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[ILC-Asia WG3] Minutes of the meeting

Here is the minutes of the 17th ILC WG3 meeting.

17th ILC Asian WG3 
Date  : May 18
Time  : 15:00-17:00
Place : KEK 3rd building 7th floor meeting room 

IPPAK (ILC Positron Project At KEKB) status         KURIKI Masao

	  Current status of IPPAK is presented. The radiation safety
	  investigation was performed by the radiation science
	  department of KEK. According to the result, the experiment
	  does not break the radiation safety regulation, but the
	  radiation flux will be increased at some direction with a
	  large magnitude (1E+4). It can be decreased by inserting the
	  target into the dump pipe (30cm from the entrance) down to
	  4.6 times. With this condition, the total flux of the
	  experiment in a reduced version, will be 0.94 of that of the
	  normal dump. The target activation is also qualified. The
	  material is activated so much, but with a carefull material
	  handling and assume 1 hour cooling down time after each
	  shot, total dose at the finger is expected to be 0.1uSv.

Electron cloud head-tail instability        OHMI Kazuhito

	 Threshold of the head and tail instability induced by the
	 elctron cloud in the positron damping ring was discussed.  By
	 an analitical aproach, the threshold is proportional to the
	 motion frequency and inversely proportional to K and Q value
	 of the oscillating motion. If K and Q were constant, the
	 threshold will be proportional to the total current, that
	 does not make any sense. If K and Q were similar current
	 dependence as the frequency, the threshold becomes inversely
	 proportional to the total current, that is consistent to the
	 experimental result. According to the experiment in KEKB, the
	 threshold depend on the average current, rather than the
	 bunch current.

WG3 related part of WG1 discussion issue towards Snowmass   KUBO Kiyoshi

	 ILC parameter related issue which should be discussed prior
	 to Snowmass was presented. The main effort in Snowmass will
	 be discussion to make a baseline design. In this view, kicker
	 study and IPPAK will be big contributions. 

DR study framework towards Snowmass

         DR study framework was presented. It was formed by the
	 discussion among the conveners and others based on the
	 Wolski's three step aproach. To organize many studies which
	 are required to determine the baseline configuration, task
	 forces for each study item are being formed. Eanch task force
	 is led by co-leaders who have responsibility to manage the
	 task force.

	 In the discussion, it was pointed out that some management
	 over or among the task forces is necessary. For example, if
	 some serious difficulty was found on a DR design, this design
	 could be removed from the list at that moment to save our
	 human resource. The over manegement have to make such
	 decision, or at least, lead such discussion.

Asian WG3 Action plan towards Snowmass

        Action plans towards Snowmass was discussed. We have several
	projects in the framework of the ILC WG3. Assuming results of
	these studies, possible insistences on the base line design of
	the ILC injector are discussed.

	The kicker experiment at ATF can determine the primary (or
	shortest) bunch spacing, which is one of the most important
	parameter of the DR design.

	IPPAK(ILC Positron Project At KEKB) can make a significant
	impact on the positron production scheme.

Reported by KURIKI Masao