Timing SystemHiroshi Kaji2

Injec5on Control
Main Trigger Sta/on performs injec/on control with following three key items.
Large Area Control:‐ control whole hardware along 600m beamline‐ farthest is injec/on point of Main Ring ~ 1000m

Timing Synchroniza/on:‐ all func/ons must be synchronized with each other‐ also with /ming of injec/on RF‐bucket

Pulse‐to‐Pulse Modula/on:‐ more than 150 of LINAC parameters must be changed‐ for “simultaneous” top‐up ﬁlling into more than one ring.

All of them are realized with Event Timing System.

3

Pulse‐to‐Pulse Modula5on

Top‐up opera/on for 4 rings “simultaneously” with only one Linac
Switch beam types and direc/ons in 50Hz
Change >150 of Linac parameters in 50Hz

4New requirements for SuperKEKB
Newly constructed Damping Ringis used for positron injec/ons.

e− GunARC

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

e+ Targete– BT (SuperKEKB: 7GeV, 5nC)

Followings are needed for positron injec/on
Longer than 40ms control‐ Positron damping is implemented at least 40ms.
‐ En5re process takes more than one injec5on period.

Electron injec/on during positron damping
Control 1st and 2nd halves of Linac separatelye– Gun ⇒ DRDR ⇒ MR

(1st half)(2nd half)

Bucket Selec/on by the Event Timing System‐ Delay 5me for 5ming adjustment to select RF‐bucket.
‐ (Note, it is produced by the dedicated modules at KEKB.)

5Timing adjustment for Bucket Selec5on
Injec/on RF‐bucket is selected “on the careful considera/on” in eachpulse.
It is for equalizing all bunch‐charges. (only for KEKB main ring)
Selec/on of injec/on RF‐bucket is:‐ adjustment of injec5on 5ming‐ speciﬁcally, adding delay 5me to standard 5ming

MR（5120 bucket）

508.9MHz

Linac/BT
RF:2856MHz

Injec/on /ming decides
injec/on RF‐bucket.

Injec/on /ming:
KEKB revolu5on/49/23 (standard 5ming) + delay
Delay:‐ varying within 0‐493µs for KEKB and SuperKEKB HER in unit of 96.3ns,‐ and within 0‐11.34ms for SuperKEKB LER.
⇒ RF‐bucket for both damping and main rings are controlled.

6New conﬁgura5on of Event Timing System
Main Trigger Sta/on (MTS)
TTL

KEKB

Main Rings

EVG

Damping Ring

Event

New design at MTS‐ # of EVGs: 1→3‐ Two‐layers conﬁgura5on‐ Two EVGs in lower‐layer

Three EVGs are operated
in independent sequenceswith diﬀerent periods.

EVR

PF‐ARPF

EVG

Realize complicated 5ming
control for SuperKEKB.

EVG

SH_A1
KL_B5/B6

SB_B

Injec5on

SB_A

e− GunARC

Cont‐ABC
SB_C

KL_51/52
SB_1

SB_2

SB_3

SB_4

SB_5

e– BT (PF: 2.5GeV, 0.2nC)
e– BT (PF‐AR: 6.5GeV, 5nC)
e+ BT (SuperKEKB: 4GeV, 4nC)

e+ Targete– BT (SuperKEKB: 7GeV, 5nC)
Cont‐1

Cont‐2

Cont‐3

Cont‐4EVRs

Cont‐57

EVG sequence and schedule for Event delivering
Coincidence of AC 50Hz
and KEKB revolu5on/49/23

Time Chart ofEvent Timing System Opera/on

EVG

Sequence of ~2 sEventUpper‐layer EVG

Trigger

MTS IOC

Timing Event for e–
Prepara5on Event for e–
Timing Event for e+
Prepara5on Event for e+
20 ms period

EVR

Middle‐layer EVR
TriggerEVG

1st half ofLinac

2nd half of
Linac

Lower‐layer EVG

Local EVR

Trigger

EVG

Local hardware
Delay value for Bucket
Selec/on8Modules
Main module:
MRF’s VME‐type modules‐ VME‐EVG‐230 and VME‐EVR‐230‐ Knowledge and experiences in the KEKB project‐ Already installed at the Linac beamline
Par/ally:
Plan to use SINAP module at Damping Ring
‐ EVO can work as both EVG and EVR‐ Equivalent performance in terms of /ming precision

Opt. FOUT

EVG
EVR

CPU

EVR & LLRF

9Current Status
Current System

New system is installedat Main Trigger
Sta/on.
EVRUpper‐EVG

Lower‐EVG

New System

Main Trigger Sta/on
We plan to be redundant Event Timing System‐ current working system‐ new developed system
for further studies and smooth taking over
Event FOUT
Modules for tests (will be removed)
will be placed.

