Attatched are the overlayed compton edges for the calibrated experimental and the GEANT4 simulations. Note p1 and p2 denotes the lower and higher energy compton edges for Yttrium. 

The experimental and simulated histograms are shifted in quite a few of these plots suggesting the calibration was not fully successful. The compton edge for AmBe was difficult to locate and may have contributed to the poor calibration. 

Calibration parameters for each STED detector: With function f=p0+p1*x+p2*x*x

A quadratic function was fitted to the reference point channel (from experimental histogram) and reference point energy (from simulation histogram). The reference point 'r' was r=mean+(FWHM/2) for a gaussian fitted to each compton edge. A quadratic function was used as it fitted the higher energy AmBe reference point better than a linear function. This is highlighted by the comparisson of "STED 2 Calibration" and "STED 2 Example Linear Fit Calibration" plots below. The p0 error is quite large and p2 error very large (larger than the parameter value in STED1) - however the parameters are highly correlated which may have inflated the error. 

CmC histograms were not used as the compton edge could not be located. 

For reference the STED 1 correlation matrix:

All plots in the ratios all look pretty contstant. Zn1 for all detectors seems to have some strange spike in the integral, and a dip in the SILI measurements (and therefore in the SILI/PKUP ratio). 

Det1 & Det4 dont look great for the Integral/Proton plots, im planning to make these plots with the PKUP protons and SILI and then comapre all of those errors and ratios that come from those, so we'll see what that comparison brings. 

Nothing has been seperated by dedicated or paracitic beam yet, so those comparisons need to be made too. 

The EAR2 ratios of BCT/PKUP, BCT/SILI and PKUP/SILI plotted for each run for samples Si, Sinat, Au20, Au22 and Dummy. 

Also included is the normalised counts (counts/BCT) with 7 detectors on one plot (STED8 was ommited).  'counts' for Si was integreated over the Si resonance, for Au it was integrated over the largest resonance. For Dummy and Sinat the counts were integrated over a large range of 1e+4 to 1e+6ns. The Sinat resonance was too small for adequate statistics to only integrate over the resonance hence why a large range was used. The C6D6 normalised counts were not plotted as there seems to be issues with this detector in EAR2. 

There seems to be issues with the EAR2 C6D6 T histograms. For Au the earlier run seems to be shifted for detector 2 compared to the rest. 

For Si plotted is 3 different runs 216123, 216128 and 216135 for both detectors. The histogram is messy but highlights that there is a problem. The single Si resonace should be around 20 000ns and this is only the case for run216128. 

Apologies for no legend on plots. 

Au22
det1 run216158 black
det1 run216109 red
det2 run216158 green
det2 run216109 blue

Au22
det1 run216157 black
det1 run216108 red
det2 run216157 green
det2 run216108 blue
 

The EAR1 ratios of BCT/PKUP, BCT/SILI and PKUP/SILI plotted for each run for samples Si, Sinat goodfellow, Au20, Au22, Empty and Dummy. 

The ratios for BCT/PKUP for Si, Au20, Au22, Dummy, Empty and Sinat goodfellow have been plotted. Also included is the normalised counts (counts/BCT) with all 4 detectors on one plot. Apologies there is not a legend, however det1 is red, det2 is green, det3 black and det4 blue. 'counts' for Si was integreated over the Si resonance, for Au it was integrated over the largest resonance. For Dummy, Empty and Sinat the counts were integrated over a large range of 1e+5 to 1e+7ns. The Sinat resonance was too small for adequate statistics to only integrate over the resonance hence why a large range was used. 

Goodfellow Si-nat mounted at EAR1. First run: 116551

Goodfellow sample has been deposited on a single Mylar foil and glue is drying.

mass = 2.932 g

diameter = 20.0 mm

thickness = 3.98 mm

30Si
Mass: 0.9925(1) g;    Diameter: 22.22(1) mm;    Thickness: 1.77(4) mm;

natSi
Mass: 1.0653(2)g;    Diameter: 19.94(2) mm;    Thickness: 1.91(3) mm;

Mass of sample pre-treatment (sintering ...)

natSi 1.0238 g
30Si:  0.75034 g

EAR1: Si-nat sample fell off the holder during maintenance (before run 116544), appears intact and undamaged. Placed it back in-beam for further EAR1 measurements and subsequent transfer to EAR2.

EAR2: Replaced DUMMY with 30Si. Photo during alignment and photo of sample in holder attached.

8 sTED + 2 C6D6

C6D6: distance = 14 cm, angle = 135 degrees

sTED horizontal ring, distance for each detector from target = 4.5 cm. sTED labeled 8 in the DAQ is actually sTED #9 at n_TOF (actual sTED #8 showed no signal)

sTED1 809V, sTED2 793V, sTED3 813V, sTED4 779V, sTED5 785V, sTED6 800V, sTED7 791V, sTED8 837V

C6D61 (labeled C6D6_M in HV log) 854V, C6D62 (labeled C6D6_N in HV log) 871V

Default TTOFSort dead time setting of 30 ns is ok.

Calibration parameters for each detector:

A linear function was fitted to the reference point channel (from experimental histogram) and reference point energy (from simulation histogram). The reference point 'r' was r=mean+(FWHM/2) for a gaussian fitted to each compton edge. 

The comparrisons between the calibrated experimental and simulation histograms has been attached. P1 (left) and P2 (right) on the Y88 hisograms indicate whether the histograms were scaled with respect to the leftmost or rightmost compton edge (only to allow easier comparrison). 

Broadening parameters applied to the simulations

float a1 = 0.004947965;
float b1 = 0.005227974;
float a2 = 0.007163802;
float b2 = 0.007549987;
float a3 = 0.001256462;
float b3 = 0.006410511;
float a4 = 0.003907402;
float b4 = 0.004033837;

sigma= sqrt(axE+bxE^2) 

Both Au samples (20mm and 22mm) are single mylar.

Both Si30 (22mm) and natSi (20mm) are double mylar.

Empty is single mylar ONLY

Dummy is double mylar + glue 

New 22mm sample compared to old 20mm sample used at the beginning of the campaign + picture of dummy target in the setup.

Si Set up images and documentation.

Detector 1 - C6D6D: Distance= 9 cm, Angle= 135 deg relative to BL (check set up pdf for drawing if unsure), Voltage= 1550 V

Detector 2 - C6D6E: Distance= 9 cm, Angle= 135 deg relative to BL, Voltage= 1590 V

Detector 3 - C6D6H: Distance= 9 cm, Angle= 135 deg relative to BL, Voltage= 1450 V

Detector 4 - C6D6L: Distance= 9 cm, Angle= 135 deg relative to BL, Voltage= 1460 V

Note: Voltages were increased by 30V after the first few runs, these voltages are titled as "new voltages" in the DAQ when they were being tried out, and are now the final voltages.

Photos of the  68Zn(n,gamma) measuremement setup at n_TOF EAR-1.

Attached are the pictures of enriched Si-30 metal pieces.