All ran smoothly.

As a test, ran for a short period at 1200 midday to run without S2-2 in the trigger. Finished that at 1339.

After discussion with Alison, Alex, Brian, Chris - we decided to change energy to 3.98 MeV/u. This started at 1340.

Pumped out H2, Marco steered with low intensity beam. He optimized on our PD2 with the 3mm collimator, then he observed the spot on the scintillator. He believed (as do I) that it looked as good as it did after the high-intensity tune yesterday. Beam spot blown up a bit, as before, but very well centred. picture from iphone below.

Did a run without gas, then filled, then got going on H2. H2 run started 1730. Thus, 4 hours for beam change and low-intensity tune.

Did analysis of rates/triggers with and without gas - all with 100 epA

                     WITHOUT GAS        WITH GAS

S2-2 all           3000                        3800

PD                   1500                        1900

Coincidence  10                            1800 

S2-1 all           13000                     57000

The trigger (7000 ish) is a sum of the first three of course. Interesting that all the coincidences are gas-"related" - which is good I think. It confirms to me that we should consider, at some point, running on only coincidences in the trigger to cut down the dead time (currently 60% live, 40% dead)

that's it. Jamie checking the spectra, if nothing else in this e-log then they are ok.

Sort started on new data, will run it overnight and compare in the morning with the old sort.

Mike

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.

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.

Buncher problem was resolved around 22:00 (driver module needed to be replaced).
Checked current on FC0 and trigger rate, around 4000 presented. We then started a run, only got 20 acquired,
stoped and restarted a run, then all relevant numbers seemed normal.
The pressure inside TUDA is slowly creeping down (~0.3 torr/h), maybe a small leak in the window. It's not the
hall cooling down, the gas temperature actually rose in the meantime.

 Update: 

W decided at 8.00 to stop, check the tune, retune and get back going. This has nearly, finished but it is a very long process indeed - note for future - this takes AT LEAST 12 hours, if one is systematic about it.

We tested the tune as it was - it was OK, (90% transmission or so acdording to a straight ratio of the cups) but there are a fair bit on the 4mm collimator. 

Marco then tuned, and improved it with a high intensity tune, reduced the rate on the collimator by at least a factor of 5 - maybe more. Good position on scintillator - see photo below.

We have since pumped out and run several tests with the window in, but no gas: (1) 10mm collimator on first target ladder, nothing on second - transmission was about the same, measured the same way. Rate similar to same test we did a couple of days ago. (2) 5mm collimator and blank second target - result about the same. (3) 5mm collimator and scintillator in - photo below. Beam spot blew up a bit compared with no gas. See below. (4) 5mm collimator and PD2 (5) 5mm collimator and blank. Ran this to disk. and (6) CH2 target. This made no sense and we got a lot of horrible ate of this so we stopped it.

We saw noise in S2-2 when we had no gas. It was bad - 1200Hz with no beam - all from S2-2. When we put gas in, it all went away! We suspect that it was a gauge that we disconnected, perhaps.

Waiting for beam, as buncher has now tripped.

Note that full cycle (pump, flush, vent, tune, flush, pump H2) - with all the tests as you go along, took 12 hours!

The pictures below are tunes without and with the window. From Mikes iphone. !

 We have been running smoothly all night. Only problem is that the DAQ occasionally does not start properly after a stop-go. The dead-time goes to nearly 100%. This happened twice in the night,. and a second stop-go did the trick. Needs looking at.

We are going to stop now and (a) check the tune properly and (b) retune if necessary and then carry on the same energy. There is not really evidence in the data of the structure we are looking for, so we need to carry on at this energy for a while. This process will take 6 hours or so

MAB

1.TDCs. We have been sorting offline, and we have now established that between run 66 and run 79, the TDC mode
was incorrectly set (not in common stop mode) after a DAQ crash causing broad loci in the E vs T spectra and
times of the wrong sign. This was corrected from Run 81 onwards.

TDC channel 0 (reference channel) should have been recorded in the EbyE data - common stop TDC values
can therefore be calculated offline by switching the egid2logical logical variable csm from TRUE to FALSE.
  
2. The offline sort is behaving very badly and many of the sorts run since yesterday to now are wrong. Make sure
you (a) sort on a different machine than the DAQ and (b) make sure that the sort is killed each time you start a
new sort and (c) make sure that it is sorting the righrt run number.

Amen

Things have been running smoothly from 4 pm to midnight.

Reading in FC0 = 120-130 epA

Total trigger (accepted trigger) = 7500 (4000) Hz

Gas temperature has dropped from 30 to 22 deg C (due to evening cooling of experimental hall?). As a consequence, pressure has dropped by 0.2% (current value 249.8 torr).

Runs during this shift: 87, 88, 89, 90, and 91 (still running).