Feasibility study for new
conﬁgura5on
Precision of output TTL is measured anddiscussed.
RF clock is used as a reference.

The new func/ons for new Event Timing
System are studied:Two‐layers of EVGs conﬁgura5onLong period of sequence: ~2 seconds
Switch input channels in every 20ms
Precision of output TTL /ming is comparedwith the SuperKEKB requirement,O(100)ps.
Long term stability is also studied.

Resultant jiker of 10‐15 ps is sa/sﬁed the SuperKEKB requirement.

10

AC 50Hz monitoring

Concrete design will
be decided soon.

11Injec5on 5ming must be synchronized with the revolu5on of injec5on ring.
‐ KEKB revolu5on/49/23 is used for SuperKEKB.
‐ Coincidence of 50Hz and above revolu5on is used for EVG trigger.
AC synchronized 50 Hz is used for coincidence.
‐ since Linac operates on the same phase of TEPCO’s commercial frequency.
‐ It is ﬂuctuated, 50.0±0.2 Hz. ⇒ Need monitoring and 5ming tuning.
AC synchronized 50HzKEKB revolu5on/49/23

TTL trigger to upper‐layer EVG
Also we need tomonitor.
We prepare two sets of AC 50Hz and KEKB revolu5on.
‐ onefor “coincidence ⇒ trigger of EVG”
‐ the otherfor “monitoring by TDC” ⇒ new TDC development, ongoing

12

Timing adjustment by lower‐layer EVG(Note it was implemented with dedicated delay modules, TD4V, at KEKB.)Coincidence of AC 50Hz
and KEKB revolu5on/49/23
MTS IOC

EventEVG

Timing adjustment is implemented with lower‐layer EVG.
Sequence of lower‐layer EVG must be updated in 50 Hz.

EVR

Timing adjustment should be implemented on EPICS.
Note, we use MRFIOC2 developed by BNL/LANL.
h#p://epics.sourceforge.net/mrﬁoc2/

EVGEVG

1st half ofLinac

2nd half of
Linac‐ However standard “waveform” record is used tomanage Event# to be delivered and its delay.
‐ It doesn’t accept input from “ao”, “longout”, and soon.
We need to develop special device support.

13

Reﬂec5ve memory for Bucket Selec5on
Bucket Selec5on System conﬁgures‐ another op5cal network‐ data transferring with reﬂec/ve memories.
Hardware‐ VMEVMI‐5565 is selected.
‐ Data transfer test (MTS‐KEKB nodes): 45.5MB/s.
Somware‐ Need device/driver supports for EPICS.
IOC Main Trigger Sta/onIOC KEKB control
Adjust injec5on 5ming for
Indicate injec5on
selec5ng RF‐bucket.
RF‐bucket

IOC D7
Measure charge ofindividual bunches

RM

BCM e+
BCM e–

Op/cal Cable

CPU

RM

CPU

RM

EVG
EVG
EVR
EVG
CPU

転送速度:
45.5MByte/s14Summary of upgrade works
Items

StatusOpera5on with new version of ﬁrmware and device driverDone

Tow‐layers of conﬁgura5on with diﬀerent periods ofsequence

Done

Opera5on with long period of sequence, ~2s(for upper‐layer EVG)

Done

Switch input channels for trigger in every 20ms
(for lower‐layer EVG)

Done

Timing adjustment in every 20ms for Bucket Selec5on(for lower‐layer EVG)

Need
somware development

Communica5on with reﬂec5ve memory for Bucket Selec5onNeedsomware development

AC 50Hz monitoring

Hardware development
ongoing

Feasibility studies
are performed
with test setup.

15

Constraints for Bucket Selec5on at LER
There are a few constraints for Bucket Selec5on at LER.
In the case “positron injec5on in >25Hz”,
a half of LER RF‐buckets cannot be selected for next injec/on pulse.

