PT/35(b) TIMELINE PART V: Scientific Inquiries in 1992

Section 30.0 of the police report deals with PT/35(b) up to the point of its
identification as similar to the Togo timer, on 22 July 1990. Section 30.1 of the police
report states that, following submission of section 30.0 to the Crown, it was requested
that certain further tests which had earlier been carried out on the fragment also be
performed on the control sample piece of MST-13 circuit board, DP/347(a).
[DP/347(a) was one of the various control sample circuit boards obtained during
enquiries at MEBO; it was Crown label 412 at trial.]

The police report records that these 5 tests were carried out in the period from 28 February 1992 to 6 March 1992, and a summary of these tests is contained in the police report. The conclusion of the report states that while none of the scientists would say conclusively that PT/35(b) and DP/347(a) were specifically the same material or from the same source, equally none were of the opinion that the two samples were radically different.

The police officers involved in instructing the tests were DS Peter McAdam (S1371X)
and DC Rolf Buwert (S4649Q). Neither McAdam nor Buwert gave evidence at trial.
McAdam does not have a chapter 10 CP. Buwert does have a ch10 CP but in relation
to these scientific enquiries it is very bald in its terms. Both men have DPs, but they
basically just reflect their HOLMES statements, which record that, starting on 28 Feb
92, at the request of a fiscal depute, they arranged the series of scientific tests on
DP/347(a). Details of these tests follow below.

It is apparent from Crown precognitions that the Crown wanted to have the handwritten statements relating to the scientific examinations that had been carried out in 1990, but for some reason these could not be located and only the HOLMES prints were available. However, the handwritten statements of the witnesses spoken to in 1992 were produced and the Crown lodged these as productions 358 to 365 at trial.

MST13_BOARD

28 February 1992 (Wilkinson – see also 2 March 1990)

According to their HOLMES statements, McAdam and Buwert went to the Wolfson
Centre and met Dr Rosemary Wilkinson by prior arrangement, and she attempted to
examine the whole of DP/347(a) in her scanning electron microscope but due to
technical difficulties this proved impossible, and she was authorised to remove a
sample from the circuit board at a place previously agreed with the fiscal depute. The
corner section was then removed (DP/494, Crown label 411) and put in the scanning
electron microscope.

At the conclusion of the tests Dr Wilkinson produced DP/495 (production 354), a computer disk containing plots of x-ray spectra and data sheet,and she also provided a roll of film containing photographic evidence of her findings, which were detailed in her statement S5579A.

The police report records that Dr Wilkinson was of the opinion that the surface of
DP/347(a) was different from the surface of PT/35(b). She qualified this opinion by
saying that lead, which had a low boiling point, had been lost selectively if PT/35(b)
had suffered flash burning as a result of blast.

Dr Wilkinson’s manuscript statement (prod 364) records that the surface of the new
sample looked different from the fragment.

The fragment’s surface had contained bright “crystallites” 1/2 to 2 microns in diameter, but no such structure was present on DP/494, which contained bright and dark areas 5 to 15 microns in diameter which after analysis were associated with a lead rich metal for the bright areas and a tin rich metal for the dark areas.

No copper was found except at the edge exposed by the cutting of the sample. Dr Wilkinson suggested that this was because in DP/494 had a greater thickness of tin/lead metal covering the copper. She stated that, since the original fragment had been recovered from the scene of an explosion, it was possible that the coating material had been lost in the course of the explosion and that lead, which has a low boiling point, had been lost selectively but she said that this hypothesis should be tested by experiment.

In her CP Dr Wilkinson stated that, on examining the results (DP/495) of her testing
of the piece cut from DP/347(a), in the main areas of the sample tested, no significant
copper could be seen on any spectrum, although copper was noted at the edge cut
kom the sample, where it had been exposed. She stated that this indicated that there
was a consistent, thick layer of tin and lead across the copper base, which you would
expect when the board left the manufacturer. She stated that this supported the theory
she had about PT/35(b) that it had suffered a “loss” of tin and lead, thus exposing the
copper structure below. She was referred to DP/20, photos 1 and 2, which she
identified as photographs of the copper track area of PT/35(b). She had previously
described how these photos depicted patterns of crystals that demonstrated the
presence of copper oxide. She stated that DP/511 (which are not mentioned in her
police statement but which are, according to the police label she signed, photos and a
data sheet taken by her on 28 February 92) are images taken by the scanning electron
microscope. She stated that these images were of the pad area of DP/347(a), whereas
DP/20 was of the copper track area of PT/35(b), and she stated that “Accordingly, the
comments which I have made in my second Police statement in relation to “crystallites” are not appropriate.”

