Milestone M4.3
Comparison of NC and SC RFQs

Performance and Cost Data of the Superconducting RFQ Solution
With the goal of comparing the above presented solution with the one with NC RFQ’s prepared by Munich -Frankfurt, table 6 lists the main performance parameters (energy, transmission and emittance of the heavy ion beam) and an evaluation of the cost of the main components.  Moreover, the mains power gives an indication about the operational cost of this part of the RNB accelerator.
These values are compared with the equivalent ones proposed by Munich-Frankfurt on the fully NC option.

Table 6 – Beam parameters summarized, together with a preliminary cost estimate of the components

 
Superconducting RFQ
Normalconducting RFQ

NC-RFQ
MEBT
S-RFQ
Total
RFQ1
RFQ2 
Total
Transmission [%]
100
100
99,9
99,9
99,6
99,6
99,4
T increase [%]
2,5
 
12
15
5
5
10
L  [MeV deg]
0,063
 
0,069
0,069
 0,078
 0,078
 0,078
Final energy [keV/A]
88
88
560
560
319
560
560
Length [m]
2,93
1,15
2,07
6,15
3,9
3,9
7,8
Structure cost [k€]
348
450
624
1422
470
470
940
RF/PS cost [k€]
276
210
120
606
1000
1000
2000
Vacuum Equipment cost [k€]
15
90
50
155
35
35
70
Equipped cryostat [k€]
 
 
350
350
 
 
0
Cryogenic lines [k€]
 
 
120
120
 
 
0
Power at mains [kVA]
42
10
60
112
95
95
190
Total Price [k€] VAT incl.
639
750
1264
2653
1505
1505
3010


The general comments by INFN-LNL on the so called S-RFQ solution are the following:

1. Despite a possibly higher degree of complexity, the S-RFQ option needs no prototyping, being the NC-RFQ a simplified version of the one proposed and being built for Spiral2 and the S-RFQ very similar to the one working reliably in PIAVE at INFN-LNL;  on the other hand, experience with CW 4-rod RFQ with high transmission is still limited
2. A reliable comparison of capital and operational costs implies a more careful exercise:  at this stage the S-RFQ option is 20% cheaper
3. Transverse emittance is comparable, and final transmission is very close to 100% in both cases.   Longitudinal emittance …
4. Power at mains, including the budget of cryogenics in the SC option, is smaller by a factor 2 in the SC case
The overall length is larger in the NC case, but not dramatically

Therefore, at this stage of development, both RFQ solutions appear feasible, with the following remarks:

Proof of the operation of superconducting resonators on a 30 kV (S-RFQ solution) should be demonstrated before the solution can be declared to be fully feasible;
The reliable high power operation of a 4-rod N-RFQ should be demonstrated, before the N-RFQ solution be declared to be fully feasible.