Only 31 buckets can be used if DR‐buckets have alreadyoccupied with the positrons for one pulse before.
‐ Note, this condi5on is for two pulse injec5on.

Only 13.5% (=31bucket/230bucket) of injec/onpakerns can be used for the next injec/on.

allowed buckets
100ns

DR

harmonic#:230

OccupiedRF-bucket

100ns

RF‐buckets already occupied and their ±100ns
region cannot be used for the next pulse.

16

Example of allowed RF‐buckets
If #0 and #49 of DR RF‐bucket havealready occupied, only #100‐#130 are
allowed for the next pulse.
Red color indicates allowed RF‐bucket.

102
70‐1003440‐705610‐40780‐109It makes the constraint for LER RF‐bucket.
Half of LER RF‐bucket cannot be injected.
Red color indicates allowed RF‐bucket.

100‐130200‐229

Only ﬁrst 250 of 5120 buckets are shown.

170‐200

140‐170

110‐140210‐229

DR RF‐bucket#

LER RF‐bucket#

Allowed RF‐buckets change every 5me and they can becontrolled by Event Timing System.
We can inject into the aiming RF‐bucket within a few pulse.
New Bucket Selec/on has capability for equalizing charges for individual bunches.

17Future upgrade for Bucket Selec5on
One of diﬃcul5es for Bucket Selec5on is diﬀerent RF frequency:‐ Linac:2856 MHz(10.385MHz × 275)
‐ MR, DR:
508.9 MHz
(10.385MHz × 49)⇒ RF phase shim is planned for “very near” future upgrade.
Phase shir at 2nd half of Linac and DR are considered.
‐ Both are commented in the KEKB review 2012.
‐ We discussed merits/costs/man‐powers/5me.
⇒ We decide the Linac as the ﬁrst priority and DR as the back‐up.
2nd half of Linac

DRRange of 5ming adjustment(from 0‐11.34ms)

0‐231µs

0‐493µs

Number of shir types49 types including original

230 types including originalWhen?

just before injec5on pulse

during dampingHow?

just switch phasechange phase graduallyNote, large phase shim is diﬃcult
within 20ms.

Upgrades in both Event Timing System and LLRF are needed.
We plan to use data buﬀer transferring on the Event Timing System network.
‐ indicate RF phase for next injec/on from Event Timing System‐ feasibility tests are ongoing.

18Summary
Upgrade of Event Timing System is ongoing for SuperKEKB.
‐ Positron injec5on needs special cares because of DR.
‐ Two‐layers of EVG conﬁgura5on is employed.
‐ Some developments for sorware and hardware are remained,
however I think, they are not hard tasks.
Bucket Selec/on System is integrated into the new Event Timing System.
‐ Delay is added on the lower‐layer EVGs.
‐ Complicated 5ming management for positrons can be realized.
Bucket Selec/on for SuperKEKB is discussed.
‐ Bucket Selec5on has capability to equalize charges of individual bunches
even though there are constraints because of DR.
‐ Arer ﬁnishing the ﬁrst conﬁgura5on and star5ng commissioning ofSuperKEKB, the upgrade is planned.

19Sorware
KEKB

SuperKEKB

EVG ﬁrmware

E4030005

EVR ﬁrmware

D5070005

EPICS device driver

mrﬁoc†

mrﬁoc2‡EPICS version

R3.14.9

R.3.14.12.1† developed by SLS/SLAC/LANL

hvp://epics.svn.sourceforge.net/viewvc/epics/applica5ons/trunk/mrfEventSystem/‡ developed by BNL/LANL
hvp://epics.sourceforge.net/mrﬁoc2/

20Constraints for Bucket Selec5on at LER
There are a few constraints for Bucket Selec5on at LER.
In the case “positron injec5on with >25Hz”,
a half of LER RF‐buckets cannot be selected for next injec5on pulse.
Injec5on 5ming should be adjusted in range of 0‐11.34ms.
However only 2ms width are allowed in terms of hardware.
‐ Note, injec5on must be carried out within 2ms 5ming
window which comes every 20ms.
Only 17.6% (=2ms/11.34ms) of injec/on pakerns can beused for every injec/on.
Positrons are injected from 230 of DR‐buckets.
However only 31 buckets can be used if DR‐buckets havealready occupied with the positrons for one pulse before.
‐ Note, this condi5on is for two pulse injec5on.
‐ This happens when we inject positrons in >25Hz.
Only 13.5% (=31bucket/230bucket) of injec/on pakerns
can be used for the next injec/on.

allowed buckets
100ns

DR

harmonic#:

230Occupied
RF-bucket

100ns

RF‐buckets already occupied
and their ±100ns region cannot
be used for the next pulse.

