Attached is a spreadsheet summarizing all the run information from the experiment.

Attached. Book 13 is split into 4 sections as otherwise the file is too big for the elog to accept.

2um x 8 mm Ni windows leaked tested on TUDA gas cell. With window placed on the outside of the cell, cell was evacuated and pressure monitored with time, i.e. 1atm differential air pressure. Comparison to leak rate with blank flange also do.

Tests were performed in order: Ni, 30 minuets pumping, Ni again, blank, Ni third time.

Plots are the same data, different scales.

attached

note. s2 position in fig. 1 is wrong, should be 360mm.

27/06/11 - final version of safety report added (produced just before the experiment began).

Attached plot shows rate of pressure increase in ~2l volume upstream of TUDA with Ni window #2 installed on reentrant flange. Comparison between

a)pumping out TUDA and 2l volume, and

b) filling TUDA with ~340mbar of He and pumping out 2l volume.

In both cases, 2l volume isolated from pumps at start.

Gradients are comparible, hence no detectable He leak through window.

Will repeat with other windows and blank flange tomorrow.

Alignments checks revealed that downstream end of TUDA was ~1mm off (can't remember which way).

Re-entrant flange (window end) found to be ~5mm too low and ~2mm to the left. Checked upstream end of chamber and was ok.

Removed bellows etc. and re-entrant flange, replaced with re-entrant flange bolts only figure tight. Tighten bolts from inside chamber whilst checking alignment, adjusting as appropriate.

Managed to get to ~0.5mm to the right and ~0.25mm too low.

This is acceptable so closed chamber and checked vacuum down to ~150mTorr.

York W detector 2635-19

1037um

still running at 3.98 MeV/u

19:08

S2-1 had tripped off due to leakge current going above 8uA

Camera watching leakages had also frozen so didn't realize until we checked downstairs

asked to lower beam intensity down to 55epA (was 120epA) @ run119

23:22

asked to set beam intensity to 100epA

upper limit of leakage set to 20uA

S2-1 leakage current ~9.93uA

Sorted Runs:

run120

run121 still running

For run 123:

Beam outage for ~15 min but not stopping run.

FC0 = 120pA when we got beam back.

We'll let the run go 15 min longer.

Run 125 stopped early because of strange rate values on scalar 1.

Sorted Runs:

Finished 121

122

123

124

Sarah informed me that Jamie was performing the sorting and saving of spectra differently and didn't know what exactly to do so I will not be performing any sorting.

01:40 Run 144 Stopped

01:45 Run 145 Started

03:43 Run 145 Stopped

Stripper foil changed, still seeing fluctuations so the problem could be in the SC-LINAC

03:57 Run 146 Started

Rate durring run 146 has been a little low, will ask for more at the run change.

05:50 Run 146 Stopped

FC0 averaged 65pA for run146.  Got it back up to 100pA for the next run.

05:54 Run 147 Started

06:15 No beam, lost a SC cavity.  Run 147 stopped

06:42 Beam back.  Run 148 started and stopped due to low scaler 1 reading

06:43 Run 149 Started

07:10 Rate dropped back down to ~4200, FC0 = 60pA.  Stopped run 149, saved and zeroed the histograms

FC0 back up to 100pA

07:13 Run 150 Started

Handover from last shift was...

1. Running at 4.11 MeV/u at about 15enA (5+)

2. Would like to take more beam but already at situation where deadtime about 50%.  They have been raising thresholds on the inner strips of S2-1 to try and cure that, but it doesn't appear to have helped.

3. There is a sort of the past runs ongoing to use the counts in spectrum 4200 (coincidences) to estimate when there is enough data at this energy to move to the next.

Analysis:

Firstly, the locus being looked at in the S2-1 vs S2-2 to make this judgement cant be right.  There are already thousands of counts in this in a replay of a one hour run  Jamie's estimates in the run proposal were for 1,000 in 12 hours at 10**8/s.  We are currently at 20% of that beam intensity and the deadlime is about 50%, so should be seeing 10 counts in one hour.  The data must be somewhere else in the plot.  My guess is that the intense locus is elastic/inelastic scattering coincidences.  If this is the case then it maybe we have an issue in that these may be what is dominating the rate and it will not be possible to get rid of them from the trigger.

