Possible Damping Ring Timing
Kazuro Furukawa
Injector Linac, KEK<kazuro.furukawa@kek.jp>

Some info at <http://www-linac.kek.jp/cont/epics/event/>
Conference papers at <http://www-linac.kek.jp/linac/>
Injector Linac Upgrade towards SuperKEKB

K.Furukawa, KEK, Jun.2016.

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DR timing

Bucket selection in Phase-2 with DRu Without DR, simply wait up to 5120 x 96 ns ~ 490 μsv 96 ns : highest common frequency between linac – ringe− GunKEKB

ARCe+ BT (3.5GeV, 0.6nC)

Primary e– (3.5GeV, 10nC)
e+ Targetu With DR, in order to select arbitrary bucket in MR, have to wait up
to ~4.5 ms, even if a bucket in DR was carefully selectedv Power supply can wait only 2 ms, one of only 2798 buckets in 5120 buckets can beselected, may have to change LLRF condition at latter half of linac every pulse
96ns +e DR (1.1 GeV, 4nC)
>100nse− GunARC
Primary e– (3.5GeV, 10nC)>100ns
96ns

SuperKEKB
e+ BT (KEKB: 4GeV, 4nC)

e+ Targetv Can be a big challenge in LLRF precisionInjector Linac Upgrade towards SuperKEKB

K.Furukawa, KEK, Jun.2016.

2Memo from Oct.6.2016u 32k 周 14ms 分記録
u 読み出しは 12 枚で 0.5秒
u 2ns または 4ns stepu Bunch 同期信号、入射 Kicker を打ってから Revolution で Timing を打ち続けるv 20% の Duty 比、TTLv 入射 Kicker が打ったらそれに同期する、つまり 2 pulse 溜めたときには、最初の pulse は無視³ ???

u Start 信号、入射 Kicker から、(NIM)/TTLu さらに Revolution を一ヶ所 2 種類v 一つは MR RF から作った DR Revolution と DR RF から作った DR Revolution の 2 つv 入出射 Kicker / BPM EVR で一方の Revolution を作れば良いv 15 slot VME64x x2箱u Dispersion 測定のために 509 MHz を振るv +/- 50kHzu そのため、Linac 同期の 509 MHz/Revolution は使えないu おそらく Main event system とは切り離したv Event system または新規開発信号分配 System が必要

u Dispersion 測定後に出射 Kicker を同期できるか不明
v その場合はその独立 Event System 側が出射 Kicker を打つ
v Kicker 側は 親 Event system と独立 Event system の双方から Kicker signal を受ければ良い
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Distributed bus and multiplexed countersu The distributed bus allows transmission of eight simultaneoussignals with the event clock rate time resolution (10 ns at 100 MHz
event clock rate). The source for distributed bus signals may comefrom an external source or the signals may be generated with
programmable multiplexed counters (MXC) inside the eventgenerator.
The distributed bus signals
may be programmed to beavailable as hardware outputs
on the event receiver.

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MXC and Sequenceru The end sequence code 0x7f resets thesequencer RAM table address and timestamp
register and depending on configuration bits,
disables the sequencer (single sequence,
SQxSNG=1) or restarts the sequence either
immediately (recycle sequence, SQxREC=1) orwaits for a new trigger (SQxREC=0).

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5Injector Linac Upgrade towards SuperKEKB

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Pulse-to-pulse modulationu Four PPM virtual accelerators
for SuperKEKB project

Event-based
Control System

Every
20 ms

F.B

Based onDual-tier controls withEPICS and event-systeme− GunARC

Independent parameter setsfor each VA (20ms)>200 parameters
for equipment controls
many morefor beam controls
maybe with additional PPM VAof stealth beamfor measurement

F.B

PF Injectione– (2.5GeV, 0.2nC)

F.B
e− GunARC

Damping ring

F.B

SuperKEKB-LER Injectione– (3.5GeV, 10nC)

F.B

e+ Targete+ (4GeV, 4nC)

e− GunARC

SuperKEKB-HER Injection

F.B

e– (7GeV, 5nC)
e− GunARC

F.B

PF-AR Injection

F.B
e– (6.5GeV, 5nC)

Injector Linac Upgrade towards SuperKEKB

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