She stated that she would be happy to testify about the tests she carried out and the results, but that she did not believe she was qualified to comment on the reasons why PT/35(b) was in the condition it was in, as any such comments would be entirely speculative.

In her DP Dr Wilkinson referred to the return visit by police in 1992 and said that she
had been asked by them whether the control sample they had brought was the same as
the original sample she had examined, and that all she could say to them was that it
confirmed her original analysis “that the first sample was not a virgin sample”. She
said that one thing it did indicate was that the levels of solder were smooth and level
on the control sample, which was not the case with the original sample. In a note
relating to her comments, it is recorded by the defence to be of interest that she
thought the original fragment did not appear to be explosion damaged and that she did
not count for much given that she is not an expert in the field. She was reprecognosced
by the defence and re-stated that she saw differences between the fragment and the control sample, the latter very clearly showing itself to be a 2 phase alloy of bright and dark bits, being lead and tin, whereas this was not obvious from the fragment.

When asked to clarify why she said the first sample was different from
the second, she said “The first sample was not pristine. It was dirty in the electrical
sense. I spent a long time looking at the second sample – I had the photographs of the
first sample – but not the sample itself. The first sample was difficult it had bits on it
– it had been used – The copper in the second sample was less obvious – which
probably suggests the copper was thinner or the solder layer was thinner [sic – this
should possibly have read thicker].”

Dr Wilkinson did not give evidence. The defence considered calling Dr Wilkinson
because of her comments that she could not see any particles that might be indicative
of explosion damage, but in a filenote it is recorded that the defence felt it potentially
dangerous to call her, given her self-professed lack of expertise.

Comparison between control sample and fragment: on the fragment Dr Wilkinson
could find no trace of lead on the copper track she tested, only copper and tin, it
appears that the sample from DP/347(a) that she tested, DP/494, only contained an
area from the land and did not contain any sample from the copper tracks, hence her
comment in her CP that it had not been appropriate for her to say in her 1992 police
statement that the control sample did not have the crystallites – she had not tested the
corresponding area. She did find quite uniform tin and lead on the land of the control
sample but no copper, which was different from the fragment, where she found traces
of all three in differing proportions. She accepted herself that this could be accounted
for by the fragment losing some tin and lead, perhaps by partial melting, to expose the
copper below.

NB Wilkinson’s signature is visible on the label for DP/347(a).

2 March 1992 (Linsdel/Rawlings/Walker – see also 9 March 1990)

According to their HOLMES statements, by prior arrangement McAdam and Buwert
attended Morton International, Dynachem Division, Warrington and spoke to Robert
Linsdell, who was asked to cause Steven Rawlings to submit DP/347(a) to similar
tests as had been carried out to PT/35(b). Linsdell examined DP/347(a) and DP/494
and asked that a further piece be cut from DP/347(a) so that the piece, DP/498, a resin
encased section, could be produced for photographic examination by microscope (the
HOLMES statements are not clear, but presumably what was meant was that Linsdell
asked for DP/498 to be cut from DP/347(a), after which it was encased in resin to
allow microscope photography). The statements record that 2 photographs (DP/499)
were produced by Philip Michael Walker from this and that the rest of the fragment
cut from DP/347(a), which the statements record was labelled DP/504, was retained.
[See below for discussion re DP/504, as the statements are not totally clear – it does
seem that Walker removed a cross-section from DP/347(a) and then only mounted
part of this, DP/498, the remainder later being designated DP/504. However, the
Crown appeared to proceed on the basis that it was John French of Ciba Geigy that
removed DP/504 from DP/347(a).] It is stated that Steven Rawlings took scrapings
from both sides of DP/347(a) and produced potassium bromide – “KBr Disks” (the
scraping from the non-track side was designated DP/496 (Crown label 408), the
scraping from the track side was DP/497 (Crown label 409)) – to facilitate infrared
spectrometry, and 2 spectra print-outs were obtained and compared to the spectra
print out for PT/35(b) (both spectra print-outs being designated DP/500, production
348) and statements were obtained from the three witnesses.

