1. General presentation about recent status of DRFS
S. Fukuda (KEK)
HLRF
HLRF WebEx Meeting (Fukuda)

2. Cost difference which should be Accounted
Different Scheme of DRFS is Considering
Scheme of Diode Type Klystron and Marx Modulator or other type of modulator : System description will be shown later
Motivation – R&D of some key points takes longer time and not in time of TDR preparation
Reliable Crowbar Circuit
---- Gap switch reliability,
-----How about other device such as thyratron and ignitron?
-----Solid state switch is reliable but expensive
*Marx modulator includes this solid state switch
Cheap and compact pulse sag compensation circuit
-----bouncer circuit is reliable and successive, but need space and not easy to change the specification
Start to compare the cost of two schemes
Technically both scheme reliabilities in final version will be same degree
How about the cost difference?
HLRF
HLRF WebEx Meeting (Fukuda)

3. New DRFS Plan in Kamaboko
If DRFS design is changed from MA-klystron system to Diode-klystron system, configuration is almost the same as before. Footprint of new scheme is now under design.
Diode Klystron
Marx Modulator
2011/12/2
HLRF Webex (FUkuda)

4. PS system for Diode-type klystrons2 3
(0V)
6.6 kVAC, 3φ
VCB
Transformer
Input:6.6kV
Output:
420V,
200V,
100V
Klystron #1
Klystron #13
Marx
Modulator
Heater Trans.
Oil Tank 7 1 HK
HV cable
Heater PS H
Klystron
Heater/Cathode
HV Box #1 6 4 5
Control 8
Socket is in air
6.6kV Main Power Line
Klystron system connected to HV cables in parallel

5. Different Design of DRFS and Cost Difference
Considering the additional features of ILC scheme such as SB2009, low energy option, cavity degradation effect and so on, specification of not only DRFS but also RDR should be changed and therefore re-estimation of cost is required.
Above additional request needs the increase of HLRF cost though we should try to decrease the cost by introducing SB2009 scheme.
For DRFS, basically the scheme change gives the large effect for technical reliability for the issues mentioned before.
There are some expectations that cost may be decreased in the system of diode-type klystron and marx modulator because of its more simplicity.
Though not so simple. For example, though diode type klystron is simpler than MA type klystron but Toshiba says cost of 8000-tube manufacturing is almost the same as the first order approximation
HLRF
HLRF WebEx Meeting (Fukuda)

6. Cost Difference among the two DRFS
Discussion about the cost only in Kamaboko Tunnel
Klystrons
Including recent specification change Body design (RF circuit design) and beam optics design are the same among the DRFS diode and DRFS MA klystrons
Body design (RF circuit design) and beam optics design are the same among the DRFS diode and DRFS MA klystrons
Gun design and focusing (permanent) magnet design of diode type is simpler for diode type klystron
For 8000 manufacturing, Toshiba says both cost is not so different in the first order approximation
Other factors such as the manufacturing method and automatic process of fabrication, measurement and processing give the larger cost effects
From that view point, processing of klystron in ILC site is very important factor (which should be discussed later)
Modulator
In original plan of MA-klystron DRFS, simple DC power supply and MA modulator are considered, but thereafter additional specification such as the back-up system, the switching regulator, the crowbar, and the bouncer requires the complexity of cost and system structure.
Diode-type klystron and modulator system solves some aspects of above points.
Cost estimation is asked to SLAC and DTI now, and we will quote to other possible companies. DTI proposed Marx modulator and solid state hard switch modulator, and both cost estimation will be performed in a month. Specification and description will be performed by Akemoto.
If ambiguity come from the absence of reliable technology described before in MA-type DRFS is considered, cost of diode type DRFS is expected to be cheaper.
Power Distribution System
Recent PDS change in DRFS is to introduce circulators and variable hybrids.
These changes result in cost increase.
PDS cost estimation, there are now changes between two DRFS schemes.
Cost estimation is based on the RDR basis.
HLRF
HLRF WebEx Meeting (Fukuda)

7. Cost Difference among the DRFS and RDR
Discussion about the cost only in Kamaboko Tunnel
General
Including recent specification change described before, re-estimation is required and this results more most than the estimation of SB2009.
Klystrons
Basically DRFS klystron cost is more expensive since one RDR system contains 13 (12) klystrons and unit price of DRFS klystron is higher than the 1/13 times price of 10 MW MBK.
Target price of DRFS we pursue is to make smaller the difference among the DRFS klystron and MBK.
Basic condition of manufacturing such as in-site auto-processing of klystron will help this approach.
In 10 MW MBK, also in-site auto processing is helps the cost decrease but process is more complicated than DRFS and cost reduction effect will be smaller than DRFS case.
In diode-type DRFS, klystron socket is simple and oil-free system (is expected) and it has the benefit.
Modulator
If both types employ the Marx modulators, almost the cost will be same in the first order though the out put voltage is different ( 70 kV in DRF and 110 kV in RDR)
In the case of Kamaboko tunnel, DRFS does not need the back-up system therefore significantly the cost is the same order.
We are interesting about the solid state hard SW modulator and its price.
Cost estimation of main modulator are estimated by the company base ( and SLAC base)
KEK have a plan to introduce the cheaper modulator in STF-II and now we are preparing to have an international bit.
Power Distribution System
Recent PDS change in DRFS result in small difference or almost equal cost effect between the DRFS and RDR.
Cost difference is essentially come from the difference of klystrons. Other factors on DRFS is depend on the availability, operability and reliability.
HLRF
HLRF WebEx Meeting (Fukuda)

8. Common Understanding to Estimate the Cost of HLRF
In order to perform the cost estimation in various models in HLRF, comon understanding about the specification is important.
Cavity strings scheme in cryomodule, 989 or 888?: Common understanding is necessary, and I think 888 system should be employed.
Understanding of total overhead numbers of RF source in ML, electron source, positron source and DTML.
Overhead of klystron power considering LLRF feedback margin.: Common understanding including LLRF people to stand on the common basis of cost estimation. This will be related to the output power of klystron.
Is sorting necessary? If DRFS introduce circulator, this will be the same as KCS and discuss the common basis.
Concerning about RDR
RDR, an RDR based on single tunnel with diameter of 5.5m (4.5m) and an RDR based on Kamaboko tunnel, should be prepared, but conclusion will be discussed. Who is responsible for RDR is also the issue.
Is single tunnel with 5.7m diameter DESY type specification?
Is RDR system replaced after RFS in Kamaboko tunnel?
HLRF
HLRF WebEx Meeting (Fukuda)

9. Understanding of In-site Facility for Klystron Processing
In DRFS, Cost estimation of DRFS klystron are based on the basic condition of on-site processing.
In ILC host laboratory, several fractions of modulators are installed in advance and klystron processing will be performed automatically, and this helps lot for cost reduction in DRFS klystrons.
Extra cost investing is unnecessary in both the company and ILC in this method.
Single ILC host laboratory? A few hub-Lab?
This will be also linked to the numbers of company to order. Cost for testing person etc, will be the point of discussion.
In RDR, auto processing described above is not easy comparing with DRFS klystrons, but employing similar system is also expected to be cheaper cost estimation. And this will be also understood commonly.
HLRF
HLRF WebEx Meeting (Fukuda)