21

Conﬁgura5on at Damping Ring
114 MHzRF〜50 Hz

AC

Damping Ring

EVG(MRF)We choose the SINAP modules sothat following advantages areu5lized at Damping Ring.

EVR(MRF)OUTPUT1

EVO(SINAP)

EVE(SINAP)

RF〜509 MHz

EVO works as EVG (or EVR).

‐ Sequence RAM can be triggered by the upstream Event.
⇒ simplify the Event System conﬁgura/on‐ can be operated with diﬀerent frequency from that ofupstream‐EVG. ⇒ can be synchronized with RF clock of DR

EVE works as EVR.

OUTPUT2for BPMs

22Long term stability
Five days of con5nuous opera5on from Jun13 to Jun18 in 2013.
‐ Mean and jiver of 5ming is measured in every one minute.
‐ Room temperature is monitored at the same 5me.

Eﬀect of air condi5oning is seen.

There is correla5on with temperature.

There is no correla5on withtemperature.

Timing drim of 18ps/degree
is observed.

23

Jiker (ps)Test of three inputs
AC IN
IN0
IN1

delay at EVG (clock)24

Performance Test of Reﬂec5ve Memorytransfer rate:
45.5MByte/stransfer /me for 15MByte (seconds)

25

Injec5on 5ming
Injec5on 5ming must be synchronized with the RF‐bucket of ring to be
ﬁlled, otherwise a beam cannot be injected into the ring.
KEK Linac injects e+/e– beams into 4 rings in 50Hz.
“Injec/on in 50Hz” means ...

Injec5on is performed within 2ms 5ming window (500µs@KEKB) which comes
every 20ms.

Prac5cally, for this synchroniza5on,the (frequency divided) revolu/on signal of injec5on ring is used.
‐ revolu5on/49@KEKB‐ revolu5on/49/23@SuperKEKB

26

Test for New Systemdelivered by one trigger

EVR generates
NIM/TTL

EVR interrupts CPU.
Setup parameters for nextpulse.

27

Test for New System

Failure rate (%)

x‐axis0/2255980 = 0 %0/1987743 = 0 %Time (ms)28

Precision of output TTL

Sequence Length（clock, 8.8ns）

29RF周波数による制限
LinacとKEKBでは使用しているRF周波数が異なる
Linac:
2856MHz(10.39MHz × 275)
KEKB:
508.9MHz(10.39MHz × 49)
そして入射を実行できるのは両方が「ビームを乗せられる位相」に揃うとき

Linac
2856MHz

・・・・・・

KEKB
508.9MHz

時間（ns）

本当は1.96ns毎（508.9MHz）にバンチが入射点を通過だけど入射できるのは96.3ns毎（10.39MHz, 49バンチクロッシング毎）

30

RF phase shir at 2nd half of Linac
Linac後半（DR‐MR間）のRF位相を入射MRバケットに合わせて変調する。
Normal + 48個の変調位相を50Hzで切り替える

2856MHz

Linac後半位相

例えば、DR#1からMR#1への入射を考える
通常入射では⇒ ‘delay=3.5ms’

2020.4度（220.4度）
変調

RF位相を2020.4度（MRで360度分）変調⇒ ‘delay=1.96ns’
同様にDR#2からMR#2も ‘delay=3.92ns’
DRバケット#0, #49が埋まっている（#100‐#130使用可）のときMRバケット#0に入射できるのは以下の4つ
DR#

変調あり

変調なし

100

170.6µs

10.35ms

110210.7µs

3.451ms

12020.1µs

7.889ms

13060.2µs

986µs

1.96ns毎に入射機会が得られより短期間で各DRバケットに入射機会が訪れる

4040.7度（80.7度）
変調

508.9MHzDR/MR位相時間（ns）

31

Eventスケジュール

写真

例えばKEKBでは#31: MR電子準備#32: MR電子入射#41: MR陽電子準備#42: MR陽電子入射#61:PF#62:PF#71:PF‐AR#72:PF‐AR