ Bdℓ
0.05
T.m
Bcenter T
Energy
62.5 J
Current density 6
A/mm² Δr 25 mm
Results
Winding weight 14 kg
Joule heating 12
kW / dipole
Head force in 4T
318
If such king of dipole is compatible with the need it will be much less expensive.

8. Summary
The anti DID magnet (version Kircher 2013) is a very large magnet for a very small useful magnetic field.
The question is not “Can we built it?” but “Do we need this investment or a cheaper solution is acceptable?”.
The cost will be larger than two small magnets even superconducting one with their independent cryostat.
A precise specification of the anti DID requirements is required to go further in design and then after in technological solution choice.