Runs 87-90 have been analyzed with sorting code.

Good night

 OK - summary of events during this shift.

1.TDCs. We have been sorting offline, and we have now established that between run 66 and run 79, the TDC mode was incorrectly set (not in common stop mode) after a DAQ crash causing broad loci in the E vs T spectra and times of the wrong sign. This was corrected from Run 81 onwards. 

2. The offline sort is behaving very badly and many of the sorts run since yesterday to now are wrong. Make sure you (a) sort on a different machine than the DAQ and (b) make sure that the sort is killed each time you start a new sort and (c) make sure that it is sorting the righrt run number.

3.  We have changed the trigger to a coincidence (S2-1 plus S2-2) OR S2-2 on its own OR PD.

4. We have increased the beam rate to about 120 epA and we stay on this. Trigger rate should be about 7K with 4K live time.

5. We will not change energy until early morning tomorrow, at the earliest. we will make a decision during the next two shifts based on what we see in the sort.

Mike

Ran all night OK, currently 14epA, H2 stable, DAQ stable

ISSUES:

1. Analysis of S4200 in offline sort lead to conclusion that specttrum is dominated by protons, 8MeV punchthrough visible??.Not many events at high energies, where Alex MC predicts them to be.

2.Noticed that 3 channels in particular in S2-2 have very high rates. All in same bank - can we raise thresholds?  Strips 34,36,46 in S2-2, we think (from mapping in sort code)

3.  The loci in the E vs T spectrum are (a) still aparrently upside down from what expected and (b) very wide in time. There is also a suspiciously sharp edge to the timing peak. Look at eny E vs T loci in the sort

4.Been sorting over night - nearly caught up.

We looked a run (54) from the first H2 run at 4.4 MeV/u and compared with the current data. The The S4200 spectrum and the E vs T loci look exactly the same.

Plan for shift was to increase trigger thresholds on S2-1 and S2-2 to cut out the low energy "stuff" which is dominating our trigger rate, and preventing us from increasing the beam current. S2-1 thresholds were at 10mV and S2-2 at 25 and 30mV.

Increased all S2-2 thresholds to 30mV and took runs with S2-1  at 11, 15, 20 and 40mV. Trigger rates seem unaffected. Low energy peak in S2-1 spectra are unaffected, however the bump at chn. ~380 was shifted up as threshold increased.

Looking at energy-energy spectra from sorted data, see lots of events at very low energy (y axis), across all channels (x-axis).

Concluded that the low energy peak is real coincidence, so can't be removed by increasing trigger threshold (as it is in coincidence with stuff in S2-2), and the "bump" is singles, so is being cut out as thresholds are increased.

Not clear whether the low energy peak is reactions, or something else, but the result is we can't increase the thresholds to cut the rate and allow the beam current to increase.

Following discussions with Brian, the interpretation of this may not be correct.

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.

 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

I've analysed data from runs 4 to 12, which were the alpha irradiations of PD1 and PD3 through the foils.
Time, 'target', which PD is being irradiated.

21:02 Ch2A 1
21:30 Ch2B 1
21:49 Ch2C 1
22:09 Ch2D 1
22:30 AuC 1
23:16 2mm 1
23:35 Au         3
24:23 4mm 3

Data are being sorted with sort.f, with the new variables file which has offsets and gains. 
The offsets should be fine, but the gains are based on data taken with the PDs in their
low-gain 'run' configuration. For these data, to be able to resolve energy loss at the scale of 10's keV, 
we needed higher dispersion, so the gains were increased. Hence the gains in the variables file 
cannot be used. We do a new energy calibration here.


Peakfind has been used to find the centroids of all relevant peaks. 
Using 2mm hole data (no energy loss except for deadlayer) I find the calibration of PD1 to be 4.74379 keV/channel. 
Likewise, using 4mm hole data for PD3 I find PD3's energy calibration to be 4.78963 keV/channel.


Energy losses for the three alpha peaks (5155, 5485, 5805 keV) are then:

Foil ch2-A: 

1077.0 keV
1020.4 keV
972.9 keV


Foil ch2-B

1121.6 keV
1060.8 keV
1010.9 keV


Foil ch2-C

1059.6 keV
1005.1 keV
952.2 keV


Foil ch2-D

1162.3 keV
1101.2 keV
1072.6   keV


Foil thin ch2+flash gold

12.3 keV
8.5 keV
10.3 keV


Foil: Thick gold

50.7 keV
50.4 keV
52.4 keV

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

The thick carbon target, to be used for background runs for the thick CH2 measurement was supplied by Marek.

He measured it to be 120um thick (with a micrometer), and says it's low density carbon (1.03g/cm3).

The range of a 68 MeV Ne beam in this is 67um.

Range of 16 MeV alphas is 266.5 um.