(1.393*^-8 + 3.18*^-13 + 4.707*^-8)/4.707*^-8 = 1.29595

The frequency of the clock used as reference in scaler channel 13 has been measured precisely.
In contrast to what was expected (1.5MHz precisely), it is: 

f_ref =  1.5625(5) MHz

slit	Ratio	error
-1	18.64	0.4
-2	18.18	0.38
-3	20.85	0.5
-4	18.15	0.34
-5	17.44	0.31
-6	17.38	0.32
-7	17.82	0.32
-8	16.41	0.27
-9	18.51	0.37

decay line of 205Tl beam with Ar gas jet target on and S6 slit at -8mm
Ar gas density~1e12 atoms/cm2

Ionization cross section = 1320 barn.
Capture cross section = 557+137+44.5=735.5.
sigma_Ion/sigma_cap=1.79

This is a collection of energy spectra of the CsISiPhos detectors from run0251 with primary beam.

There is no good spectra for n-side of Si-pad 1!

Attached are plots for Si-pad 2 with hits from ionization of 206Pb81+ at the target.
The plots are representative for all Si-pads, the pattern is always the same!

y-axis: E n-side
x-axis: E p-side strip
condition: E_gate on peak in CsI

While strips 1, 2 and 7 look fine, strips 3 and 6 show already signs of degradation. 
For strips 4 and 5, it is clearly visible that something is wrong.
Those are the central strips, which probably see the most rate.

The same dataset was analyzed here: https://elog.gsi.de/esr/E121/62

This might be a hint to a radiation damage or to the fact that we operate at too low bias voltage (32 Volt).
Maybe it recovers if we increase bias to 60 Volt.

I analyzed the first measurement with 206Pb81+ beam, run 250-267. 

1.connect USB harddisk  to computer lxg1254 and  copy data to sever.

sync -rtmv --progress --checkSUD  /media/sdgl/data/ litv-exp@sbk0l9:/lustre/ap/litv-exp/2020-
04-14 e121_rchen/NTCAP/hd1

2020.05.02 08:06 copied 11.88 TB to server. 1.8TB rest on hard disk.

  root [1] .L e121_analysis.C++
  root [2] run()

#include "e121_raw.h"

#include "e121_mapped.h"

store 206Pb81+ beam inside ESR and measure its halflife. 
The HV of detector is off.
Start DAQ to record the ESR current in lmd file.
Nik is optimizing the gas jet target. So this file is still test run.

Sergey and Yuri are tuning Tl beam. The particle number in ers is about 1e4. I(SIS)=5e8
run stop: after few minutes (garbage data)

move the detector 1cm 
outside.from 60mm to 
70mm.
left direction is 
outside. right direction 
is 
inside(close to beam).
the spot is moving from 
left to right.

s6 positon at 50mm.

2020.4.8  12:00Started copying 
data。
2020.4.9    11:52 Copied 6.3TB 
data. The copy speed is 65-67MB/s.
2020.4.15 Bring the two USB hard disk to my office and connect them  to lxg1298 computer.
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