ipbpm issues (limitation of resolution) siwon jang (knu)
TRANSCRIPT
IPBPM issues (Limitation of resolution)
Siwon Jang(KNU)
Contents
• The status of IPBPM resolution measure-ments– IPBPM calibration measurements with Y-port sig-
nals– IPBPM resolution measurements with Y-port sig-
nals– The limitation of resolution with Y-port signals
• The IPBPM measurements issues– Static signal and BPF– Ref. cavity BPM resonant frequency matching– IQ phase tuning– Honda electronics gain
3
Calibration run of IPBPM• We performed calibration run under the 0dB to 30dB.
– The used optics was 100 x 1000 beta optics, which optics has 1um level jitter for IPA, IPB, IPC.
– The QDOFF was set to 129.047A of IP waist.– The used method was integration method from #54 to #80 sample numbers.– Also I’ and Q’ does not normalized by Ref_Y signal to compare with Honda san’s pa-
per method.
• The Calibration factor was calculated by (All the signal was inte-grated),
I’ = ( I*CosX + Q*SinX ) [counts], Q’ = ( Q*CosX - I*SinX ) [counts]
Calibration factor = ( Δ I’ [coounts] )/( Δ Mover position [um])
• All the I and Q signal were taken mean subtract calculation.
Calibration run of IPBPM
5
IPBPM A calibration• The integrated calibration factor from 30dB to 0dB shows good ratio to
around 3.162 times for every 10B attenuation case. The fitting line was ex-trapolated from 30dB calibration factor.
6
IPBPMs calibration• The integrated calibration factor from 30dB to 0dB shows good ra-
tio to around 3.162 times for every 10B attenuation case.
7
Resolution calculation: 0dB
• We performed resolution run under the 0dB– The used optics was 100 x 1000 beta optics, which optics has 1um level jitter for IPA,
IPB, IPC.– The QDOFF was set to 129.047A of IP waist.– The used method was integration method from #54 to #80 sample numbers.– Also I’ and Q’ does not normalized by Ref_Y signal to compare with Honda san’s paper
method.
• The Calibration factor was calculated by (All the signal was inte-grated),
I’ = ( I*CosX + Q*SinX ) [counts], Q’ = ( Q*CosX - I*SinX ) [counts]
Calibration factor = ( Δ I’ [coounts] )/( Δ Mover position [um])
• All the I and Q signal were taken mean subtract calculation.
• Predicted position was calculated as follow equation,– Predicted position of IPA-YI’ = a1*IPB-YI’+ a2*IPB-YQ’+a3*IPC-YI’+ a4*IPC-YQ’+
a5*Ref-Y– Residual of IPA-YI’ = Measured IPA-YI’ – Predicted IPA-YI’
20dB calibration 1220 owl shift
0dB calibration 1220 owl shift
10
IPBPM resolution Study
The calibration factor of IPA with 0dB was 4606.66 counts/um.The ADC counts was multiplied 2.5 times for 5V range.
11
IPBPM-A resolutionRMS of residual for IPA resolution calculation (RMS = 558.029 counts) :
RMS/(Calibration factor)= 1558.029counts/(4606.66 counts/um)= 121.135nmGeometrical factor x RMS/cal = 66.1048nmMeasured chage/norm charge x Geo X RMS/cal = 30.081nm
12
IPBPM-B resolutionRMS of residual for IPA resolution calculation (RMS = 237.626-counts) :
RMS/(Calibration factor)= 237.626counts/(4006.97 counts/um)= 59.3032nmGeometrical factor x RMS/cal = 47.3732nmMeasured chage/norm charge x Geo X RMS/cal = 21.5572nm
13
IPBPM-C resolutionRMS of residual for IPC resolution calculation (RMS = 776.998-counts) :
RMS/(Calibration factor)= 776.998counts/(4607.57 counts/um)= 191.387nmGeometrical factor x RMS/cal = 48.4439nmMeasured chage/norm charge x Geo X RMS/cal = 22.0444nm
14
Beam orbit re-construc-tion
The data set was taken under the 0dB attenuation.
[mm]
The comparison with old IPBPM
• The High-Q IPBPM was achieved 8.72 nm with 0.6 x 1.6nC, which cor-responds to 5.94nm with nominal beam charge. Also the measured residual counts was 22.02 with full BPM output ports.
• If only used Y-port data then the residual counts changed to 69.08 counts, which corresponds to 27.37nm with 0.6 x 1.6nC. Also this value corresponds to 16.43nm with nominal beam charge.
• Therefore, the Low-Q IP-BPM also have a possibility that the resolu-tion can be reduced with full chan-nel calculation.
• The current BPM resolution has limit around 20nm with Y-port so that weexpect if we used full channel sig-nals of IPBPM then we can get more good position resolution with IPBPM.
The IPBPM measurements is-sues
• Static signal and BPF
Static signal with 0dB Elimination of static signalBy using BPF with 0dB
Delay
The IPBPM measurements is-sues
• Ref. cavity BPM resonant frequency matching
Time-dependence of θIQ
The IPBPM measurements is-sues
• Ref. cavity BPM resonant frequency matching
Tuner range: 3~10.5mm, Fre-quency range: 6.386GHz to 6.441GHz (f0: 6.426GHz)We will make table the reso-nantFrequency due to tuner depth.
The IPBPM measurements is-sues
• IQ phase tuning
Figure by N. Blaskovic
IPA(Y) IPA(Y)
Before the phase matchingIQ angle has no time depen-dency
After the phase matchingIQ angle has time depen-dency
The IPBPM measurements is-sues
• Honda electronics gain
Thank you for your attention!