4th bepcii imac meeting - 1 - april 26 - 28, 2006 status of bepcii storage rings ma li april 26,...

4th BEPCII IMAC Meeting - 1 - April 26 - 28, 2006

Status of BEPCII Storage Rings

Ma Li

April 26, 2006


SRF SystemMagnet SystemPower SuppliesVacuum SystemControl System

Beam InstrumentationInteraction Region

Pre-assembly and InstallationScheduleSummary


SRF System 2 superconducting RF cavities

#2 cavity assembly has been completed in the last month and moved into the test station. Input coupler aging and horizontal high-power test of the cavity will be performed soon.

#1 cavity assembly is carrying on at present. The crack on the ferrite surface of one HOM damper SBP-2 has

been found in December 2005. At least 6-7 months is needed to fabricate a new damper. To keep the cavity assembly on schedule, we borrowed a damper from KEK.

2 klystrons and power supplies Klystrons and power supplies have been installed and passed the

acceptance tests in December 2004 and January 2006, respectively. Low-level RF control system Assembly is in progress. Cryogenic system Cryogenic system for SRF with the dummy load has been tested.

Control accuracy of pressure, LHe level satisfies the requirement.


bakeout HOM damper clean room

HOM damper


#2 cavity in test station

LHe lines

Waveguide and doorknob


installation and test the second klystron and power supply


wiring and commissioning of LLRF


test of cryogenic system for SRF with dummy load

valve box

2000L control dewar

pressure curve

dummy load


RF SystemMagnet SystemPower SuppliesVacuum SystemControl System




Magnet System 95% of the ring magnets has been fabricated and field measured

48 dipoles (67B) 44 old dipoles (70B), field measurement only 88 quads (105Q) 28 old quads (110Q), coil modification 6 old quads (160Q), field measurement only 72 sextupoles (130S) 48 vertical dipole correctors 4 injection kickers 2 wigglers, one is repaired in-vacuum PM wiggler

Following magnets are still in fabrication 1 quad, for SR mode only 8 skew quads 6 special dipole correctors


injection kicker magnets and power supplies in test

discharge circuit controller

kicker

HV PS


new PM wiggler 1W2


4W2 in-vacuum PM wiggler We had a problem of demagnetization for the in-vacuum PM wiggler

. The field is reduced by 30% after nearly 3-year operation in the BEPC storage ring. Study shows that the reason might be the heating caused by HOM and SR. There was no water cooling applied.

The old wiggler has been repaired and upgraded. New NdFeB blocks with demagnetization temperature of 180ºC is

used. Water cooling will be used during the operation and the experime

nt of the cooling effect has been performed. A movable beam chamber has been added to reduce the impedan

ce for the colliding mode. The upgraded 4W2 has been installed into the ring tunnel at present.


demagnetized in-vacuum PM wiggler 4W2

burn here


repaired in-vacuum PM wiggler 4W2

movable chamber


Power Supply SystemPower supply Qty Amps Volts Status

OB 2 1050 170 installed

IB 2 950 310

105Q 128 200 65 installed

130S 36 200 55 installed

BT 60 25 20 delivered

BV, BH 84 40 26

ISPB 1 1450 100 3 IR special magnet PS

Q1a 1 1750 116 in fabrication and to be delivered in June

Q1b 1 1400 176

Q2, Q3 8 500 40 installed

110Q 6 570 16

AS1 2 1380 14 16 superconducting magnet PS

AS2, AS3, SVCB, SKQ 10 65 12 installed and commissioning underway

SCQ, SCB 4 600 8


assembly and commissioning superconducting magnet PS

install B, Q, S-magnet power supplies of rings


Vacuum System 80 arc chambers all delivered 120 straight section chambers 48 (about 40%) is complete. Expect all will be delivered in May. TiN coating for e+ ring chambers Coating for arc chambers has been completed. Coating for straight section chambers is underway. Measurement results show that maximum SEY are 1.6-1.9. 175 discrete photon absorbers 129 (73.7%) complete 180 RF shielded bellows all delivered vacuum valves, pumping and monitoring devices all delivered


Arc chamber distortion We found an arc chamber problem in October of last year, when ¾ o

f the chambers were completed and 24 of 80 chambers were pre-assembled.

The baking temperature is required below 150ºC. The vendor overheated during the bakeout, causing the chambers to be depressed by as much as over 10 mm. This closes the 15 mm high anti-chamber gap and blocks the SR.

The simulation has been made and the height of anti-chamber gap of minimum 10 mm is decided. We measured all 80 arc chambers and found 20 have to be fixed.

Several methods were tested to recover the chamber distortion and two of them have been used finally. Fill the gas N2 into the chamber to 3.8 atm to pump back the cha

mber dimension. (for small distortion) Pull outward and distort the chamber locally. (for large distortio

n)


BEPC chamber

depressed BEPCII chamber

distortion here


filling compressed gas N2

gas N2 input


pulling outward jack tooling block jack


max. distortions before and after corrections

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1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79

真空盒序号

最大

变形

量(mm)

矫形前矫形后

From here bakeout temp. was asked to be lower than

120ºC.