According to the police report Linsdell and Rawlings’ opinion was that the copper
tracks from DP/347(a) were 35 microns in height, which was similar to the height of
the copper tracks on the fragment. Rawlings concluded from the spectography of
material from both sides of DP/347(a) that all the absorbance peaks in the
“fingerprint” region of the spectrum of PT/35(b) could be matched to the major
absorbance peaks in the spectra for DP/347(a), so that they could be from the same
source, there being no evidence for them not being from the same source.

Linsdell’s manuscript statement (prod 361) bears out the above summary. In addition,
it records his description of DP/347(a) as being a single sided PCB, manufactured
from double-sided laminate material, screen printed with solder mask on the non-track
side, so that the solder mask was for aesthetic reasons and not to act as solder mask.
He states that surface mount technology board was somewhat more advanced in
design that what he envisaged when he saw PT/35(b), it was designed in an unusual
way, but by using surface mount technology the manufacturer reduced the size of the
timer considerably. Surface mount technology had been around for 10 years and in
production for 5 or 6 years. In 1985/6 the technology was not very common, perhaps
5-10% of production, whereas in 1992 it was 50%. The technology had the advantage
of small size, bulk and weight. Linsdell stated that having seen DP/347(a) he now
understood the peculiarities in comparison to the origin sample, as he had suspected
that PT/35(b) was somewhat unusual when he first examined it, and this had been
borne out.

In his CP Linsdell could not at first recall any visit by police officers subsequent to
the first visit in 1990. He was shown DP/347(a) and vaguely recalled having seen it
previously. He confirmed his signature was on the label, but could not recall when or
whether any tests were carried out on this sample. He was shown DP/496 and
DP/497, the scrapings taken from DP/347(a), but had no recollection of them. His
signature was not on the labels for them, although he saw Steven Rawlings’ signature
on the labels. He presumed Rawlings had done the scrapings but did not remember
this. He was shown DP/500, the spectrum printout, but his signature was not on this
label and he had no recollection of having seen it before. He examined the printouts
and said he did not think it possible to say that DP/347(a) and PT/35(b) were the
same. He was prepared to say that there was nothing in the printouts to suggest they
were not the same, but this was as high as he could take it. He was shown DP/498,
the resin encased section from DP/347(a) and vaguely recalled that it was removed by
his colleague Philip Walker. He thought it would have been examined
microscopically but he could not recall this being done. A PF’s note states that
Linsdell was confident but that his role was overstated in the police statements and he
was more a supervisory role, Rawlings having done the work.

In his DP Linsdell did recall the visit of police in 1992 and recalled being shown a
complete circuit board similar to the fragment he had previously been shown. He
knew comparative analytical tests were done on solder mask samples taken from the
complete board, using the same procedures as had been done for the fragment. He
said that from his own observations, he noted certain similarities. He referred to the
two samples having the same curve and routing and similar circuit design, which was
a “design feature”. This uniformity strengthened his belief that both boards had been
produced using the same means of production in a purpose made facility. He thought
it would be “a coincidence of some magnitude” if individual designers were to
produce the same characteristics in isolation, so he was of the belief that the fragment
could very much have been part of a board very similar to the one shown on the
second visit.

Linsdell did not give evidence.

Rawlings’ manuscript statement (prod 360) reflects the summary above, in particular
that in comparing the absorbance peaks for the samples from DP/347(a) and PT/35(b)
in the spectra printout (DP/500), it indicated that the two could have been from the
same source and there was no evidence for them not being- from the same source.

In his CP Rawlings confirmed that on 2/3/92 the police visited again and that he took
the scrapings (DP/496 and 497) from both sides of DP/347(a) and produced spectra.
He stated that only one side, the non-track side, had solder mask on it. He concluded
that the solder masks could be of the same type. There were slight differences in
some of the ratios but these were not significant, there was nothing to suggest they
were not from the same production run. The differences could have been because the
tests were done at different times and also because the original fragment was charred
and very small, thus restricting the sample size it was possible to obtain. He did state
that in court he would not be able to state absolutely that the solder mask on PT/35(b)
was no acrylete based, it being theoretically possible that, in the event the fragment
was exposed to high temperatures, the acrylete could have decomposed leaving the
other materials that would suggest epoxy based coating, as acryletes burn off at much
lower temperature than other parts of solder mask. He stated that this was only a
theory and he had not conducted any tests on it.

