some photos in high resolution of the test setup 5-10 October 2015

 E = 0.03uA
dE = 0.04uA
PHDI = 0.09uA

- Monitor PHDI - increasing slowly...

Missing/broken items identified

- long rails for fixing chamber on support

- vacuum valve (ours is broken)

- at least 2 lemo - BNC converters

- short M3 screws (photo)

Setup 5.10.22

dE 20 um (ID 2837-33) and 494 um double sided (ID 1194-9)

46 channels (2 connectors missing)

LiF4 in beam 

dE: Big flat cables from preamp 22 and 23 into 1A and 1B

E: from preamp 24+25 go into 2A, 2B and 3A 3B

LEMO converter box: Cable 1: dE

                                   Cable 3: E n+n

                                  unlabeled cable: E p+n

E detector voltage: -133 V, leakage current -0.53 micro-Amp

dE detector voltage -22 V, leakage current -0.03 micro-Amp

For the E detector one of the edge p+n strip bond-wires is suspected broken.

• Start 9th August, access to EAR-2 11 am earliest but can start in rack area before
• Setup to be used: 1 dE (16 strips, 20 um thickness) + 1 E (16x16 strips, 150 um thickness. We have a spare for each thickness
• Sample and detectors to be mounted on the same flange

Things to check:

• alignment with beam centre (lasers and/or gafchromics foils)
• is the setup stable to knockes, can all detector / sample positions be well reproduced when making changes

Once setup us completed:

• checks with pulser
• mounf LiF sample number 3 and run with neutron beam
• check that all strips have signals
• confirm shape of gamma flash and that short times can be anaysed in both detectors (~1.8 us after flash)

If everything working:

• measure LiF-3 and the switch to Al-26
• towards end of the run we can also measure B-3 and the empty brass frame (Frame without mylar)
• proton statistics: 1E17 LiF-3, 1F17 B-3, ~3E17 Empty, 5.5 E18 Al-26

Travel times

Nick: 8-16, Annie 8-12, Tom, 7 -?, Claudia, 8-10, Emmanuel asap until end of run

Measurement runs until Octover 2nd. Disassembly by Nick and Emmanuel.

additional trips during the measurement as required (if something breaks/fails etc. )

Attached: photos of previous setup

TO Do: MCA availability at nTOF for quick noise checks (Nick)

            how many  channels in 14 bit, how many 12 bit (Nick)

          depletion voltages   for detectors (Tom)

          Register the eqipment at CERN as Edinburgh property (Claudia)

Comparison strip 6 amplitude spectra anew (red) vs (old) processing (Screenshot). Slight shift in amplitude and slightly less counts with new processing in t+alpha peaks (1% level). This could be either due to less noise background, shift in neutron energy calibration (amplitude spectra shown with a cut of 100 keV). pdf plot shows new vs old for neutron energy vs counts. only minor differences at low neutron energy, new processing makes spectra cleaner at higher energy.

Shape of the Li 240 keV resonance is shifted in new processing - either due to different offset in tof-ene calibration, or time stamp for signals in one of the processing versions is wrong. Need a new comparison to simulated spectra. 

dE Detector: W1-20 3186-9 20 um

E Detector: W1-150 3458-4 144 um

Voltages and Leakage Currents:

dE: 6 V, 0.02 muA

E: 50 V, 0.05 muA

Gafchromics foil was mounted on empty brass frame back to back with Li sample

Neutron beam goes well through the sample. Centered ~1 cm from sample center. Conclusion: no changes needed (too risky to make it worse and it is ok now)

The rootfiles countsB.root and countsLi.root contain histograms of count spectra that would be expected at n_TOF for a 10B and a 6Li target, respectively. The units in y are arbitrary. This can be used to check, if we can reproduce the expected trend with our Li and B measurements. So the histograms called "counts" can be directly compared to the histograms called "energy" in Sili_deed.c (they should have the same binning). You need to scale the histogram to get a decent overlap. You can use this also to estimate the neutron energy calibration - the thermal bump at low energy will give you a good idea of the flight path length. Structure at high energy will give you a better idea on the offset.

The files 6Li_endf.root and 10B_endf.root are the original cross section files, and countrate_calc.C is the file used to produce the count spectra.

B looks as we are used to , Li tritons are now stopped in the detector and should appear around 2.8 MeV. 

Photos setup

Excel Sheet 

Excel sheet for presence at CERN during 41Ca run. Please update if required. 

https://docs.google.com/spreadsheets/d/19OzH7bpnHb-YeOskNBGlrhEkPZmDsPDw9y0tleU0Soo/edit?gid=0#gid=0

Phtotos of the front & back of the Al target and what it looked like once mounted and in the chamber.

Processed scans of both sides of the Li target showing the beam spot, and an image showing what it looks like to the eye.