(date of delivery)


Control System Device control Development of hardware and software of control system for PS, vacu

um, SRF, cryogenics, etc has been completed. Main tasks of the next step are installation and commissioning.

Timing system Event timing system has been setup and provides trigger signals to the

linac. Server computer and network Installed Accelerator high-level applications Optics, COD correction, iBump, transport line, etc. nearly complete Interlock and machine protection system in progress


installation and commissioning for PS control system


event timing system


commissioning cryogenic control system


Beam Instrumentation System 134 beam position monitors all arc chamber BPM complete 2 bunch current monitors hardware delivered, software development in progress 2 tune measurement system components ordered 150 beam loss monitors processing electronics in fabrication. 2 DC current monitors ready for installation 2 synchrotron light monitors ready for installation 2 transverse bunch-by-bunch feedback prototype electronics tested in BEPC one of the two 4-strip kickers delivered and tested


SLM BPM

button


transverse bunch-by-bunch feedback system

feedback off feedback on

sideband

prototype


IR System 2 superconducting IR magnets delivered and installed 2 septum bending magnets (ISPB) delivered and field measured 4 two-aperture quads (Q1) delivered and field measured 8 slim quads (Q2, Q3) in fabrication 12 dipole correctors in fabrication IR vacuum chambers in fabrication, expect to be complete in May


install superconducting IR magnets SC wires


Pre-assembly and Installation The pre-assembly and pre-alignment on magnet/chamber rafts

restarted at the beginning of last December after one-month interruption caused by the arc chamber problem.

Now 50 (59.5%) rafts have been completed. All 84 rafts will be completed in the early July according to the updated schedule.

The installation of the first magnet raft has started on March 2. 29 (34.5%) have been located since then.

A traveler (inspection sheet) is designed for QA. This traveler includes pertinent pre-assembly records and inspection results.

The procedure for the combined commissioning of magnet, PS and control systems has been established. The step-by-step inspection will be performed before the commissioning.


50 rafts pre-assembled 29 rafts installed


traveler of pre-assembly

signatures


procedure for inspection and combined commissioning of magnet, PS and control systems


dismantling of old ring components


installation


install RF shielded bellows


Backup scheme without SCQ A backup scheme for the IR lattice configuration will be adopted.

Two normal conducting dipoles (70B) are used to replace the two superconducting IR magnets. With this backup scheme, the outer ring, the electron ring and positron ring can be commissioned, respectively.

The main purpose of the backup scheme is to save the time of about 3 months for the SCQ field measurement with detector solenoid and the field mapping of the detector solenoid itself.


beam orbit in IR for the backup scheme

70B dipole 70B dipole


IR layout of the backup scheme

70B dipole 70B dipole


Schedule of IR

-2006/05/03 install SCQ and valve-box and wiring2006/05/04-2006/06/10 38 preparation & check for SCQ cryogenic system2006/06/11-2006/07/08 28 commissioning SCQ cryogenic system2006/07/09-2006/08/27 50 SCQ field measurement in IR without detector2006/08/28-2006/09/07 11 move out SCQ from IR2006/09/08-2006/09/21 14 install IR components (backup scheme)2006/09/22-2006/10/09 18 commissioning vacuum, PS etc. of IR2006/10/10- start commissioning of the rings

2006/09/08-2006/09/18 11 install SCQ at BESIII pre-assembly location2006/09/19-2006/10/22 34 commissioning cryogenic system2006/10/23-2007/01/15 84 field measurements for SCQ and detector soli.


Beam Commissioning Schedule

2006/10/10-2006/11/08 30 commissioning outer ring for SR mode

2006/11/09-2006/12/28 50 commissioning beam lines and SR operation

2006/12/29-2007/01/25 28 commissioning e ring


2007/02/23-2007/03/31 37 move SCQ into the IR



2007/05/11-2007/06/09 30 commissioning for collision mode

2007/06/10-2007/08/23 75 commissioning for colli. mode with large current

2007/08/24-2007/09/18 26 move BESIII detector into the IR

2007/09/19-2007/10/14 27 commissioning for collision mode

2007/10/15- HEP operation with detector

Jiuqing will give detailed descriptions for each step of commissioning.


Summary

Many problems were encountered and resolved. Progress has been made since the last IMAC meeting.

The BEPC old ring has been removed in the last July. Installation of magnet/chamber rafts started on March 2 of this year.

Comparing with the schedule presented on the last IMAC meeting, the updated schedule delayed by several months, due to arc chamber problem, delay of straight section chambers, delay of superconducting equipments and cryogenic system.

Installation, horizontal test, field measurement of superconducting IR magnets is one of the critical paths of the project. A backup scheme of using two normal conducting dipoles instead of SC IR magnets will be adopted, in order to start the commissioning of the BEPCII rings in the last quarter of this year.


Thank you for attentions !

4th bepcii imac meeting - 1 - april 26 - 28, 2006 status of bepcii storage rings ma li april 26,...

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