In his DP Rawlings recalled the 1992 visit and referred to his notes of it. He did not
add anythmg of note to what is stated above, other than that he took scrapings from
both sides of the board even although it was only solder masked on one side, as it
allowed him a control sample to show the presence of solder mask against.

Rawlings gave evidence but not in relation to the 1992 enquiries.

Walker’s manuscript statement (prod 362) states that he was asked by Linsdell to
prepare a micro section from DP/347(a), which he cut at a point indicated by DS
McAdam. He said he mounted a piece of this cross section into a mounting
compound, which was subsequently polished so that it could be viewed through a
microscope. This was DP/498. Microscopic examination revealed the copper track
“height” to be approximately 35 microns, which is one once weight, very commonly
used in the PCB industry. He produced 2 photographs (DP/499).

The terms of Walker’s police statement would suggest that he cut a cross section from
DP/347(a) and then mounted a piece of this cross-section, i.e. not the whole part that
he removed, into the compound. This would suggest that part of the cross-section that
was cut by Walker was not mounted. This would be consistent with the terms of
McAdam and Buwert’s HOLMES statements, that the mounted part was labelled
DP/498 and the remainder of the cross-section cut from DP/347(a) was labelled
DP/504. However, the statements and precognitions of Linsdell, Rawlings and
Walker do not mention DP/504. It is first mentioned in French’s HOLMES statement
(see 4 March 1992, below) which records that he was told by police that DP/504 had
previously been removed from DP/347(a). This would seem consistent with DP/504
having been removed by Walker. However, the CP of French suggests that the Crown
believed it was he who had removed DP/504, and then had removed DP/505 from
DP/504 (see below). The statements are not completely clear, but they do tend to
suggest that it was Walker and not French who cut DP/504 from DP/347(a). Buwert’s
CP does not mention DP/504 at all.

In his CP Walker stated that he had no recollection of the police attending in 1992
with DP/347(a), and had no recollection of removing a cross section fkom this board.
He confirmed that the label for DP/347(a) bore his signature, as did the label for
DP/498. He stated that the sample had been mounted in compound then polished so it
could be viewed through an optical microscope, and he confirmed that this is the type
of work he would have canied out. He confirmed that the label for DP/499 bore his
signature and that they were attempting to demonstrate the “height” of the copper
tracks on the cross section of the board. He stated that he came to the conclusion that
the height of the sample was approximately 35 microns, which is 1 ounce weight, and
that this was very common in the PCB industry. He said he could not provide the
Scottish investigators with any more information.

In his DP Walker stated that he understood the police revisited on 2 March 1992 but
he could not himself remember the date and that he may have spoken to the officers
on this occasion but to the best of his memory he did not conduct any further tests or
examination on the fragment or any other piece of material.

Walker did not give evidence.

Comparison between control sample and fragment: the height of the copper tracks in
both samples was the same, and the make-up of the solder mask did not appear
different. Linsdell himself made comments about how he felt the two came from a
common source.

NB The signatures of Walker, Linsdell and Rawlings are visible on the label for
DP/347(a).

4 March 1992 (French – see also 8 February 1990 above)

According to their HOLMES statements, on this date McAdam and Buwert travelled
to Ciba Geigy and interviewed John French, who removed from DP/347(a) a small
sample, DP/505 (Crown label 407) to allow infrared spectrometry, and a spectrum,
DP/506 (prod 346) was produced. Mr French then examined DP/12, a sample
removed from PT/35(b), and subjected it to the same test as had been done for
DP/505, and produced another spectrum, again labelled DP/506 (prod 346). French’s
conclusions were included in his statement.

According to the police report the result of French’s analysis was that both samples
from PT/35(b) and from DP/347(a) showed bisphenol A epoxy resin cured with
dicyandiamide, both samples being made from chemically similar materials.