Looking at the S2-1 energy spectra, it looks like the raised threshold is cutting into potential data (maybe Alex who knows from the MC what energy the data extends down to should look at this and check).  The high trigger ratemust be from another channel.

Actions for this shift

1. With two people on shift and a requirement that we need two down in the area at all times, I don't think chasing thresholds is viable.  This will have to be left to the day shift.

2. Should continue the sorts so that we have the spectra available to make rate estimates once we know what we are looking for.

3. Should look at the sort code to see what calibrations are being used and so determine where on the coincidence spectrum the data should lie.

Summary at start of run

Read through the runbook and end of run summar and the situation appears to be:

1. The check of the tune showed it was OK, although a bit of beam (or halo) clipping 4mm collimator

2. There are some changes to the gas filling scheme - Jamie should be present for the next one.

3. Evidence that the gas pressure is dropping slowly - need to watch this

4. Trigger is Coinc.OR.SS_2.OR.PD.  Rate at this is 200/s at 4epA (50/50 Coinc and S2_2)

5. Suggestion we could increase the beam a factor of two to get back to the same coinc rate.

Analysis.  Looking at the rates I see:

Running at 66 pnA and see about 4,000/s triggers and 3,200/s accepts. Scaler 9 over 40,000/s.

Looking back in run book the max trigger accept rate we see is about 3,800/s.  Could double beam and gain only

modest increase on accepted rate, but at cost of faster damage of detector.  Suggest we run

like this for a bit and make sure all is well.

Took a look through the spectra.  All ADCs OK, but no TDC signals.  Checked past saved runs.  There up

to run 98.  The next saved on disc is run 104 and they aren't there.  Nor in any saved runs after this.

Looked at electronics and reason clear as the module providing the TDC trigger (lower section of a

429 unit) has no input.  Eventually determined that it would make sense if this unit was operating

in 2 x 8 mode rather than what it is currently set on (4x4).  Switched this over and now working OK.

Assume this was changed inadvertently during all the work on the chamber yesterday.

0300.  Running again and all ADC and TDC spectra make sense.  Off for a cup of tea.

Running status

Everything seems to be running OK.  ADC and TDC spectra look OK.  Chamber pressure has stabalised.  Detector leakages stabalised

Beam now up to 60pnA with trigger rate about 4,000/s and accepts about 3,000/s

Have spent some time looking at sorted spectra and put notes in the runbook, along with a copy of an email from Tom with some suggestions.  Need someone who can change the sort programme. The key is probably in getting the plot of Tdiff vs Esum calibrated [Tdiff is time difference between S2-1 and S2-2 signals and Esum is the sum of their energies].  The problem is that the TDC signals have not yet been lined up.  We also need to understand the features we see in the E vs t plots, including the puzzeling feature that one of the loci has its "blob" of events at a different energy than the others.

My feeling is that we should continue to run ast this energy, while continuing to refine the sort to try and confirm we can select out the (a,p) events of interest.

Worth thinking as to whether we should take more beam (it is available.

This is reachable and change-able via outside Internet

 Wednesday morning:

4 new windows were tested last night. 2 very good.

Now venting to install and test Faraday cup, install and test camera.

Remaining to do list:

Before beam - 

 beamline on SEBT back in and pumping upstream section

(measure C and C/Au target thicknesses if time)

replace 4mm collimator on plate with 10 mm for tuning

confirm PD0 problem just connector

install detector shields and pump down

walk round TUDA and check no grounding compromises

Before running -

runplan

procedures tick list for H2

runlog and detector current list

exclusion zone and Al plate before running H2

No major problems presented, A pluser walk was performed at the begining of the shift run161 S2-1 front, run162 S2-2 front, run163 S2-1 back and run165 S2-2 back.

Runs 166, 168, 169 are void due to bad scaler reading

Two times the control room reported the dipole magnet tripped but beam was recovered within few minutes. FC0 readings range 150-120epA

S2-1 L. current 17.60uA @ 16:00 and 18.85uA @ 23:10

 In attachment are the peak position in the photodiodes (with high gain setting) for the target thickness measurements.