The manuscript statement of French was prod 358. Its terms generally conform to the
summary above. The wording of the statement is not clear, but it seems that DP/505
was not removed direct from DP/347(a), but from DP/504. The terms of the
statement suggest that French was told DP/504 was a section that had previously
already been removed from DP/347(a).

In his CP French at first did not recollect the return visit of officers in 1992. He was
shown DP/347(a) and vaguely recollected it, and he saw his signature of its label. He
recalled noting that certain elements of the board were visually similar to the
fragment. He did not recall analysing the sample. He was then shown DP/504, from
which it seems he removed DP/505, but he did not recall it and did not see his
signature on the label. He was then shown DP/505 and saw his signature on that label, stating that the sample was in a typical Ciba tube. He said it was gradually
coming back to him, and he accepted that he removed this piece, and said he would
have done this to carry out the same tests with a view to comparing the results. He
was shown the spectrum DP/506 and confirmed he had signed that label and had also
signed and dated the spectra, which he accepted was his work. He stated that on
comparing the results, he was prepared to say that the sample was constructed using
the same type of resin as the sample taken from PT/35(b). The same curing agent had
been used, and both samples had been made using chemically similar materials. He
said it was not possible to state that they had been made by the same manufacturer.

A note at the end of the CP states that the police officers would have to speak to
removal of DP/504 from the circuit board as the witness did not recollect this. The
terms of the police statements indicate that he did not remove DP/504, although he
removed DP/505 from DP/504. The implication from the HOLMES statements of
McAdam, Buwert and Philip Walker is that it was Walker at Morton International
(see 2 March 1992, above) that removed DP/504.

French’s DP does not mention the 1992 enquiries (he might have been precognosced
by the defence before the Crown). He did not give evidence.

Comparison between control sample and fragment: it seems to be confirmed that the
resins used to make both samples could have been the same (despite comments made
by French in 1990 that comparison between PT/35(b) and control samples would be
difficult if PT/35(b) had been subjected to extreme heat, which could have changed its
molecular structure).

NB French’s signature is visible on the label for DP/347(a).

5 March 1992

(Worroll / Johnson – see also 11 April 1990 and 23 May 1990 above)

According to their police statements, on this date both officers travelled to Ferranti
International, Oldham, where they interviewed Allan Worroll and caused him to
microscopically examine DP/498, the resin encased sample from DP/347(a), and
asked him to provide a technical description of this item, which he did and is
incorporated into his statement. Worroll also provided a phase diagram, DP/507
(prod 353) to illustrate the differences in structures of tin/lead alloys subjected to heat.

According to the police report Worroll provided a technical description along the lines
of that which he provided for PT/35(b), and he explained that the anomalies apparent
between the two descriptions could be because PT/35(b) was visibly altered by its
close proximity to an explosion. The phase diagram he provided showed the sharp
melting point of electronic grade solder.

Worroll’s manuscript statement (prod 363) records that he examined DP/347(a) and
DP/498 and also DP/501, DP/502 and DP/503, which were enlargements of
photographs of the original fragment (photos 336, 334 and 333 of the RARDE report
respectively) and he gave a further technical description. It appears that this
description corresponds to the 7 points in the description of PT/35(b) listed in DP/141,
which is not a production but which the Commission obtained from D&G. In his
description of DP/347(a) Worroll said:

(1) DP/347(a) is single-sided, there being no evidence of through-hole plate connections [just as he described PT/35(b) DP/141];

(2) the sample is 1 ounce copper clad FR4 laminate – a layer of glass cloth [this
appears consistent with what he said about PT/35(b) in DP/141, although there is more detail in the PT/35(b) description];

(3) the sample has solder mask applied to the non component side and it appears to have been screen printed on. It is approximately 0.0007 inches thick. Worroll could not understand why the “back-side” of the PCB had solder mask [presumably this is for aesthetic reasons, as described by Linsdell in his statement prod 3611 [in his description of PT/35(b) in DP/141 Worroll said solder mask had been applied to both sides of the board, it being a wet epoxy based type either screen printed or brushed onto the board. He could see no reason for the backside of the board to be solder masked. In his 1992 statement Worroll suggested that the reason for the differences in his description of PT/35(b) and DP/347(a) could be that PT/35(b) had been visibly altered by its close proximity to an explosion – although this is not likely to explain why PT/35(b) had solder mask on both sides – this appears to be the only difference between the descriptions of the two samples
here; and Worroll said in his CP that the fragment had mask on one side only];

(4) the tracks are nominally 0.010 inches wide with spacings nominally 0.018 inches between the tracks [this is consistent with his description of PT/35(b) in DP/141];

(5) Worroll said the solderable deposit on DP/347(a) was much thicker than on PT/35(b) [this does not directly correspond to any description of thickness of solder deposit of
PT/35(b), although at point 5 of DP/141 it is recorded that Worroll said the tracks
were coated with pure tin, probably from an electroless tin solution, presumably to aid
solderability];

(6) Worroll said he could not comment on this as no assembly on this
sample had been effected [in DP/141 he stated that normal electronic grade solder had
been used to make the solder connection – presumably because nothing had been
soldered to the connection on DP/347(a) there was no solder present, hence the reason
he could not comment];

(7) he stated that DP/347(a) was a commercially manufactured board [in DP/141 he was recorded as saying the copper pad and tracks suggested PT/35(b) could be home-made, but the machined radius of the board suggested commercial machining operation].

Worroll’s manuscript statement then refers to illustrating the differences in structures
of tin/lead alloys when viewed by scanning electron microscope by him drawing
DP/507, the phase diagram of the tin/lead alloy system. The statement explains that
electronic grade solder has fine grain structure whereas compositions lying well
outside the range e.g. plumbers solder do not have the sharp melting point of
electronic grade solder but melt or cool over a range of temperature and deposit areas
of tin or lead rich alloy dependent on the original composition.

In his CP Worroll was shown DP/347(a) and stated that he did not particularly recall
it, although he could see it was a single sided board that bore many similarities to the
fragment PT/35(b). He said it was not possible to comment on the solder mask on the
board. He noted that the manufacturer used surface mount technology which would
have been fairly high-tech in 1985. He would not have expected the board to have
been manufactured domestically as the quality of the tracking was fairly high. He
thought domestic manufacture would be unable to produce anything that complex due
to the degree of tracking and the close proximity of components. He noted that he
signed the label for DP/347(a) but could not recall carrying out any tests on it. He had
no reason to doubt the police officers if they indicated that he did carry out tests on it.
He was shown DP/498 and likewise had no recollection of examining the sample.

In his DP Worroll did not mention the visit in 1992.

In evidence Worroll was able to recall being visited by police on an occasion when
they brought with them an entire circuit board. There was some questioning from the
advocate depute about exactly what the police asked him to do and there was some
confusion on the part of the witness as to what he was being asked, but he maintained
that he had only been asked to examine the circuit board visually and had not
conducted any tests on it. He was not examined further about the results of his visual
identification or the comparison to PT/35(b).

Comparison between control sample and fragment: Generally Worroll seemed content
that the particular aspects of the control sample were the same as the fragment. He
was recorded as stating that the control sample was only solder masked on the
backside, whereas the fragment was solder masked on both sides, but his position on
both these matters appears to have altered over time (he said at precognition that the
fragment was solder masked on one side only and said he could not comment on the
solder mask on the control sample) and his opinion on whether there was solder mask
on both sides of the fragment was disputed by other experts (above). Worroll also
said the solderable deposits were thicker on the control sample than on the fragment.
This would be consistent with what Wilkinson observed, so the explanations
Wilkinson offered for this, about possible loss of tin and lead because of heating, may
apply. This might be what prompted Worroll’s explanations of the melting point of
electronic solder, as evidenced by his phase diagram (DP/507).

The HOLMES statements of the officers record that, later the same day, the two
officers attended Dr David Johnson’s laboratory at the Centre for Surface and
Material Analysis in Manchester. Dr Johnson examined DP/504 (label 406, the
fragment removed by those at Morton International, see 2 March 92, above) using
Secondary Ion Mass Spectrometry. A brief statement was obtained from Dr Johnson,
who promised to provide a full analysis report including comparisons between the
analyses of DP/504 and PT/35(b) later.

The police report states that following brief comparison between the data held on
PT/35(b) and that which Dr Johnson obtained from DP/347(a) there was nothing to
suggest that the two samples were not the same, and reference is made to his analysis
report which by the time of the police report had been received (DP/510).

Johnson’s manuscript statement (prod 365) basically reflects what is said above. He
also explained that the brief comparison indicated nothing to suggest the two samples
were not the same, confirmation that the two samples were the same was not possible
because of the qualitative techniques used in the testing. Johnson also stated that on
the track side of the new sample the results showed several differences in quality of
metals, particularly lead, present. However, the physical characteristics of the sample
were quite different in terms of the surface conductivity and the fact that the first
sample had suffered heat damage more to the track side that the reverse. Intense heat
could have altered the surface of the track face of the sample.

In his CP Johnson could not recall the visit by police officers in 1992. He was shown
his analysis report, DP/510, and recognised it as his work. He stated that the report
detailed that he was approached again in March 92 by the same police officers [in fact
it was different officers] who asked him to examine another sample. This report
includes the spectra data produced from his previous report on PT/35(b). Johnson
was shown DP/347(a) at precognition but had no recollection of examining the board.
He saw his name on the label and presumed it was the board he used as a control
sample for his second report. He said his report suggested he carried out analytical
procedures on a fragment of the sample board which had been removed previously.
He was shown DP/504 and said this was definitely not mounted by him. He said he
had signed the label and this was the fragment he had used in the additional test. He
washed DP/504 in Heptane, as he had done for PT/35(b). He stressed that his results
were qualitative and were restricted to comparing peaks produced in the spectra. He
stated that the intensities of the peaks were different, which meant the same elements
were present on the surface of the fragments but in different quantities. In summary,
he said PT/35(b) and DP/347(a) were more similar than the other control samples he
used in his first report on PT/35(b) (Sefolam and Dytron). At its highest, he was
prepared to say that there were no substances present which suggested that the two
were not the same, when one looks at the qualities of the substances rather than the
quantities. He stated that he did not bother to compare the composition of the solder
on the tracking side of DP/347(a) and PT/35(b) because the potential for heat damage
could affect the composition of the solder.

In his DP Johnson said that the police asked him to conduct an analysis of the solder
content from the upper side of the board which he agreed to do, but he recalled
explaining to the police that he would consider this invalid as a comparison with
PT/35(b), as PT/35(b) had been shown to be damaged and significantly altered in
constitution. He said he stated this in his report. He stated that he conducted analysis
of the underside of DP/347(a) in the same manner as had been done for PT/35(b) and
showed that the surface chemistry of the two samples were similar, but that this did
not mean that the samples were identical or that they had come from the same
manufacturer.

Johnson did not give evidence. His report, DP/510, was production 355.

Comparison between control sample and fragment: Dr Johnson did not find anything
to indicate that they were not the same, and he was clear in what he said that the heat
exposure suffered by PT/35(b) would alter the constitution of the solder etc., so that,
although there was a difference between the upper side of the two samples, in that the
lead content of DP/347(a) was much more intense than on PT/35(b), this could be
explained by the evident heat damage suffered in particular to that side of the
fragment.

NB Worroll and Johnson’s signatures are visible on the label for DP/347(a).

6 March 1992 (Whitehead – See also 15 Feb 1990 above)

On this date both officers travelled to Circuit Foil UK (formerly Yates Circuit Foils)
at Silloth, and interviewed Michael Whitehead, who examined the matt side
topography of the copper tracks on DP/504 (label 406) by using a scanning electron
microscope and produced 2 micrographs, A and B, designated DP/508 (prod 347).
Whitehead’s conclusions were said to be noted in the statement obtained from him.

According to the police report Whitehead concluded from the micrograph photos of
PT/35(b) and DP/504 that both copper samples had been made by Gould Electronics,
although he was also of the opinion that the copper foil for DP/504 was manufactured
some time earlier than the copper foil for PT/35(b).

Whitehead’s manuscript statement (prod 359) gives further details of the testing he
conducted, and explains that micrograph A shows in general the result of the
preparation, and micrograph B shows the matt side topography of one of the peeled
tracks at magnification of just in excess of 1000 times. The statement records that the
relationship of the dendrites to the base foil pyramids was representative of a product
manufactured by Gould, but that the previous micrographs (DP/14) of DP/10, the
sample from PT/35(b), suggested that DP/504 was manufactured earlier because the
number of peaks per unit area was less that depicted for DP/10. He suggested that the
time difference could have been as little as a few months, and there was still no doubt
that the micrographs of DP/10 and DP/504 were similar to the extent that the foil was
manufactured by the same process.

In his CP Whitehead confirmed he had signed the label for DP/504 and for DP/347(a)
but he had no recollection of this examination. He was shown DP/508  (prod 347), the
two micrographs of DP/504 and compared these to DP/14 (prod 340), the photographs
of DP/10, and said that the samples were from the same source or they used the same
technology, and that the timescale was almost the same, any slight difference in
timescale would be insignificant. He could not remember providing a statement to
police officers, and only had a very hazy recollection of the second examination
which came back to him during precognition. He stated that although he could not
remember the details, what he would have told the police at the time would have been
accurate. He was then reprecognosced on 5 June 2000 and again examined prod 347,
the micrographs of DP/504. He stated that the features most closely resembled those
of the fragment PT/35(b) as opposed to Yates or Gould control samples. He
suggested that they could have come from the same roll of copper foil, but thought
this to be unlikely. He was asked whether heat would change the appearance of the
foil, and explained that although heat would affect the foil internally,
there would be a no identifiable changes in appearance under scanning electron microscope unless the foil was exposed to temperatures over 800 degrees, which would melt the copper.

None of the samples showed signs of melting.

In his DP Whitehead did recall the 1992 investigation. His DP was taken after his CP.
He thought Williamson might have been one of the officers who saw him in 1992 but
could not be sure. He recalled the police had another piece of circuit board with them,
around 25mm each side, it looked like a portion of a circuit board (presumably
DP/504). It was in much better condition than the previous piece (i.e. PT/35(b)). He
conducted the same testing on it as he had done previously, except that on this
occasion he cut a complete piece off the sample, including the laminates, whereas
previously he had just peeled off a small bit of the copper foil. The micrograph he
obtained indicated to him that, as with the previous sample, the copper was not from
Circuit Foil and not from Gould and, as with the other one, had the style of having
been manufactured in the Far East. He was not as confident that this one was from
the Far East, as by 1992 it was not as easy as it had been in 1990 to distinguish
between countries of manufacture, as they were becoming more similar in
appearance. He stated that both the samples from 1990 and 1992 were the product of
the same manufacturing technology of copper foil, but were not identical.

Whitehead gave evidence, but basically only about the removal of DP/10 from
PT/35(b). He testified that he was able to identify that the company he worked for
had not manufactured the product but could not be definitive about an alternative
source.

Comparison between control sample and fragment: as mentioned under 15 February
1990 above, Whitehead appears originally to have been of the view that the copper on
PT/35(b) and on DP/347(a) was manufactured by Gould, but by the time of
precognition he was of the view that it was not Gould but possibly of unknown Far
Eastern manufacture. Most important is that he thought the two samples were similar
and had come from the same technology, and although he said in his DP that they
were not identical, his CP only indicates that they perhaps did not come from the
same roll of copper, and he stated that they were more similar to each other than to
Yates or Gould samples. He did make the comment that the copper would only
change appearance if exposed to temperatures over 800 degrees. It is clear from
comments of other experts (above) that the ftagment had visibly suffered heat
damage.

NB Whitehead’s signature is not obvious on the label for DP/347(a).

Whitehead was the last expert to examine DP/347(a) in 1992.

Consideration

Overall, there are some unsatisfactory aspects to the accounts of some of the scientific
witnesses e.g. a number of them could not recall the second visit by police in 1992;
Wilkinson realised she had made an error in her police statement re the comment
about crystallites; Johnson realised he made an error re heptane; Whitehead was
inconsistent re whether the copper came from Gould or the Far East; Worroll’s view
on the solder masking varied over time; and there are certain inconsistencies between
some of the opinions. However, having examined all the accounts and productions in
relation to these enquiries, the evidential chain appears sound an there is nothing
which leads the Commission to doubt that the same fragment was examined in each
case. The 1992 enquires appear consistent with the fragment having come from a
circuit board of similar manufacture to the control sample obtained from MEBO.

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